19-4410; Rev 5; 9/11 19-4410; Rev 5; 9/11 评 估 板 可 提 供 评估板 可提供 概述 概述 M A X8903A - M A X8903E / M A X8903G/ M A X8903H / MAX8903J/MAX8903N/MAX8903Y是集成的单节Li+电池 MAX8903A/MAX8903E/MAX8903G/MAX8903H/MAX8 充电器和Smart Power SelectorTM (智能电源选择器)，提 903J/MAX8903N/MAX8903Y是集成的单节Li+电池充 供双电源输入(交流适配器和USB)。开关模式充电器工作 电器和Smart Power SelectorTM(智能电源选择器)，提 在较高的开关频率，可以省去散热器并允许使用小尺寸 供双电源输入(交流适配器和USB)。开关模式充电器工 外部元件。该器件可采用独立的USB电源或交流适配器供 作在较高的开关频率，可以省去散热器并允许使用小 电，也可以用一个输入端接收两路电源输入。芯片集成了 尺寸外部元件。该器件可采用独立的USB电源或交流 所有充电功能和用于切换电池、外部电源、负载的功率开 适配器供电，也可以用一个输入端接收两路电源输入。芯片 关。无需外部MOSFET、反向保护二极管和检流电阻。 集成了所有充电功能和用于切换电池、外部电源、负 MAX8903_优化工作于智能化电源管理模式，可充分利用 载的功率开关。无需外部MOSFET、反向保护二极管 有限的USB或适配器电源的供电能力。电池充电电流和 和检流电阻。 SYS输出限流均可独立设置。在保证系统供电的前提下 为电池充电。充电电流和SYS输出限流可设置在最高2A， MAX8903_优化工作于智能化电源管理模式，可充 USB输入限流可设置在100mA或500mA。输入选择电路 分利用有限的USB或适配器电源的供电能力。电池 能够自动地将系统供电电源从电池切换至外部电源。器件 充电电流和SYS输出限流均可独立设置。在保证系 工作在4.15V至16V直流输入电压范围，输入端具有高达 统供电的前提下为电池充电。充电电流和SYS输出 20V的保护；USB输入范围为4.1V至6.3V，输入端具有最 限流可设置在最高2A，USB输入限流可设置在 高8V保护。 100mA或500mA。输人选择电路能够自动地将系 未接输入电源时，MAX8903_内部电路可以阻止电流从电 统供电电源从电池切换至外部电源。器件工作在 池、系统倒灌到直流电源、USB输入。其它功能包括：预 4.15V至16V直流输入电压范围，输入端具有高达 充检测及定时器、快充定时器、过压保护、充电状态指 20V的保护；USB输入范围为4.1V至6.3V，输入端 示和故障指示输出、电源就绪监视器以及电池热敏电阻 具有最高8V保护。 检测等。此外，片内热管理电路可以根据需要降低电池 未接输入电源时，MAX8903_内部电路可以阻止电 充电速率或交流适配器的充电电流，以防止充电器过热。 流从电池、系统倒灌到直流电源、USB输入。其它 MAX8903_采用4mm x 4mm、28引脚薄型QFN封装。 功能包括：预充检测及定时器、快充定时器、过压 不同版本的MAX8903_提高了设计灵活性，便于选择不 保护、充电状态指示和故障指示输出、电源就绪监 同的系统电源电压、电池预检验门限和电池满充电压。 视器以及电池热敏电阻检测等。此外，片内热管理 MAX8903B/MAX8903E/MAX8903G的电池检测功能还包 电路可以根据需要降低电池充电速率或交流适配器 选型指南 部分。 含供电使能控制，详细信息请参考 的充电电流，以防止充电器过热。MAX8903_采用 4mm x 4mm、28引脚薄型QFN封装。 应用 不同版本的MAX8903_提高了设计灵活性，便于选 PDA、掌上电脑和 便携式多媒体播放器 择不同的系统电源电压、电池预检验门限和电池满 无线手持装置 充电压。MAX8903B/MAX8903E/MAX8903G的电 移动互联网设备 池检测功能还包含供电使能控制，详细信息请参考 个人导航设备 超便携移动PC 选型指南 部分。 智能蜂窝电话 S 高效DC-DC转换器，无需散热器 S Efficient 4MHz开关频率，允许使用小尺寸外部元件 ' DC-DC Converter Eliminates Heat ' Switching for Tiny External Components S 4MHz 立即开启—能够在无电池/低电池电压下工作 ' On—Works with No/Low Battery S Instant 两路限流输入—交流适配器或USB ' Dual Current-Limiting Inputs—AC Adapter or USB 适配器/USB/电池供电自动切换，支持瞬变负载 Automatic Adapter/USB/Battery Switchover to 50mΩ系统至电池开关导通电阻 Support Load Transients 支持USB规范 50m System-to-Battery Switch Supports USB Spec S 热敏电阻检测 ' Thermistor Monitor S 集成检流电阻 ' Integrated Current-Sense Resistor S 无需外部MOSFET或二极管 ' No External MOSFETs or Diodes S 4.1V至16V输入工作电压范围 定购信息 Ordering Information TEMP RANGE PIN-PACKAGE MAX8903AETI+T PART -40°C to +85°C 28 Thin QFN-EP* MAX8903BETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903CETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903DETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903EETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903GETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903HETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903JETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903NETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903YETI+T -40°C to +85°C 28 Thin QFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. + '表示无铅(Pb)/符合RoHS标准的封装。 4.1V to 16V Input Operating Voltage Range **EP EP = = Exposed 裸焊盘。pad. T = 卷带包装。 Typical Operating 典型工作电路 AC AC LX LX ADAPTER ADAPTER OR USBOR USB DC DC 应用 PDA、掌上电脑和 无线手持装置 个人导航设备 智能蜂窝电话 SYSSYS CURRENT PWM STEP-DOWN PWM 移动互联网设备 超便携移动PC USB LOAD LOAD CURRENT CURRENT CHARGE CHARGE AND SYSAND LOAD SYS LOAD SWITCH SYSTEM SYSTEM LOAD LOAD SWITCH STEP-DOWN USB Selector Guide appears at end of data sheet. Smart Power Selector是Maxim Integrated Products, Inc.的商标。 Smart Power Selector is a trademark of Maxim Integrated Products, Inc. CSCS CHARGE CHARGE CURRENT 便携式多媒体播放器 选型指南在数据资料的最后给出。 特性 Features BAT USB BAT USB MAX8903_ MAX8903_ BATTERY BATTERY GND GND 引脚配置在数据资料的最后给出。 ����������������������������������������������������������������� Maxim Integrated Products 1 1 ________________________________________________________________ Maxim Integrated Products 本文是英文数据资料的译文，文中可能存在翻译上的不准确或错误。如需进一步确认，请在您的设计中参考英文资料。 本文是英文数据资料的译文，文中可能存在翻译上的不准确或错误。如需进一步确认，请在您的设计中参考英文资料。 有关价格、供货及订购信息，请联络Maxim亚洲销售中心：10800 852 1249 (北中国区)，10800 152 1249 (南中国区)， 有关价格、供货及订购信息，请联络Maxim亚洲销售中心：10800 852 1249 (北中国区)，10800 152 1249 (南中国区)，或访 或访问Maxim的中文网站：china.maxim-ic.com。 问Maxim的中文网站：china.maxim-ic.com。 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 ABSOLUTE MAXIMUM RATINGS DC, LX to GND .......................................................-0.3V to +20V DC, LX GND .......................................................-0.3V 0.3V) DCM to to GND .............................................-0.3V to (VDCto+ +20V + 0.3V) DCM GND ..............................................-0.3V to (VDC to DC to to SYS .................................................................-6V +20V DC to BST toSYS GND.................................................................-6V ...........................................................-0.3V to to +20V +26V to GND ...........................................................-0.3V toto+26V BST TO LX................................................................-0.3V +6V BST TO LX ................................................................-0.3V USB to GND .............................................................-0.3V to to +6V +9V GND .............................................................-0.3V to USB to SYS..................................................................-6V to +9V +9V USB SYS..................................................................-6V VL to to GND ................................................................-0.3V to to +9V +6V VL to GND ................................................................-0.3V +6V THM, IDC, ISET, CT to GND........................-0.3V to (VVL +to0.3V) THM, IDC, to GND........................-0.3V to (VVL + 0.3V) DOK, FLT, ISET, CEN, CT UOK, CHG, USUS, CEN, UOK, USUS, DOK, BAT,FLT, SYS, IUSB, CS CHG, to GND ................................-0.3V to +6V BAT, SYS,..............................................................-0.3V IUSB, CS to GND ................................-0.3V to SYS to BAT to +6V +6V SYSEP to BAT ...............................................................-0.3V +6V PG, (exposed pad) to GND .............................-0.3V toto+0.3V PG,Continuous EP (exposed pad) to(total GNDin.............................-0.3V to +0.3V DC Current two pins).....................2.4A RMS DC Continuous (total in two pins)......................2.4ARMS USB ContinuousCurrent Current......................................................1.6A LX Continuous Current (total in two pins)......................2.4ARMS USBContinuous ContinuousCurrent Current.......................................................1.6A CS (total in two pins) ......................2.4ARMS LX Continuous SYS ContinuousCurrent Current(total (totalinintwo twopins).......................2.4A pins) .......................3ARMS RMS CS Continuous BAT ContinuousCurrent Current(total (totalinintwo twopins) pins)......................2.4A .......................3ARMS RMS SYSShort Continuous Current (total in two pins) .......................3ARMS VL Circuit to GND .............................................Continuous BAT Continuous Current (total in .......................3ARMS +70NC) Continuous Power Dissipation (Ttwo A = pins) Short Circuit to GND .............................................Continuous VL28-Pin Thin QFN-EP = +70°C) Dissipation (TAabove Continuous MultilayerPower (derate 28.6mW/°C +70NC) ..........2286mW 28-Pin Thin QFN-EP QFN-EP Multilayer (derate 28.6mW/°C above +70°C) ..........2286mW Single-Layer (derate 20.8mW/°C above +70NC)...1666.7mW 28-Pin Thin QFN-EP Range ...........................-40NC to +85NC Operating Temperature Single-Layer (derate 20.8mW/°C above +70°C)...1666.7mW Junction Temperature Range ............................-40NC to +150NC Operating Temperature Range ...........................-40°Ctoto+150NC +85°C Storage Temperature Range .............................-65NC Junction Temperature Range ............................-40°C to +150°C Lead Temperature (soldering, 10s) ................................+300NC Storage Temperature Range .............................-65°C to +150°C Soldering Temperature (reflow) ......................................+260NC Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional Stresses beyond thoseat listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress only, and functional operation of the device these or any other conditions beyond those indicated in the operational sections of the specifications is notratings implied. Exposure to absolute ratingatconditions for extended periods beyond may affect device reliability. operationmaximum of the device these or any other conditions those indicated in the operational sections of the specifications is not implied. Exposure to ELECTRICAL CHARACTERISTICS ELECTRICAL (V =V = 5V, VCHARACTERISTICS = 4V, circuit of Figure 2, T DC USB BAT A = -40NC to +85NC, unless otherwise noted. Typical values are at TA = +25NC.) (VDC =1)VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note PARAMETER CONDITIONS MIN TYP MAX UNITS 16 V DC INPUT DC Operating Range 4.15 No valid USB input Valid USB input 3.9 4.0 4.0 4.3 4.1 4.4 V 16.5 17 17.5 V Charger enabled, no switching, VSYS = 5V 2.3 4 Charger enabled, f = 3MHz, VDC = 5V 15 Charger enabled, VCEN = 0V, 100mA USB mode (Note 2) 1 2 Charger enabled, VCEN = 5V, 100mA USB mode (Note 2) VDCM = 0V, VUSUS = 5V 1 0.10 2 0.25 DC Undervoltage Threshold When VDOK goes low, VDC rising, 500mV typical hysteresis DC Overvoltage Threshold When VDOK goes high, VDC rising, 500mV typical hysteresis DC Supply Current mA DC High-Side Resistance 0.15 Ω DC Low-Side Resistance 0.15 Ω 0.31 Ω DC-to-BAT Dropout Resistance Assumes a 40mΩ inductor resistance (RL) DC-to-BAT Dropout Voltage When SYS regulation and charging stops, VDC falling, 200mV hysteresis 0 Minimum Off Time (tOFFMIN) MAX8903A/B/C/D/E/H/J/Y MAX8903G 70 4 ns VDC = 8V, VBAT = 4V VDC = 5V, VBAT = 3V 3 VDC = 9V, VBAT = 4V 1 VDC = 9V, VBAT = 3V 1 2 0.5 VDC = 6V, VSYS = 4V mV ns DC Step-Down Output CurrentLimit Step Range DC Step-Down Output Current Limit (ISDLIM) 30 100 Minimum On Time (tONMIN) Switching Frequency (fSW) 15 MHz 2 RIDC = 3kΩ 1900 2000 2100 RIDC = 6kΩ RIDC = 12kΩ 950 450 1000 500 1050 550 _______________________________________________________________________________________ A mA 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 DC USB BAT A A = +25NC.) (VDC = (Note 1)VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER DC Soft-Start Time DC Output Current 500mA USB Mode (Note 3) DC Output Current 100mA USB Mode (Note 2) SYS to DC Reverse Current Blocking CONDITIONS MIN TYP MAX UNITS No valid USB input 1 ms Valid USB input before soft-start 20 µs VDCM = 0V, VIUSB = 5V 450 475 500 mA VDCM = 0V, VIUSB = 0V 90 95 100 mA VSYS = 5.5V, VDC = 0V 0.01 µA USB INPUT USB Operating Range 4.1 6.3 USB Standoff Voltage V 8 V USB Undervoltage Threshold When VUOK goes low, VUSB rising, 500mV hysteresis 3.95 4.0 4.05 V USB Overvoltage Threshold When VUOK goes high, VUSB rising, 500mV hysteresis 6.8 6.9 7.0 V USB Current Limit VIUSB = 0V (100mA setting) 90 95 100 VIUSB = 5V (500mA setting) 450 475 500 1.3 3 ISYS = IBAT = 0mA, VCEN = 0V USB Supply Current ISYS = IBAT = 0mA, VCEN = 5V VUSUS = 5V (USB suspend mode) Minimum USB to BAT Headroom 0 USB to SYS Dropout Resistance USB Soft-Start Time 0.8 2 0.115 0.25 15 30 0.2 0.35 mA mA mV Ω VUSB rising 1 ms VDC falling below DC UVLO to initiate USB soft-start 20 µs SYS OUTPUT Minimum SYS Regulation Voltage (VSYSMIN) ISYS = 1A, VBAT < VSYSMIN Regulation Voltage ISYS = 0A MAX8903A/B/E/G/Y 3.0 MAX8903C/D/H/J/N 3.4 MAX8903A/C/D/H/N/Y MAX8903B/E/G MAX8903J V 4.3 4.4 4.5 4.265 4.325 4.395 4.4 4.5 4.55 MAX8903A/C/D/H 40 MAX8903B/E/G/J/N/Y 25 V Load Regulation ISYS = 0 to 2A mV/A CS to SYS Resistance VDC = 6V, VDCM = 5V, VSYS = 4V, ICS = 1A 0.07 Ω SYS to CS Leakage VSYS = 5.5V, VDC = VCS = 0V 0.01 µA BAT to SYS Resistance VDC = VUSB = 0V, VBAT = 4.2V, ISYS = 1A 0.05 0.1 Ω BAT to SYS Reverse Regulation Voltage VUSB = 5V, VDC = 0V, VIUSB = 0V, ISYS = 200mA 50 75 100 mV SYS Undervoltage Threshold SYS falling, 200mV hysteresis (Note 4) 1.8 1.9 2.0 V _______________________________________________________________________________________ 33 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (V =V = 5V, V = 4V, circuit of Figure 2, T = -40NC to +85NC, unless otherwise noted. Typical values are at T MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (V =V = 5V, V = 4V, circuit of Figure 2, T = -40NC to +85NC, unless otherwise noted. Typical values are at T DC USB BAT A A = +25NC.) (VDC = VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX 4.179 4.200 4.221 UNITS BATTERY CHARGER MAX8903A/B/C/G/H BAT Regulation Voltage (VBATREG) MAX8903D/E IBAT = 0mA MAX8903J TA = -40°C to +85°C 4.158 4.200 4.242 TA = +25°C 4.079 4.100 4.121 TA = -40°C to +85°C 4.059 4.100 4.141 TA = +25°C 4.328 4.350 4.372 TA = -40°C to +85°C 4.307 4.350 4.394 TA = +25°C 4.129 4.150 4.171 TA = -40°C to +85°C 4.109 4.150 4.192 -150 -100 -60 MAX8903A/C/D/H/J/N/Y 2.9 3.0 3.1 MAX8903B/E/G 2.4 2.5 2.6 RISET = 600Ω 1800 2000 2200 RISET = 1.2kΩ (MAX8903A/C/D) 900 1000 1100 RISET = 2.4kΩ 450 500 550 MAX8903Y/N Charger Restart Threshold TA = +25°C Change in VBAT from DONE to fast-charge BAT Prequal Threshold (VBATPQ) VBAT rising 180mV hystersis Prequal Charge Current Percentage of fast-charge current set at ISET Fast-Charge Current DONE Threshold (ITERM) 10 Percentage of fast-charge, IBAT decreasing RISET Resistor Range mV V % 10 0.6 V mA % 2.4 kΩ ISET Output Voltage 1.5 V ISET Current Monitor Gain 1.25 mA/A BAT Leakage Current No DC or USB input With valid input power, VCEN = 5V 0.05 4 3 6 µA Charger Soft-Start Time 1.0 ms Charger Thermal Limit Temperature 100 °C Charge current = 0 at +120°C 5 %/°C Prequalification Time CCT = 0.15µF 33 min Fast-Charge Time CCT = 0.15µF 660 min MAX8903A/C/D/H/J/N/Y (fixed) 15 s Charger Thermal Limit Gain CHARGER TIMER Top-Off Timer (tTOP-OFF) MAX8903B/E/G, CCT = 0.15µF Timer Accuracy 132 -15 min +15 % Timer Extend Current Threshold Percentage of fast-charge current below which the timer clock operates at half-speed 40 50 60 % Timer Suspend Current Threshold Percentage of fast-charge current below which timer clock pauses 16 20 24 % 4 4 _______________________________________________________________________________________ 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 DC USB BAT A A = +25NC.) (VDC = (Note 1)VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS MIN TYP MAX UNITS THERMISTOR MONITOR THM Threshold, Hot When charging is suspended, 1% hysteresis 0.27 x VVL 0.28 x VVL 0.29 x VVL V THM Threshold, Cold When charging is suspended, 1% hysteresis 0.73 x VVL 0.74 x VVL 0.75 x VVL V THM Threshold, Disabled THM function is disabled below this voltage 0.0254 x VVL 0.03 x VVL 0.036 x VVL V THM Threshold DC, USB Enable MAX8903B/MAX8903E/MAX8903G 0.83 x VVL 0.87 x VVL 0.91 x VVL V -0.100 ±0.001 +0.200 MAX8903A/C/D/H/J/N/Y THM Input Leakage MAX8903B/E/G THM = GND or VL; TA = +25°C THM = GND or VL; TA = +85°C THM = GND or VL; TA = -40°C to +85°C µA ±0.010 -0.200 ±0.001 +0.200 THERMAL SHUTDOWN, VL, AND LOGIC I/O: CHG, FLT, DOK, UOK, DCM, CEN, USUS, IUSB Logic-Input Thresholds (DCM, CEN, USUS, IUSB) Logic-Input Leakage Current (CEN, USUS, IUSB) High level 1.3 Low level 0.4 Hysteresis VINPUT = 0V to 5.5V (MAX8903A/C/D/H/J/N/Y) VINPUT = 0V to 5.5V (MAX8903B/E/G) 50 TA = +25°C -1.000 TA = +85°C TA = -40°C to +85°C ±0.001 µA ±0.001 +0.200 TA = +25°C 0.001 1 TA = +85°C 0.01 Logic-Input Leakage Current (DCM) VDCM = 0V to 16V VDC = 16V Logic Output Voltage, Low (CHG, FLT, DOK, UOK) Sinking 1mA 8 Sinking 10mA 80 Open-Drain Output Leakage VOUT = 5.5V Current, High (CHG, FLT, DOK, UOK) mV +1.000 ±0.010 -0.200 TA = +25°C 0.001 TA = +85°C 0.01 V 50 1 µA mV µA _______________________________________________________________________________________ 5 5 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (V =V = 5V, V = 4V, circuit of Figure 2, T = -40NC to +85NC, unless otherwise noted. Typical values are at T Low level (DCM, CEN, USUS, IUSB) 0.4 50 Hysteresis TA = +25°C VINPUT = 0V to 5.5V (MAX8903A/C/D/H/J/N/Y) Logic-Input Leakage Current (CEN, USUS, IUSB) Logic-Input Leakage Current -1.000 TA = +85°C TA = -40°C to +85°C VDCM = 0V to 16V TA = +25°C -0.200 +0.200 0.001 1 µA 0.01 A 8 50 mV 80 TA = +25°C 0.001 1 µA VOUT = 5.5V ELECTRICAL CHARACTERISTICS (continued) Current, High (CHG, FLT, DOK, UOK) 0.01 TA = +85°C ELECTRICAL CHARACTERISTICS (continued) (V =V = 5V, V = 4V, circuit of Figure 2, T = -40NC to +85NC, unless otherwise noted. Typical values are at T DC USB BAT A A = +25NC.) (VDC = VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS VL Output Voltage VDC = VUSB = 6V VL UVLO Threshold MIN TYP MAX IVL = 0 to 1mA (MAX8903A/C/D/H/J/N/Y) 4.6 5.0 5.4 IVL = 0 to 10mA (MAX8903B/E/G) 4.6 5.0 5.4 UNITS V 3.2 V Thermal Shutdown Temperature 160 °C Thermal Shutdown Hysteresis 15 °C VVL falling; 200mV hysteresis Limits 100% production production tested tested at at TTA == +25°C. +25°C.Limits Limitsover overthe theoperating operatingtemperature temperaturerange rangeare areguaranteed guaranteedby bydesign. design. Limits are are 100% A For the 100mA USB mode using the DC input, the step-down regulator is turned off and its high-side switch operates as a For the 100mA USB mode using the DC input, the step-down regulator is turned off and its high-side switch operates as a linear regulator with a 100mA current limit. The linear regulator’s output is connected to LX and its output current flows with ainto 100mA current limit. The linear regulator’s output is connected to LX and its output current flows linear regulator through the inductor CS and finally to SYS. through the inductor into CSthe and finallycurrent to SYS. Note 3: For the 500mA USB mode, actual drawn from USB is less than the output current due to the input/output current of the DC-DC Note 3: ratio For the 500mA USBconverter. mode, the actual current drawn from USB is less than the output current due to the input/output current Note 4: For protection, SYS sources 25mA below VSYS = 400mV, and 50mA for VSYS between 400mV and 2V. ratioshort-circuit of the DC-DC converter. Note 4: For short-circuit protection, SYS sources 25mA below VSYS = 400mV, and 50mA for VSYS between 400mV and 2V. Note 1: 1: Note Note 2: Note 2: MAX8903A/B/C/D/E/H/J/N/Y BATTERY CHARGER EFFICIENCY vs. BATTERY VOLTAGE EFFICIENCY (%) VDC = 8V 60 50 VDC = 12V 40 30 70 VDC = 9V 60 50 VDC = 12V 40 30 IBAT = 0.15A 20 IBAT = 1.5A IBATT = 0.15A 20 10 IBATT = 1.5A 1.0 1.5 2.0 2.5 3.0 3.5 4.0 BATTERY VOLTAGE (V) 4.5 5.0 4.0 3.5 VBAT = 3V 3.0 2.5 VBAT = 4V 2.0 1.5 1.0 RISET = 1.2kΩ VCEN = 0V 0.5 10 0 66 VDC = 6V 80 4.5 MAX8903A toc02 VDC = 5V 70 90 SWITCHING FREQUENCY (MHz) 80 100 MAX8903A toc01a 90 MAX8903A/B/C/D/E/H/J/N/Y SWITCHING FREQUENCY vs. VDC MAX8903G BATTERY CHARGER EFFICIENCY vs. BATTERY VOLTAGE MAX8903A toc01 100 典型工作特性 Typical Operating (TA = +25°C, unless otherwise noted.) EFFICIENCY (%) MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y µA ±0.001 = 16V V (DCM) T = +85°C 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 Sinking 1mA Logic Output Voltage, Low 用于USB和适配器供电系统 (CHG, FLT, DOK, UOK) USB和适配器供电系统 Sinking 10mA Open-Drain Output Leakage +1.000 ±0.010 VINPUT = 0V to 5.5V (MAX8903B/E/G) DC mV ±0.001 0.0 0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 BATTERY VOLTAGE (V) 4.5 5.0 4 6 8 10 12 DC VOLTAGE (V) _______________________________________________________________________________________ 14 16 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 MAX8903A/B/C/D/E/H/J/N/Y MAX8 9 0 3 A/ B/ C/ D/ E / H/ J / N/ Y SYS SYSEFFICIENCY EFFI CI ENCY v s SYS . S YS OUTCURRENT PUT CURRE NT vs. OUTPUT VBAT = 4V VBAT = 3V 0.4 MAX8903A toc03 60 VDC = 11V 50 VDC = 16V 40 30 RISET = 1.2kI VCEN = 0V 0 6 8 10 12 14 10 30 VDC = 6V 1000 0 10000 10 1 100 1000 10,000 USB SUPPLY CURRENT vs. USB VOLTAGE USB SUPPLY CURRENT vs. USB VOLTAGE (SUSPEND) BATTERY LEAKAGE CURRENT vs. BATTERY VOLTAGE 0.6 CHARGER DISABLED 0.4 140 120 100 80 60 40 0.2 20 0 0 80 2 3 4 5 6 7 70 60 50 40 30 20 10 USB SUSPEND 1 MAX8903A toc06 MAX8903A toc04 0.8 NO DC OR USB INPUT 0 0 1 2 3 4 5 6 0 7 1 2 3 4 5 USB VOLTAGE (V) BATTERY VOLTAGE (V) BATTERY LEAKAGE CURRENT vs. AMBIENT TEMPERATURE CHARGE CURRENT vs. BATTERY VOLTAGE—USB MODE CHARGE CURRENT vs. BATTERY VOLTAGE—DC MODE 400 CHARGE CURRENT (mA) 70 60 50 40 30 20 350 300 VIUSB = VUSB 250 200 VIUSB = 0V 150 100 10 NO DC OR USB INPUT 0 -15 10 35 TEMPERATURE (°C) 60 85 1000 CHARGE CURRENT (mA) 80 CHARGE ENABLED IBAT SET TO 1.5A MAX8903D VBAT RISING 450 1200 MAX8903A toc08 MAX8903A toc07 500 800 6 MAX8903A toc09 USB VOLTAGE (V) 90 -40 VDC = 9V SYS OUTPUT CURRENT (mA) 1.0 0 VDC = 12V 40 SYS OUTPUT CURRENT (mA) CHARGER ENABLED 1.2 100 VDC = 16V 50 DC VOLTAGE (V) 1.6 1.4 10 1 60 10 0 16 70 20 VDC = 4.5V MAX8903A toc05 4 80 VDC = 6V 20 0.2 USB SUPPLY CURRENT (mA) 70 VCEN = 1 90 BATTERY LEAKAGE CURRENT (nA) 0.6 100 SYS EFFICIENCY (%) 1.0 0.8 80 SYS EFFICIENCY (%) 1.2 VCEN = 1V VSYS = 4.4V 90 USB QUIESCENT CURRENT (µA) SWITCHING FREQUENCY (MHz) 1.4 BATTERY LEAKAGE CURRENT (nA) 100 MAX8903A toc02a 1.6 MAX8903G SYS EFFICIENCY vs. SYS OUTPUT CURRENT MAX8903A toc03a MAX8903G SWITCHING FREQUENCY vs. VDC CHARGER ENABLED IBAT SET TO 1A IDC SET TO 2A MAX8903A/C/H VBAT RISING 600 400 200 50 0 1.5 2.0 2.5 3.0 3.5 BATTERY VOLTAGE (V) 4.0 4.5 0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 BATTERY VOLTAGE (V) _______________________________________________________________________________________ 7 7 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y Typical Operating Characteristics (continued) 典型工作特性(续) (TA = +25°C, unless otherwise noted.) 典型工作特性(续) Typical Operating Characteristics (continued) NORMALIZED BATTERY REGULATION VOLTAGE vs. AMBIENT TEMPERATURE 1.005 1.000 0.995 0.990 0.985 -40 -15 10 35 60 100.4 100.3 100.2 100.1 100.0 99.9 3.5 2.5 2.0 99.7 1.0 -40 -15 10 35 60 VUSB RISING 0.5 22ppm/°C 99.5 VUSB FALLING 3.0 RSYS = 1MΩ 0 1 0 85 2 3 4 5 6 7 USB VOLTAGE (V) MAX8903A/C/D/H/N/Y SYS VOLTAGE vs. DC VOLTAGE SYS VOLTAGE vs. SYS OUTPUT CURRENT, DC INPUT SYS VOLTAGE vs. SYS OUTPUT CURRENT, USB INPUT 2.0 VDC FALLING 1.5 VCEN = 5V VBAT = 0V VUSB = 0V 0.5 2 4 6 8 10 12 14 16 4.3 MAX8903A/C/D/H, MAX8903N/Y, VDC = 5.75V VDC = 5.75V 4.2 MAX8903B/E/G, VDC = 5.75V 4.1 0 0.5 1.0 VL WITH NO LOAD AND DCDC OFF (VUSUS = 5V) VL AND DCDC WITH FULL LOAD (VUSUS = 0V) 2 1 VBAT = 3.6V VUSB = 0V 0 4 6 8 0 100 10 12 14 16 18 20 DC VOLTAGE (V) 200 300 400 SYS OUTPUT CURRENT (mA) CHARGE PROFILE—1400mAh BATTERY ADAPTER INPUT—1A CHARGE MAX8903A toc17 6.0 IDC SET TO 1A IBAT SET TO 2A 5.5 5.0 4.5 VBAT (V) 5 2 MAX8903_, VUSB = 0V 3.8 2.0 1.5 MAX8903A toc16 6 0 MAX8903B/E/G, VUSB = 5V 4.1 SYS OUTPUT CURRENT (A) VL VOLTAGE vs. DC VOLTAGE 3 MAX8903A/C/D/H, MAX8903N/Y, VUSB = 5V VUSB = 5V 4.2 3.9 MAX8903_, VDC = 0V 3.8 DC VOLTAGE (V) 4 4.3 4.0 3.9 18 MAX8903J, VUSB = 5V 4.4 4.0 1.0 VDC = 0V, VBATT = 4V 4.5 VBAT 4.0 3.5 3.0 1.2 1.0 0.8 0.6 2.5 2.0 1.5 IBAT 1.0 0.5 0 0.4 0.2 MAX8903A/B/C/G/H 0 20 40 60 80 100 TIME (min) 8 _______________________________________________________________________________________ 8 0.0 120 140 IBAT (A) 2.5 4.6 SYS VOLTAGE (V) VDC RISING 3.0 MAX8903J, VDC = 5.75V 4.4 SYS VOLTAGE (V) 3.5 VUSB = 0V 4.5 MAX8903A toc14 MAX8903A toc13 4.6 MAX8903A toc15 TEMPERATURE (°C) 4.0 VL VOLTAGE (V) 4.0 1.5 99.6 VCEN = 5V VBAT = 0V VDC = 0V 4.5 99.8 85 4.5 0 5.0 TEMPERATURE (°C) 5.0 0 100.5 SYS VOLTAGE (V) 1.010 MAX8903A/C/D/H/N/Y SYS VOLTAGE vs. USB VOLTAGE MAX8903A toc11 VUSB = 5V, VBAT = 4V NORMALIZED BATTERY REGULATION VOLTAGE (%) NORMALIZED CHARGE CURRENT 1.015 MAX8903A toc10 NORMALIZED CHARGE CURRENT vs. AMBIENT TEMPERATURE MAX8903A toc12 (TA = +25°C, unless otherwise noted.) SYS VOLTAGE (V) MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 500 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 MAX8903A/B/C/G/H CHARGE PROFILE—1400mAh BATTERY USB INPUT—500mA CHARGE MAX8903A toc18 5.0 0.45 4.0 0.40 0.25 IBAT 2.0 0.20 1.5 0.15 MAX8903A/MAX8903B/MAX8903C IUSB SET TO 500mA IBAT SET TO 2A 0.5 0 0 IBAT (A) 0.30 2.5 1.0 20mV/div AC-COUPLED VOUT 0.35 VBAT 3.0 MAX8903A toc19 0.50 4.5 3.5 VBAT (V) MAX8903A/B/C/D/E/H/J/N/Y DC SWITCHING WAVEFORMS—LIGHT LOAD 0.10 5V/div VLX 0V ILX 0.05 RSYS = 44Ω 0 20 40 60 80 100 120 140 160 180 200 500mA/div 0A 200ns/div TIME (min) MAX8903A/B/C/D/E/H/J/N/Y DC SWITCHING WAVEFORMS—HEAVY LOAD MAX8903G DC SWITCHING WAVEFORMS—LIGHT LOAD MAX8903A toc20 MAX8903A toc19a 50mV/div AC-COUPLED VSYS VLX VDC = 9V, L = 2.2µH CSYS = 22µF, RSYS = 44I MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 典型工作特性(续) Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) 10V/div 20mV/div AC-COUPLED VOUT 5V/div 0V VLX 0V 1A/div ILX 0A ILX 500mA/div RSYS = 5Ω DC CONNECT WITH USB CONNECTED (RSYS = 25Ω) MAX8903G DC SWITCHING WAVEFORMS—HEAVY LOAD MAX8903A toc21 MAX8903A toc20a VSYS VDC = 9V, L = 2.2µH CSYS = 22µF, RSYS = 5I CEN = 1 50mV/div AC-COUPLED VSYS 0V IUSB 2V/div 347mA 475mA 500mA/div 500mA/div -IBAT = CHARGING IBAT ILX 3.6V IDC 10V/div VLX 0A 200ns/div 1µs/div 0A 500mA/div -335mA 1A/div 0A 1µs/div 200µs/div _______________________________________________________________________________________ 9 9 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 Typical Operating Characteristics (continued) 典型工作特性(续) (TA = +25°C, unless otherwise noted.) DC CONNECT WITH NO USB (RSYS = 25Ω) DC DISCONNECT WITH NO USB (RSYS = 25Ω) MAX8903A toc22 3.84V 3.6V VSYS 3.6V VBAT IBAT 2V/div 3.44V 5V/div CDC CHARGING IDC MAX8903A toc23 CSYS CHARGING 850mA 0A 1A/div 3.68V VSYS 5V/div -IBAT = CHARGING IBAT 144mA BATTERY CHARGER SOFT-START -1A 144mA -1A 1A/div 40µs/div MAX8903B/E SYS LOAD TRANSIENT MAX8903A toc24a MAX8903A toc24b 4.400V MAX8903A VDC = 10.5V L = 2.2µH CSYS = 10µF RIDC = 3kI (2A) DCM = HIGH CEN = 1 20mV/div AC-COUPLED 4.360V 4.325V VSYS 500mA/div 0A 0A ISYS 500mA/div 0A 0A 100µs/div 100µs/div MAX8903G SYS LOAD TRANSIENT USB CONNECT WITH NO DC (RSYS = 25Ω) 4.305V 1A ISYS MAX8903A toc25 VSYS 50mV/div VDC = 9V L = 2.2µH CSYS = 22µF RIDC = 3kI (2A) DCM = 1 CEN = 1 0A 100µs/div 10 20mV/div 1A 4.325V 10 MAX8903B VDC = 10.5V L = 2.2µH CSYS = 22µF RIDC = 3kI (2A) DCM = HIGH CEN = 1 4.305V 1A MAX8903A toc24c VSYS 1A/div -IBAT = CHARGING MAX8903A/C/D/H SYS LOAD TRANSIENT ISYS 1A/div 0A 850mA 400µs/div VSYS 2V/div 3.6V VBAT IDC 3.6V 3.6V 3.75V 3.5V 5V 5V/div VUSB CUSB CHARGING 2V/div 475mA 500mA/div IUSB 500mA/div 0A IBAT 144mA BATTERY CHARGER SOFT-START 500mA/div -330mA 400µs/div ______________________________________________________________________________________ 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 (TA = +25°C, unless otherwise noted.) USB DISCONNECT WITH NO DC (RSYS = 25Ω) USB SUSPEND MAX8903A toc26 3.6V VSYS VUSB 2V/div 5V/div 5V 475mA IUSB 500mA/div VSYS IUSB IBAT VUSUS -330mA 144mA 100µs/div 0V 475mA 3V 5V/div VUSUS 500mA/div 0A IUSB 2V/div 3.7V 500mA/div IBAT -475mA USB RESUME MAX8903A toc27 500mA/div 3V 5V/div CUSB CHARGING 475mA 0A 3.6V VSYS IBAT 0A MAX8903A toc28 0V 3.8V 500mA/div 3.6V 2V/div 0A 200µs/div BATTERY CHARGER SOFT-START -475mA 500mA/div 200µs/div MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y Typical Operating Characteristics (continued) 典型工作特性(续) 引脚说明 Pin Description 引脚 PIN 1, 2 1, 2 3, 4 名称 NAME PG 降压低边同步n沟道MOSFET的功率地，两个PG引脚必须在外部连接在一起。 Power Ground for Step-Down Low-Side Synchronous n-Channel MOSFET. Both PG pins must be PG 直流电源输入。DC能够向SYS提供高达2A的电流。DC支持交流适配器和USB输入，DC限流根据所使用的输入 connected together externally. 电源通过DCM、IUSB或IDC设置，请参考表2。两个DC引脚必须在外部连接在一起。请在DC和PG之间连接一 DC Power Input. DC is capable of delivering up to 2A to SYS. DC supports both AC adapter and USB 个至少4.7μF的陶瓷电容。 inputs. The DC current limit is set through DCM, IUSB, or IDC depending on the input source used. See DC 3, 4 功能 FUNCTION DC Table 2. Both DC pins must be connected together externally. Connect at least a 4.7µF ceramic capacitor 直流电源输入的限流模式设置。置于逻辑高电平时，直流输入电流门限由IDC与GND之间的电阻设置；置于逻 from DC to PG. 辑低电平时，直流输入电流门限在内部设置为500mA或100mA，由IUSB的逻辑输入设置。DCM (阳极)与DC Current-Limit Mode Setting for the DC Power Input. When logic-high, the DC input current limit is set by (阴极)之间接有一个内部二极管，如图1所示。 5 DCM 6 5 DCM 高边MOSFET驱动电源。用一个0.1μF陶瓷电容将BST旁路至LX。 BST 7 IUSB the resistance from IDC to GND. When logic-low, the DC input current limit is internally programmed to 500mA or 100mA, as set by the IUSB logic input. There is an internal diode from DCM (anode) to DC USB限流设置输入。将IUSB驱动至逻辑低电平时，USB电流门限为100mA；将IUSB驱动至逻辑高电平 (cathode) as shown in Figure 1. CT 充电定时器设置输入。CT和GND之间的电容(CCT)用于设置快充和预充故障定时器，该引脚接GND时禁用定时器。 6 8 7 9 8 10 11 9 1210 时，USB电流门限为500mA。 High-Side MOSFET Driver Supply. Bypass BST to LX with a 0.1µF ceramic capacitor. 直流电源就绪输出。当在DC上检测到有效输入时，将低电平有效的开漏输出拉至低电平。当充电器被禁用 DOK USB Current-Limit Set Input. Drive IUSB logic-low to set the USB current limit to 100mA. Drive IUSB logicIUSB (CEN为逻辑高电平)时，DOK仍然保持有效输出。 high to set the USB current limit to 500mA. 逻辑电路LDO输出。VL为LDO输出，该输出向MAX8903_内部电路供电并向BST电容充电。在VL和GND之间连 VL DC Power-OK Output. Active-low open-drain output pulls low when a valid input is detected at DC. DOK DOK 接一个1μF的陶瓷电容。 BST is still valid when the charger is disabled (CEN high). Logic LDO Output. VL is the output of an LDO that powers the MAX8903_ internal circuitry and charges 直流电源限流设置输入。在IDC和GND之间连接一个电阻(R IDC)，当DCM为逻辑高电平时，降压调节器的电流 the BST capacitor. Connect a 1µF ceramic capacitor from VL to GND. 门限设置为0.5A至2A。 Charge Timer Set Input. A capacitor (CCT) from CT to GND sets the fast-charge and prequal fault timers. GNDCT 地，GND是内部电路的低噪声接地端。 IDC VL Connect to GND to disable the timer. 11 IDC DC Current-Limit Set Input. Connect a resistor (RIDC) from IDC to GND to program the current limit of the step-down regulator from 0.5A to 2A when DCM is logic-high. 12 GND Ground. GND is the low-noise ground connection for the internal circuitry. ______________________________________________________________________________________ 11 11 MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器， 用于USB和适配器供电系统 引脚说明(续) 引脚 名称 功能 13 ISET 充电电流设置输入。ISET和GND之间的电阻(RISET)用于设置快充电流，最大值为2A。预充电流为快充电流的10%。 14 CEN 充电器使能输入。CEN接GND时，如果DC或USB连接到有效电源则使能电池充电；接VL时，或将其驱动至逻 辑高电平，则禁止电池充电。 15 USUS USB挂起输入。USUS驱动至逻辑高电平时进入USB挂起模式，USB电流降低至115μA，并在内部将SYS短路 至BAT。 16 THM 热敏电阻输入。将一个负温度系数(NTC)热敏电阻连接在THM和GND之间。将一个阻值等于+25°C时热敏电阻 阻值的电阻连接在THM和VL之间。当热敏电阻超出高温、低温门限时，充电器被挂起。将THM连接至GND 时，禁用热敏电阻温度检测。 17 USB USB电源输入。USB能够向SYS提供100mA或500mA电流，取决于IUSB逻辑输入的设置。在USB和GND之间 连接一个4.7μF的陶瓷电容。 18 FLT 19 UOK 20, 21 BAT 22 CHG 充电器状态输出。当电池处于快充或预充电状态时，低电平有效的开漏输出被拉至低电平；否则，CHG为高阻态。 23, 24 SYS 系统电源输出。当DC或USB无效，或者SYS负载超过输入电流门限时，SYS通过内部50mΩ系统负载开关连接 至BAT。 当DC或USB连接有效电源时，SYS电压限制在VSYSREG。系统负载(ISYS)超过DC或USB电流门限时，SYS被调 节到低于BAT 50mV，输入电源和电池都向SYS供电。 利用X5R或X7R陶瓷电容将SYS旁路至GND，SYS电容(CSYS)的最小推荐值参见表6。两个SYS引脚必须在外部 连接到一起。 25, 26 CS 70mΩ电流检测输入。降压电感连接在LX和CS之间。当降压调节器开启时，CS和SYS之间有一个70mΩ电流 检测MOSFET；当降压调节器关闭时，内部CS MOSFET断开，防止电流从SYS倒灌至DC。 27, 28 LX 电感连接端，将电感连接在LX和CS之间。两个LX引脚必须从外部连接在一起。 — EP 裸焊盘，将裸焊盘连接至GND。裸焊盘连接并不能替代相应引脚的接地要求。 12 故障指示输出。若电池定时器在快充或预充完成之前超时，低电平有效的开漏输出将被拉至低电平。 USB电源就绪输出。当在USB上检测到有效输入时，低电平有效的开漏输出被拉至低电平。充电器禁用(CEN 为逻辑高)时，UOK仍然保持有效。 电池连接端，连接到单节Li+电池。当DC或USB存在有效电源时，电池通过SYS充电。当DC和USB均不存在有效 电源时，或当SYS负载超过输入电流门限时，BAT向SYS供电。两个BAT引脚必须在外部连接到一起。 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 AC ADAPTER DC LX BST CS MAX8903_ DC POWER MANAGEMENT PWR OK SYS Li+ BATTERY CHARGER AND SYS LOAD SWITCH PWM STEP-DOWN REGULATOR DOK MAX8903A-E/G/H/J/N/Y PG CHARGER CURRENTVOLTAGE CONTROL SET INPUT LIMIT TO SYSTEM LOAD ISET BATTERY CONNECTOR BAT BAT+ + BAT- USB USB POWER MANAGEMENT USB PWR OK THERMISTOR MONITOR (SEE FIGURE 7) CURRENTLIMITED VOLTAGE REGULATOR UOK IC THERMAL REGULATION NTC VL CHARGE TERMINATION AND MONITOR SET INPUT LIMIT T THM CHG DC DC MODE USB LIMIT 500mA DCM IUSB 100mA USB SUSPEND USUS FLT CHARGE TIMER INPUT AND CHARGER CURRENT-LIMIT SET LOGIC CT CEN IDC GND DC LIMIT EP 图1. 功能框图 Figure 1. Functional Block Diagram ______________________________________________________________________________________ 13 13 MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 USB和适配器供电系统 用于USB和适配器供电系统 RPU 4 x 100kΩ 1 2 PG PG MAX8903_ CDC 4.7µF DOK 4 DC 6 CBST 0.1µF FLT UOK 3 DC ADAPTER TO VL CHG BST 27 LX ISET 18 19 25 CS (SEE TABLE 5 FOR INDUCTOR SELECTION) 26 CS IDC USB PWR OK 8 DC PWR OK 22 CHARGE INDICATOR 13 RISET 11 RIDC 28 LX L1 1µH FAULT OUTPUT SYS 24 SYS 23 BAT 21 BAT 20 TO SYSTEM LOAD CSYS (SEE TABLE 6 FOR CSYS SELECTION) USB 17 VBUS USB CUSB 4.7µF GND TO DC 5 OFF CHARGE ON 14 500mA 100mA 7 USB SUSPEND 15 10 CCT 0.15µF CBAT 10µF 1-CELL LI+ DCM VL 9 CVL 1µF CEN THM IUSB RT 10kΩ 16 NTC 10kΩ USUS CT GND 12 EP Figure 2. Typical Application Circuit Using a Separate DC and USB Connector 图2．典型应用电路，使用独立的DC和USB连接器 Circuit Description The MAX8903_ is a dual input charger with 电路说明 a 16V input for a wide range of DC sources and USB inputs. The IC MAX8903_为双输入充电器，输入为16V宽范围直流电源和 includes a high-voltage (16V) input DC-DC step-down USB电源。IC内部包括一路高压(16V)输入DC-DC降压转 converter that reduces charger power dissipation while 换器，在保证系统负载供电的同时有效降低充电器功耗。 also supplying power to the system load. The step降压转换器可向系统、电池或两者组合提供高达2A的电流。 down converter supplies up to 2A to the system, the battery, or a combination of both. 14 14 A USB charge input can charge the battery and power the system from a USB power source. When powered USB充电输入可以通过USB电源向电池充电并向系统供电。 from USB or the DC input, system load current peaks 当由USB或DC输入供电时，如果系统负载电流峰值超出了 that exceed what can be supplied by the input are sup输入电源的供电能力，不足部分可由电池补充。 plemented by the battery. MAX8903_还利用一个片上50mΩ MOSFET管理负载与电 The MAX8903_ also manages load switching from the 池和外部电源之间的切换。该开关在输入电源过载时，能 battery to and from an external power source with an 够通过电池支持负载的峰值电流。 on-chip 50m MOSFET. This switch also helps support ______________________________________________________________________________________ 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 1 2 CDC 4.7µF VBUS CBST 0.1µF ID GND FLT UOK 3 DC DOK CHG BST 27 LX ISET 18 499kΩ 25 CS 26 CS IDC (SEE TABLE 5 FOR INDUCTOR VALUE SELECTION) 17 USB ADAPTER 5 OFF CHARGE ON 14 500mA 100mA 7 USB SUSPEND 15 10 CCT 0.15µF USB FAULT OUTPUT 19 USB PWR-OK 8 DC PWR-OK 22 CHARGE INDICATOR 13 RISET 11 RIDC 28 LX L1 1µH DC MODE PG MAX8903_ 6 D+ TO VL PG 4 DC D- MAX8903A-E/G/H/J/N/Y RPU 4 x 100kΩ SYS 24 SYS 23 BAT 21 BAT 20 TO SYSTEM LOAD CSYS (SEE TABLE 6 FOR CSYS SELECTION) CBAT 10µF 1-CELL LI+ DCM VL 9 CVL 1µF CEN THM IUSB RT 10kΩ 16 NTC 10kΩ USUS CT GND 12 EP Figure 3. Typical Application Circuit Using a Mini 5 Style Connector or Other DC/USB Common Connector 图3．典型应用电路，使用Mini 5型连接器或其它DC/USB普通连接器 load peaks using battery power when the input source is overloaded. 如图1所示，该IC包括完备的充电器功能，具有热敏电阻 监测器、故障定时器、充电状态指示和故障指示输出。还 As shown in Figure 1, the IC includes a full-featured charger with thermistor monitor, fault timer, charger 包括USB和DC电源就绪指示，可灵活调节充电电流、输入 status, and fault outputs. Also included are power-OK 电流门限和最小系统电压(按比例降低充电电流，以保持系 signals for both USB and DC. Flexibility is maintained 统电压正常)。 with adjustable charge current, input current limit, and 当管芯温度超过+100°C时，MAX8903_会限制充电电流， a minimum system voltage (when charging is scaled 从而防止高温环境下出现过热。 back to hold the system voltage up). The MAX8903_ prevents overheating during high ambient temperatures by limiting charging current when the DC输入—高速滞回降压调节器 die temperature exceeds +100°C. 如果存在有效的DC输入，则关闭USB电源通路，由高频 降压调节器将DC输入转换成SYS和电池充电的供电电源。 DC Input—Fast Hysteretic ，图4)，电 如果电池电压高于最小系统供电电压(V SYSMIN Step-Down Regulator 池充电器将系统供电电压连接至电池，以获得最低功耗。 If a valid DC input is present, the USB power path is 利用三个反馈信号控制降压调节点：IDC设置的最大降压 turned off and power for SYS and battery charging is supplied by the high-frequency step-down regulator 输出电流、ISET设置的最大充电电流以及最高管芯温度。 from DC. If the battery voltage is above the minimum 反馈信号只需最小的电流控制电感的平均输出电流。这种 system voltage (VSYSMIN, Figure 4), the battery charger 机制使电池充电的总功耗最小，电池能够在保持最小系统 connects the system voltage to the battery for lowest 电压波动的前提下化解负载瞬变的影响。 ______________________________________________________________________________________ 15 15 MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 表1．图2和图3的外部元件列表 Table 1. External Components List for Figures 2 and 3 COMPONENT (FIGURES 2 AND 3) CDC, CUSB FUNCTION PART Input filter capacitor 4.7µF ceramic capacitor CVL VL filter capacitor 1.0µF ceramic capacitor CSYS SYS output bypass capacitor 10µF (MAX8903A/MAX8903C/MAX8903D/MAX8903H/MAX8903J) or 22µF (MAX8903B/MAX8903E/MAX8903G/MAX8903Y) ceramic capacitor CBAT Battery bypass capacitor 10µF ceramic capacitor CCT Charger timing capacitor 0.15µF low TC ceramic capacitor Logic output pullup resistors 100kΩ Negative TC thermistor Philips NTC thermistor, P/N 2322-640-63103, 0kΩ ±5% at +25°C THM pullup resistor 10kΩ RPU (X4) THM RT RIDC DC input current-limit programming resistor 3kΩ ±1%, for 2A limit RISET Fast-charge current programming resistor 1.2kΩ ±1%, for 1A charging L1 DC input step-down inductor 1µH inductor with ISAT > 2A power dissipation. The step-down regulation point is 如果电池电压低于V then controlled bySYSMIN three，充电器不直接将系统供电电压 feedback signals: maximum )略高于VSYSMIN ，如图4所示。 连接至电池，系统电压(V step-down output currentSYS programmed at IDC, maximum 电池充电器独立控制电池的充电电流。根据MAX8903_版 charger current programmed at ISET, and maximum 设置为3.0V或3.4V，参见表6。 本的不同，V die temperature. feedback signal requiring the SYSMINThe smallest current controls the average output current in 电池充电至VSYSMIN电压以上50mV后，系统供电电压被连 the inductor. This scheme minimizes total power dissi接至电池。随后，电池快充电流控制降压转换器建立平均 pation for battery charging and allows the battery to 电感电流，以满足输入限流和快充电流限制的要求。 absorb any load transients with minimum system voltage disturbance. DC-DC降压控制机制 专有的滞回电流PWM控制机制可确保工作在较高的开关 If the battery voltage is below VSYSMIN, the charger does not directly connect the system voltage to the battery 频率，允许使用小尺寸外部元件。反馈控制信号需要最小 and the system voltage (VSYS) is slightly above VSYSMIN 的输入电流，控制电感的峰值和谷值电流的中点。纹波电 as shown in Figure 4. The battery charger independently 流由内部设置，使转换器工作在4MHz频率。当输入电压 controls the battery charging current. VSYSMIN is set to 降至输出电压附近时，工作在非常高的占空比，由于存在 either 3.0V or 3.4V based on the version of MAX8903_. 最小关断时间，达不到4MHz工作频率。控制器提供最小 See Table 6. 关断时间、峰值电流调节。类似地，当输入电压较高时， After the battery charges to 50mV above VSYSMIN, the 由于存在最小导通时间，不能工作在4MHz频率，此时控 system voltage is connected to the battery. The battery 制器采用最小导通时间、谷电流控制。这种情况下，电感 fast-charge current then controls the step-down con的纹波电流始终保持最小，能够在给定电容下有效降低 verter to set the average inductor current so that both SYS的纹波电压。为了避免工作频率波动，纹波电流随输 the programmed input current limit and fast-charge cur入电压、输出电压而变化。然而，频率也会随着工作条件 rent limit are satisfied. 典型工作特性 部分。 的不同而发生变化，请参考 DC-DC Step-Down Control Scheme A proprietary hysteretic current PWM control scheme ensures fast switching and physically tiny external components. The feedback control signal that requires the smallest input current controls the center of the peak and valley currents in the inductor. The ripple current is internally set to provide 4MHz operation. When the input voltage decreases near the output voltage, very high duty cycle occurs and, due to minimum off-time, 16 16 4MHz operation is not achievable. The controller then DC模式(DCM) provides minimum off-time, peak current regulation. 如表2所示，DC输入可接受交流适配器(最高2A)和USB (最 Similarly, when the input voltage is too high to allow 高500mA)电源。DCM逻辑输入置为高电平时，DC输入处 4MHz operation due to the minimum on-time, the con于适配器模式，DC输入电流限制由IDC与GND之间的电阻 troller becomes a minimum on-time, valley current regulator. In this way, ripple current (R IDC)设置。根据下式计算R IDC: in the inductor is always as small as possible to reduce voltage on SYS for RIDC = 6000V/Iripple a given capacitance. The rippleDC-MAX current is made to vary DCM逻辑输入置为低电平时，DC输入电流限制由IUSB逻 with input voltage and output voltage in a way that 辑输入在内部设置为500mA或100mA。IUSB逻辑输入为 reduces frequency variation. However, the frequency 高电平时，DC输入电流限制为500mA，DC输入通过降压 still varies somewhat with operating conditions. See the Typical Operating Characteristics. 调节器为SYS供电。IUSB逻辑输入为低电平时，DC输入 电流限制为100mA。在100mA模式下，降压调节器关闭， DC Mode (DCM) 高边开关将构成线性稳压器，具有100mA的限流。线性稳 As shown in Table 2, the DC input supports both AC 压器的输出连接至LX，输出电流经电感流入CS，最终流 adapters (up to 2A) and USB (up to 500mA). With the 入SYS。 DCM logic input set high, the DC input is in adapter DCM引脚具有一个内部连接至DC的二极管，如图1所示。 mode and the DC input current limit is set by the resisfrom IDC to GND (RIDC). Calculate RIDC accordtance 为防止电流从DCM经内部二极管流至DC输入，DCM的 ing to the following equation: 驱动电压不能大于DC。图3所示电路中，通过一个简单的 MOSFET和DCM端的外部电阻即可防止电流从DCM经内 RIDC = 6000V/IDC-MAX 部二极管流至DC。图3中的电路允许微处理器在任何时候 With the DCM logic input set low, the DC input current 将MOSFET的栅极驱动至任何状态。 limit is internally programmed to 500mA or 100mA as set by the IUSB logic input. With the IUSB logic input set high, the DC input current limit is 500mA and the DC input delivers current to SYS through the step-down regulator. With the IUSB logic input set low, the DC input current limit is 100mA. In this 100mA mode, the step-down regulator is turned off and its high-side switch operates as a linear regulator with a 100mA current limit. The linear regulator’s output is connected to LX and its output current flows through the inductor into CS and finally to SYS. ______________________________________________________________________________________ USB和适配器供电系统 the DC power-OK output feature is not required, connect DOK to ground. UOK is an open-drain, active-low output that indicates the USB input power status. UOK is low when a valid source is connected at USB. The source at USB is valid when 4.1V < VUSB < 6.6V. If the USB power-OK output feature is not required, connect UOK to ground. MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y The DCM pin has an internal diode to DC as shown in Figure 1. To prevent current from flowing from DCM through the internal diode and to the DC input, DCM cannot be driven to a voltage higher than DC. The circuit of Figure 3 shows a simple MOSFET and resistor on DCM to prevent any current from flowing from DCM through the internal diode to DC. This circuit of Figure 3 allows a microprocessor to drive the gate of the MOSFET to any state at any time. An alternative to the simple MOSFET and resistor on DCM as shown in Figure 3 is to place a 1M resistor in 图3中MOSFET和DCM端电阻的一种替代方案是在DCM输 series with the DCM input to the microprocessor. The 入与微处理器之间串联一个1MΩ电阻。微处理器监测DOK microprocessor can then monitor the DOK output and 输出，确保在DOK为高电平时DCM仍然为低电平。如果 make sure that whenever DOK is high DCM is also low. DCM的驱动电压高于DC，1MΩ串联电阻把从DCM经内部 In the event that DCM is driven to a higher voltage than 二极管流至DC的电流限制在几个μA。 DC, the 1M series resistance limits the current from DCM through the internal diode to DC to a few µA. USB输入—线性稳压器 如果USB输入有效、DC输入无效，SYS和电池充电电流均 USB Input—Linear Regulator 由连接在USB和SYS之间的低压差线性稳压器提供。SYS If a valid USB input is present with no valid DC input, 的稳压特性与DC输入条件下相同(图4所示)。电池充电器 current for SYS and battery charging is supplied by a 将从SYS获取所能提供的电流，但不会超出最大允许的 low-dropout linear regulator connected from USB to USB电流。如果USB和DC输入均有效，则由DC输入供电。 SYS. The SYS regulation voltage shows the same char最大USB输入电流由IUSB输入的逻辑状态设置为100mA acteristic as when powering from the DC input (see 或500mA。 Figure 4). The battery charger operates from SYS with any extra available current, while not exceeding the 电源监测器输出(UOK、DOK) maximum-allowed USB current. If both USB and DC DOK为漏极开路、低电平有效输出，指示DC输入电源的 inputs are valid, power is only taken from the DC input. 状态。若USB引脚没有电源，当4.15V < V DC < 16V时，DC The maximum USB input current is set by the logic 电源被认为有效且DOK驱动至逻辑低电平；若USB电源 state of the IUSB input to either 100mA or 500mA. 也有效，当4.45V < VDC < 16V时，DC电源被认为有效且 Power Monitor Outputs (UOK, DOK) DOK驱动至逻辑低电平。USB输入有效时，如果最小DC DOK is an open-drain, active-low output that indicates 电压值较高，则有利于输入电源之间的低噪声转换。如果 the DC input power status. With no source at the USB 不需要DC电源就绪输出，可将DOK连接至地。 pin, the source at DC is considered valid and DOK is UOK为漏极开路、低电平有效输出，指示USB输入电源的 driven low when: 4.15V < VDC < 16V. When the USB 状态。USB连接有效电源时，UOK为逻辑低电平；4.1V < voltage is also valid, the DC source is considered valid < 6.6V时，USB电源有效。如果不需要USB电源就绪 VUSBDOK and is driven low when: 4.45V < VDC < 16V. The 输出，可将UOK连接至地。 higher minimum DC voltage with USB present helps guarantee cleaner transitions between input supplies. If 2A单节Li+电池DC-DC充电器， Both the UOK and the DOK circuitry remain active in 用于USB和适配器供电系统 thermal overload, USB suspend, and when the charger VSYSREG VBATREG MAX8903_ VSYS IBAT x RON VSYSMIN VBAT VCEN = 0V VDC AND/OR VUSB = 5.0V 图4．SYS跟随VBAT至最小系统电压 is disabled. DOK and UOK can also be wire-ORed UOK和DOK电路在热过载、USB挂起以及充电器被禁止时 together to generate a single power-OK (POK) output. 均保持有效工作状态。也可以将DOK和UOK“线或”连接， Thermal Limiting 构成一路电源就绪(POK)输出。 When the die temperature exceeds +100°C, a thermal limiting circuit reduces the input current limit by 热保护 5%/°C, bringing the charge current to 0mA at +120°C. Since 当管芯温度超过+100°C时，热保护电路将按照5%/°C降低 the system load gets priority over battery charging, the 输入电流门限，温度达到+120°C时充电电流为0mA。由于 battery charge current is reduced to 0mA before the 系统负载供电的优先级高于电池充电，电池充电电流会在 input limiter drops the load voltage at SYS. To avoid 输入限制器拉低SYS负载电压之前降至0mA。为避免错误 false charge termination, the charge termination detect 地结束充电，该模式下的充电终止检测功能被禁用。如果 is disabled in this mode. If the junction temperfunction 结温上升至+120°C以上，不会从DC或USB吸收电流，并 ature rises beyond +120°C, no current is drawn from 且VSYS调节到低于V BAT 50mV。 DC or USB, and VSYS regulates at 50mV below VBAT. 系统电压切换 System Voltage Switching DC输入 DC Input 当由DC输入充电时，如果电池电压高于最小系统电压，SYS When charging from the DC input, if the battery is 则被连接至电池。电流供给SYS和电池，可以达到最大设 above the minimum system voltage, SYS is connected 置值。降压转换器输出电流检测和充电电流检测所提供的 to the battery. Current is provided to both SYS and the 反馈确保电流环路需要较低的输入电流。当从DC供电时， battery, up to the maximum program value. The step这种方法的优势在于功耗主要取决于降压调节器的效率， down output current sense and the charger current 因为SYS和BAT之间的压降非常低。此外，电池能够吸收 sense provide feedback to ensure the current loop 负载瞬变的影响，使SYS电压波动最小。若DC和USB输入 demanding the lower input current is satisfied. The 均有效，则DC输入优先级较高，由它提供输入电流，同 advantage of this approach when powering from DC is that power dissipation is dominated by the step-down 时USB输入被关闭。 regulator efficiency, since there is only a small voltage 电池完成充电后，充电器关闭，SYS负载电流由DC输入提 drop from SYS to BAT. Also, load transients can be 供，SYS电压稳定在VSYSREG。电池电量下降到重新启动 absorbed by the battery while minimizing the voltage 充电的门限时，再次打开充电器。如果负载电流超出输 disturbance on SYS. If both the DC and USB inputs are 入门限，SYS电压降至电池电压，并且SYS和BAT之间的 valid, the DC input takes priority and delivers the input 50mΩ PMOS开关导通，以支持更大的负载电流。一旦负 current, while the USB input is off. 载电流低于输入电流门限，SYS和BAT之间的开关被关闭。 After the battery is done charging, the charger is turned 如果撤除有效的DC电源，则50mΩ PMOS也将导通。 off and the SYS load current is supplied from the DC input. The SYS voltage is regulated to VSYSREG . The USB输入 charger turns on again after the battery drops to the 由USB输入充电时，DC输入降压调节器关闭，连接在USB restart threshold. If the load current exceeds the input 和SYS之间的线性稳压器向系统供电并向电池充电。如果 limiter, SYS drops down to the battery voltage and the 电池电压高于最小系统电压，SYS供电电压被连接至电池。 50m SYS-to-BAT PMOS switch turns on to supply the USB输入向SYS负载供电，并利用额外的电流为电池充电， extra load current. The SYS-to-BAT switch turns off again 总电流不会超过最大允许的USB电流。电池能够吸收负载 once the load is below the input current limit. The 50m 瞬变的影响，使SYS电压波动最小。电池充电结束或充电 PMOS also turns on if valid DC input power is removed. 器被禁止时，SYS电压稳定在VSYSREG。如果USB和DC输 入均有效，则只从DC输入供电。 ______________________________________________________________________________________ 17 17 MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 USB和适配器供电系统 用于USB和适配器供电系统 表2．输入限制器控制逻辑 Table 2. Input Limiter Control Logic POWER SOURCE AC Adapter at DC Input IUSB USUS DC STEP-DOWN OUTPUT CURRENT LIMIT DOK UOK DCM*** L X H X X 6000V/RIDC L X L L L 100mA L X L H L 500mA L X L X H USB suspend USB INPUT CURRENT LIMIT Lesser of 1200V/RISET and 6000V/RIDC USB input off. DC input has priority. USB Power at DC Input USB Power at USB Input, DC Unconnected DC and USB Unconnected MAXIMUM CHARGE CURRENT** Lesser of 1200V/RISET and 100mA Lesser of 1200V/RISET and 500mA 0 100mA Lesser of 1200V/RISET and 100mA H L X L L H L X H L H L X X H USB suspend Lesser of 1200V/RISET and 500mA 0 H H X X X No USB input 0 No DC input 500mA **Charge current cannot exceed the input current limit. Charge may be less than the maximum charge current if the total SYS load ** 充电电流不能超过输入电流门限，如果总的SYS负载电流超过输入限流，将控制充电电流低于最大充电电流。 exceeds the input current limit. *** DCM (阳极)与DC (阴极)之间接有一个内部二极管，如图1所示。如需通过μP设置DCM电平，需采用一个MOSFET进行隔离，如图3 ***There =is 无关。 an internal diode from DCM (anode) to DC (cathode) as shown in Figure 1. If the DCM level needs to be set by a µP, use 所示。X a MOSFET for isolation as shown in FIgure 3. USB挂起 驱动USUS为逻辑高电平、DCM为逻辑低电平将关闭充电 USB Input 器和SYS输出，并将输入电流降至170μA，进入USB挂起 When charging from the USB input, the DC input stepdown regulator turns off and a linear regulator from 模式。请参考表2所示的设置。 USB to SYS powers the system and charges the battery. If the battery is greater than the 充电使能(CEN) minimum system CEN为逻辑低电平时，充电器开启；CEN为逻辑高电平 voltage, the SYS voltage is connected to the battery. 时，充电器关闭。CEN不影响SYS输出。许多系统中，不 The USB input then supplies the SYS load and charges 需要系统控制器(通常为微处理器)关闭充电器工作，因为 the battery with any extra available current, while not exceeding the maximum-allowed USB current. Load MAX8903_智能电源选择器能够独立地管理充电和适配器/ transients can be absorbed by the battery while mini电池电源的关断。这种情况下，CEN可以接地。 mizing the voltage disturbance on SYS. When battery charging is completed, or the charger is disabled, SYS is regulated to VSYSREG. If both USB and DC inputs are valid, power is only taken from the DC input. USB Suspend Driving USUS high and DCM low turns off charging as well as the SYS output and reduces input current to 170µA to accommodate USB suspend mode. See Table 2 for settings. 18 18 软启动 为了防止能够导致USB或交流适配器电源不稳定的输入瞬 Charge Enable (CEN) 变，输入电流和充电电流的变化率均受限。当一路输入电 When CEN is low, the charger is on. When CEN is high, 源有效时，SYS电流从零开始上升到所设置的电流门限， the charger turns off. CEN does not affect the SYS out通常时间为50μs。这也意味着，如果DC在USB之后有效， put. In many systems, there is no need for the system controller (typically a microprocessor) to disable the SYS电流将在USB切换到DC输入之前降至零。在某个工作 charger, because the MAX8903_ smart power selector 点，SYS可能无法支持负载供电，切换至BAT。当V SYS < circuitry independently manages charging and V BAT时，将切换至BAT。该门限具体取决于SYS电容和 adapter/battery power hand-off. In these situations, CEN SYS负载。SYS电流随后从零上升到所设置的电流，只要 may be connected to ground. SYS负载电流小于所设置的电流门限，SYS即可支持负载。 Soft-Start To prevent input transients that can cause instability in the USB or AC adapter power source, the rate of change of the input current and charge current is limited. When an input source is valid, SYS current is ramped from zero to the set current-limit value in typically 50µs. This also means that if DC becomes valid after USB, the SYS current limit is ramped down to zero before switching from the USB to DC input. At some point, SYS is no longer able to support the load and may switch over to ______________________________________________________________________________________ USB和适配器供电系统 capabilities of a 100mA or 500mA USB input, or overloads an AC adapter. See Figure 5. When VBAT is below VBATPQ, the charger enters prequal mode and the battery charges at 10% of the maximum fast-charge rate until the voltage of the deeply discharged battery recovers. When the battery voltage reaches VBATREG and the charge current drops to 10% of the maximum fast-charge current, the charger enters the DONE state. The charger restarts a fast-charge cycle if the battery voltage drops by 100mV. 当VBAT低于VBATPQ时，充电器进入预充模式，以最大快 Charge Termination 充速率的10%为电池充电，直到过放电电池恢复正常。当 When the charge current falls to the termination thresh时，充电电流下降到最大快充电流 电池电压达到V the charger is in voltage mode, chargold (ITERM) andBATREG 的10%，充电器进入DONE状态。当电池电压跌落100mV ing is complete. Charging continues for a brief 15s 时，充电器将重新启动快充过程。 top-off period and then enters the DONE state where charging stops. 充电终止 falls to ITERM as a result of Note that if charge current 当充电电流降至终止门限(I TERM)并且充电器处于恒压模式 the input or thermal limiter, the charger does not enter 时，完成充电。充电过程将持续短暂的15s浮充周期，然 DONE. For the charger to enter DONE, charge current 后进入DONE状态，充电结束。 must be less than ITERM, the charger must be in volt注意，若充电电流因为输入限流或热保护下降至I TERM age mode, and the input or thermal limiter must not，充 be 电器不会进入DONE状态。若要充电器进入DONE状态，充 reducing charge current. 电电流必须低于ITERM并且充电器必须处于恒压模式、输入 Charge Status Outputs 限流或热保护电路没有降低充电电流。 Charge Output (CHG ) 充电状态指示输出 CHG is an open-drain, active-low output that indicates charger status. CHG is low when the充电指示输出(CHG) battery charger is in its prequalification and fast-charge states. CHG goes CHG为漏极开路、低电平有效输出，用于指示充电器状态。 high impedance if the thermistor causes the charger to 当电池充电器处于预充和快充状态时，CHG为低电平。如 go into temperature suspend mode. 果热敏电阻检测使充电器进入热保护状态，CHG将变为高 阻态。 When used in conjunction with a microprocessor (µP), connect a pullup resistor between CHG and the logic 与微处理器(μP)配合使用时，在CHG和逻辑I/O电压之间连 I/O voltage to indicate charge status to the µP. 接一个上拉电阻，为μP提供充电状态指示。此外，CHG可 Alternatively, CHG can sink up to 20mA for an LED 吸收最大20mA的电流，能够用于LED充电指示。 charge indicator. 故障指示输出(FLT) Fault Output (FLT) FLT为漏极开路、低电平有效输出，用于指示充电器状态。 FLT is an open-drain, active-low output that indicates 电池充电器进入故障状态并且充电定时器超时的情况下， charger status. FLT is low when the battery charger has FLT为低电平。当充电器处于预充状态的时间超过33分钟 entered a fault state when the charge timer expires. 或充电器处于快充状态的时间超过660分钟时，可能发生 This can occur when the charger remains in its prequal 这种情况(图6所示)。为了退出故障状态，可以触发CEN或 state for more than 33 minutes or if the charger remains 重新接通输入电源。 in fast-charge state for more than 660 minutes (see 6). To exit this fault state, toggle CEN or remove Figure 与微处理器(μP)配合使用时，在FLT和逻辑I/O电压之间连 and reconnect the input source. 接一个上拉电阻，为μP提供充电状态指示。此外，FLT可吸 When used in conjunction with a microprocessor (µP), 收最大20mA的电流，能够用于LED充电指示。如果不需要 connect a pullup resistor between FLT and the logic I/O FLT输出，可将FLT接地或浮空。 voltage to indicate charge status to the µP. Alternatively, FLT can sink up to 20mA for an充电定时器 LED fault 故障定时器可避免电池无限制地充电。预充和快充故障定 indicator. If the FLT output is not required, connect FLT to ground or leave unconnected. 时器由CT端的外接电容(C CT)设置。 2A单节Li+电池DC-DC充电器， 用于USB和适配器供电系统 果RISET通过一个开关突然改变，则没有di/dt限制。 Battery Charger While a valid input source is present, the battery charg电池充电器 er attempts to charge the battery with a fast-charge 存在有效的输入电源时，电池充电器将尝试以快充电流为 current determined by the resistance from ISET to 电池充电，电流由ISET与GND之间的电阻确定，根据下式 GND. Calculate the RISET resistance according to the 计算R ISET电阻： following equation: = 1200V/I CHGMAX 1200V/I RISET =RISET CHGMAX 监测充电电流 Monitoring Charge Current ISET和GND之间的电压代表电池充电电流，可用于监测电 The voltage from ISET to GND is a representation of the 池的充电电流。1.5V电压对应于最大快充电流。 battery charge current and can be used to monitor the current charging the battery. A voltage of 1.5V repre必要时，充电器可自动降低充电电流，以防SYS电压跌落。 sents the maximum fast-charge current. 因此，USB供电时充电器不会以超出100mA或500mA电流 If necessary, the charge current is reduced automati向电池充电，也不会造成交流适配器过载，请参考图5。 cally to prevent the SYS voltage from dropping. Therefore, a battery never charges at a rate beyond the MONITORING THE BATTERY CHARGE CURRENT WITH VISET 1.5 VISET (V) 0 DISCHARGING 0 1200V/RISET BATTERY CHARGING CURRENT (A) Figure 5. Monitoring the Battery Charge Current with the 图5．利用ISET和GND之间的电压监测电池充电电流 Voltage from ISET to GND ______________________________________________________________________________________ 19 19 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y BAT. The switchover to BAT occurs when VSYS < VBAT. This threshold is a function of the SYS capacitor size and SYS load. The SYS current limit then ramps from zero to the set current level and SYS supports the load again as long as the SYS load current is less than the set current limit. When the charger is turned on, the charge current ramps from 0A to the ISET current value in typically 1.0ms. Charge current also soft-starts when transitioning to fastcharge from prequal, when the input power source is switched between USB and DC, and when changing the 充电器开启时，充电电流从0A上升到ISET设置的电流，通 USB charge current from 100mA to 500mA with the IUSB 常时间为1.0ms。当从预充进入快充状态、输入电源在USB logic input. There is no di/dt limiting, however, if RISET is 和DC之间切换、IUSB逻辑输入将USB充电电流从100mA changed suddenly using a switch. 变为500mA时，充电电流也会进入软启动过程。然而，如 MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 电器，用于 USB和适配器供电系统 用于USB和适配器供电系统 NOT READY DOK = HIGH IMPEDANCE = HIGH IMPEDANCE = HIGH IMPEDANCE ICHG = 0mA UOK AND/OR DOK = LOW CEN = 0 RESET TIMER EQUALIFICATION AND/OR DOK = LOW CHG = LOW = HIGH IMPEDANCE 0 < VBAT < VBATPQ CHG ≤ ICHGMAX/10 V 0 CEN = HI OR REMOVE AND RECONNECT THE INPUT SOURCE(S) ANY STATE TOGGLE CEN OR REMOVE AND RECONNECT THE INPUT SOURCE(S) TIMER > tPREQUAL VBAT < VBATPQ - 180mV RESET TIMER TIMER > tTOP-OFF UOK OR DOK PREVIOUS STATE CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE DONE K AND/OR DOK = 0 = HIGH IMPEDANCE = HIGH IMPEDANCE + VRSTRT < VBAT < VBATREG ICHG = 0mA Timer indefie con- PREQUALIFICATION UOK AND/OR DOK = LOW CHG = LOW FLT = HIGH IMPEDANCE 0 < VBAT < VBATPQ ICHG ≤ ICHGMAX/10 ICHG > ITERM RESET TIMER TOP-OFF UOK AND/OR DOK = LOW CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE VBAT = VBATREG ICHG = ITERM ANY STATE TOGGLE CEN OR REMOVE AND RECONNECT THE INPUT SOURCE(S) TIMER > tPREQUAL FAULT UOK AND/OR DOK = LOW CHG = HIGH IMPEDANCE FLT = LOW ICHG = 0mA VBAT > VBATPQ RESET TIMER FAST-CHARGE TIMER > tFSTCHG UOK AND/OR DOK = LOW (TIMER SLOWED BY 2x IF CHG = LOW ICHG < ICHGMAX/2, AND VBATREG ) IMPEDANCE PAUSED IF ICHG < ICHGMAX/5 WHILE VBAT < FLT = HIGH VBATPQ < VBAT < VBATREG ICHG ≤ ICHGMAX ICHG < ITERM AND VBAT = VBATREG M AND THERMAL ANY CHARGING R OR INPUT LIMIT STATE NOT EXCEEDED; RESET TIMER THM OK THM NOT OK TOP-OFF TIMER RESUME TIMER SUSPEND K AND/OR DOK = LOW G = HIGH IMPEDANCE VBAT < VBATREG + VRSTRT RESET TIMER T = HIGH IMPEDANCE VBAT = VBATREG TEMPERATURE SUSPEND ICHG = ITERM ICHG = 0mA CEN = HI OR REMOVE AND RECONNECT THE INPUT SOURCE(S) UOK AND/OR DOK = LOW CEN = 0 RESET TIMER FAULT UOK AND/OR DOK = LOW CHG = HIGH IMPEDANCE V <V - 180mV FLT = LOW BAT BATPQ RESET TIMER = 0 ICHG = 0mA VBAT > VBATPQ RESET TIMER FAST-CHARGE AND/OR DOK = LOW CHG = LOW = HIGH IMPEDANCE TPQ < VBAT < VBATREG ICHG ≤ ICHGMAX NOT READY UOK AND DOK = HIGH IMPEDANCE CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE ICHG = 0mA TIMER > tFSTCHG (TIMER SLOWED BY 2x IF ICHG < ICHGMAX/2, AND PAUSED IF ICHG < ICHGMAX/5 WHILE VBAT < VBATREG) ICHG < ITERM AND VBAT = VBATREG AND THERMAL OR INPUT LIMIT NOT EXCEEDED; RESET TIMER VBAT < VBATREG + VRSTRT RESET TIMER TIMER > tTOP-OFF DONE UOK AND/OR DOK = 0 CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE VBATREG + VRSTRT < VBAT < VBATREG ICHG = 0mA 图6．MAX8903A充电状态流程图 Figure 6. MAX8903A Charger State Flow Chart Charge Timer CCTthe battery from charging indefiA fault timer tPREQUAL = 33prevents min × 0.15µFand fast-charge timers are connitely. The fault prequal trolled by the capacitance CCT at CT (CCT). tFST - CHG = 660min × 0.15µF tTOP -OFF = 15s (MAX 8903 A/D /H/ J/N / Y) C tTOP -OFF = 132min × CT (MAX 8903B/E / G) 0.15µF CCT tPREQUAL = 33min × 快充模式下，较重的系统负载或器件的自发热可能引起 0.15µF MAX8903_降低充电电流。这种情况下，如果充电电流下 CCT tFST - CHG = 660min × 降到所设置的快充电流的50%，快充定时器的计时速率将 0.15µF 降低2倍；如果充电电流下降到所设置的快充电流的20% tTOP -OFF = 15s (MAX 8903 A/D /H/ J/N / Y) 时，定时器进入挂起状态。如果充电器使BAT电压达到 C (即充电器进入恒压模式)，快充定时器将不受任 VBATREG tTOP -OFF = 132min × CT (MAX 8903B/E / G) 0.15µF 何电流的影响。 20 ______________________________________________________________________________________ 20 _____________________________________________ 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 用于USB和适配器供电系统 USB和适配器供电系统 MAX8903A-E/G/H/J/N/Y CEN THERMISTOR CIRCUITRY VL VL MAX8903_ MAX8903B/MAX8903E/ MAX8903G ONLY 0.87 VL RTB ALTERNATE THERMISTOR CONNECTION 0.74 VL THERMISTOR DETECTOR COLD THM RTS 0.28 VL RTP RT 0.03 VL RT HOT ENABLE THM THM OUT OF RANGE DISABLE CHARGER ALL COMPARATORS 60mV HYSTERESIS GND 图7．热敏电阻监测电路 its input power from USB or DC. When input power is available from both USB and DC, VL热敏电阻输入(THM) takes power from THM输入在外部连接一个负温度系数(NTC)的热敏电阻， MAX8903A DSDC. C_MAX8903A DS 2012-6-26 12:56 22 VL is enabled whenever the input页voltage at USB 用于监测电池或系统温度。当热敏电阻温度超过所限制的 DC is greater than ~1.5V. VL does not turn off when or 3750 4250 范围时，充电器处于挂起模式。充电计时器为挂起状态， the input voltage is above the overvoltage threshold. 10 10 并将保持该状态而不产生故障指示。当热敏电阻恢复到限 Similarly, VL does not turn off when the charger is disabled (CEN = high). Connect a 1µF ceramic capacitor 定范围时，重新开始充电，充电定时器从停止处重新开始 10 10 from VL to GND. 计时。将THM接GND则禁用热敏电阻监测功能，表3所示 为不同热敏电阻的故障温度。 3.78 3.316 Table 3. Fault Temperatures for Different 表3．不同热敏电阻对应的故障温度 Thermistor β (K) 3000 3250 3500 RTB (kΩ) (Figure 7) 10 10 10 Resistance at +25°C (kΩ) 10 10 10 Resistance at +50°C (kΩ) 4.59 4.30 4.03 Resistance at 0°C (kΩ) Thermistor Input (THM) 25.14 27.15 Nominal Hot Trip Temperature (°C) 29.32 31.66 36.91 55 53 50 49 46 Nominal Cold Trip Temperature (°C) -3 -1 0 2 4.5 AX8903A-E/G/H/J/N/Y While in fast-charge mode, a large system load VL稳压器 or device self-heating may cause the MAX8903_ to reduce charge VL是一个5V线性稳压器，为MAX8903的内部电路供电， current. Under these circumstances, the fast-charge 并为BST电容充电。VL在外部为电池的热敏电阻提供偏 timer is slowed by 2x if the charge current drops below 置。VL由USB或DC输入电源供电，当USB和DC端均连接 50% of the programmed fast-charge level, and suspend电源时，VL由DC电源供电。当USB或DC的输入电压高于 ed if the charge current drops below 20% of the pro1.5V左右时，VL使能。输入电压高于过压门限时，VL不 grammed level. The fast-charge timer is not affected at 会关断。同样，当充电器关闭(CEN = 高电平)时，VL也不 any current if the charger is regulating the BAT voltage 会关断。在VL与GND之间连接一个1μF电容。 at VBATREG (i.e., the charger is in voltage mode). VL Regulator VL is a 5V linear regulator that powers the MAX8903’s internal circuitry and charges the BST capacitor. VL is used externally to bias the battery’s thermistor. VL takes 由于热敏电阻监测电路在THM和VL之间引入了一个外部 The THM input connects to an external negative tem偏置电阻(R TB，图7)，热敏电阻无需局限于10kΩ (+25°C时)。 perature coefficient (NTC) thermistor to monitor battery 只要偏置电阻等于热敏电阻在+25°C时的阻值，即可使用 or system temperature. Charging is suspended when 任何阻值的热敏电阻。例如，对于+25°C时10kΩ的热敏电 the thermistor temperature is out of range. The charge timers are suspended and hold their state but no fault is 阻，在R TB处使用10kΩ电阻；对于+25°C时100kΩ的热敏 indicated. When the thermistor comes back into range, 电阻，则使用100kΩ电阻。 charging resumes and the charge timer continues from 对于典型的10kΩ (+25°C时)热敏电阻和10kΩ RTB电阻，当 where off. Connecting THM to cold). GND disables the (too hot)it left or rises above 28.7k (too This corre热敏电阻下降到3.97kΩ以下(过热)或上升到28.7kΩ以上(过 thermistor monitoring function. Table 3 lists the fault sponds to a 0°C to +50°C range when using a 10k 冷)时，充电器进入温度挂起状态。相当于使用β为3500的 temperature of with different thermistors. NTC thermistor a beta of 3500. The general relation 10kΩ NTC热敏电阻，温度处于0°C至+50°C范围。热敏电 Since the thermistor monitoring circuit employs an exterof thermistor resistance to temperature is defined by 阻与温度的通用关系式由下式定义： the equation: nal following bias resistor from THM to VL (RTB, Figure 7), the thermistor is not limited only to 10k (at +25°C). Any 1 as long1 as the used resistance thermistor canβbe − T + 273°C value is C 298 ° equivalent the +25°C resistance. For RT to =R × e 25 thermistor’s example, with a 10k at +25°C thermistor, use 10k at where: RTB, and with a 100k at +25°C thermistor, use 100k . typical 10k (at in +25°C) thermistor andata tempera10k RTB resistance of the thermistor RFor T =a The resistor, the charger enters a temperature suspend ture T in Celsius the thermistor falls at below 3.97k = when The resistance in ofresistance the thermistor +25°C Rstate 2A单节Li+电池DC-DC充电器，用于 USB和适配器供电系统 25 ______________________________________________________________________________________ 21 b = The material constant of the thermistor, which typi21 cally ranges from 3000K to 5000K T = The temperature of the thermistor in °C Table 3 shows the MAX8903_ THM temperature limits The MAX power en mistor de tery is pr pull THM above 87 removed Continu Power Dissipat θJA MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器，用于 USB和适配器供电系统 (too hot) or rises above 28.7k (too cold). This corresponds to a 0°C to +50°C range when using a 10k NTC thermistor with a beta of 3500. The general relation of thermistor resistance to temperature is defined by the following equation: The MAX8903B/MAX8903E/MAX8903G implement the power enabled on battery detection function with the thermistor detector comparator as shown in Figure 7. If no battery is present, the absence of the thermistor allows RTB to pull THM to VL. When the voltage at the THM pin increases above 87% of VL, it is assumed that the battery has been removed and the system powers down. However, there is 2A单节Li+电池DC-DC充电器， 用于USB和适配器供电系统 1 1 β 式中： T + 273°C RT = R25 × e − 298°C RT = 温度为T (摄氏度)时，热敏电阻的阻值(Ω) where: RT25= = +25°C时，热敏电阻的阻值(Ω) The resistance in of the thermistor at temperaR ture T in Celsius β = 热敏电阻的材料常数，典型值处于3000K至5000K R 25 = The resistance in of the thermistor at +25°C T = 热敏电阻的检测温度(°C) b表3给出了不同热敏电阻材料常数对应的MAX8903_ = The material constant of the thermistor, which THM typically ranges from 3000K to 5000K 温度限制。 T有些设计可能选择其它热敏电阻温度限值。通过改变R = The temperature of the thermistor in °C TB， 3 shows the MAX8903_ THM temperature limits Table 用一个电阻与热敏电阻串联和/或并联，或使用β值不同 for different thermistor material constants. 的热敏电阻，都可以调节温度温度门限。例如，使用β值 为4250的热敏电阻，并联一个120kΩ的电阻，可以得到 Some designs might prefer other thermistor temperature +45°C的高温门限和0°C的低温门限。由于热敏电阻阻值 limits. Threshold adjustment can be accommodated by changing RTB, connecting a resistor in series and/or in 在0°C左右时远远高于+50°C对应的阻值，并联一个大电 parallel with the thermistor, or using a thermistor with dif阻可以降低低温门限，而对高温门限的降低很小。相反， ferent b. For example, a +45°C hot threshold and 0°C 串联一个小电阻可以提升高温门限，而对低温门限的提升 cold threshold can be realized by using a thermistor 很小。加大R TB可降低低温门限和高温门限，减小RTB则会 with a b of 4250 提高两个门限。 and connecting 120k in parallel. Since the thermistor resistance near 0°C is much higher than it 值得注意的是只要有效电源连接至DC或USB，即使禁止 is near +50°C, a large parallel resistance lowers the 充电时(CEN = 高电平)，由于VL有效，热敏电阻将始终流 cold threshold, while only slightly lowering the hot 过偏置电流。使用10kΩ热敏电阻，且VL采用10kΩ上拉电 threshold. Conversely, a small series resistance raises 阻时，会产生额外的250μA负载。如果选择100kΩ热敏电 the hot threshold, while only slightly raising the cold 阻和100kΩ上拉电阻，该负载可降至25μA。 threshold. Raising RTB lowers both the cold and hot thresholds, while lowering RTB raises both thresholds. 电池检测的供电使能控制 Note that since VL is active whenever valid input power 电池检测功能的供电使能控制允许MAX8903B/MAX8903E/ is connected at DC or USB, thermistor bias current MAX8903G在施 加/移除电池时自动使能/禁用USB和DC flows at all times, even when charging is disabled (CEN 电源输入。该功能采用电池组的集成热敏电阻作为检测 = high). When using a 10k thermistor and a 10k 元 件，to 判断 时 施results 加 或 移in除an 电 池。 利 用 该250µA 功 能，load. 基于 pullup VL,何this additional MAX8903B/MAX8903E/MAX8903G的系统可在电池移除 This load can be reduced to 25µA by instead using a 时关断，而与USB或DC电源输入是否有外部电源无关。 100k thermistor and 100k pullup resistor. MAX8903B/MAX8903E/MAX8903G在热敏电阻检测比较 Power Enable on Battery Detection 器上使用电池检测供电使能控制的电路如图7所示。如果 The power enabled on battery detection function allows 没有链接电池，则不存在热敏电阻，THM将通过RTB上拉 the MAX8903B/MAX8903E/MAX8903G to automatically 至VL。当THM的引脚电压上升到VL的87%以上时，则认 enable/disable the USB and DC power inputs when the 为电池已经被移除，系统关断。也可以完全旁路该热敏电 battery is applied/removed. This function utilizes the 阻检测电路，这种情况下，允许系统在电池移除后继续采 battery pack’s integrated thermistor as a sensing mech用外部电源供电。如果将THM引脚连接至GND (THM端 anism to determine when the battery is applied or 的电压低于VL的3%)，则禁用热敏电阻检测功能，系统不 removed. With this function, MAX8903B/MAX8903E/ 会响应热敏电阻输入的变化。这种情况下，假定系统自身 MAX8903G-based systems shut down when the battery 具有温度检测功能，当温度超出安全充电范围时，停止由 is removed regardless of whether external power is CEN输入引起的充电状态变化。 available at the USB or DC power inputs. 22 22 功耗 表4. 封装热特性 28-PIN 4mm x 4mm THIN QFN SINGLE-LAYER PCB MULTILAYER PCB 1666.7mW 2286mW Derate 20.8mW/°C above +70°C Derate 28.6mW/°C above +70°C θJA 48°C/W 35°C/W θJC 3°C/W 3°C/W Continuous Power Dissipation 最小SYS输出电容 also the option to bypass this thermistor sensing option 根据MAX8903_版本的不同，SYS负载调整率为25mV/A或 completely, and so retain the ability to remove the battery 40mV/A。25mV/A版本增大了反馈环路增益，因而具有更 and let the system continue to operate with external power. If好的负载调整特性。为确保具有较高增益的反馈环路稳定 the THM pin is tied to GND (voltage at THM is below 3% 工作，需使用一个较大的SYS输出电容。具有25mV/A SYS of VL), the thermistor option is disabled and the system does not respond to the thermistor input. In those cases, it 负载调整率的器件需要22μF SYS输出电容，而具有40mV/A is assumed that the system has its own temperature sensSYS负载调整率的器件仅需要10μF SYS输出电容。关于 ing, and halts changing through CEN when the temperaMAX8903_不同版本的更多信息，请参见表6。 ture is outside of the safe charging range. DC-DC降压调节器的电感选择 Minimum SYS Output Capacitor MAX8903_的控制架构需使用一个1.0μH至10μH外部电感 Based on the version of the MAX8903_, the SYS load (LOUT)，以确保正常工作。本节对控制架构和电感选择进 regulation is either 25mV/A or 40mV/A. The 25mV/A ver行了说明。表5给出了典型应用的推荐电感选择。如在针 achieve better load regulation by increasing the sions 对特定应用选择最佳电感的计算过程中需要帮助，请参 feedback loop gain. To ensure feedback stability with 见以下网址的电子表格：china.maxim-ic.com/design/ this higher gain, a larger SYS output capacitor is tools/calculators/files/MAX8903-INDUCTORrequired. Devices with 25m/V SYS load regulation DESIGN.xls。 require 22µF SYS output capacitor whereas devices )的 MAX8903 DC-DC降压调节器采用恒定开关频率(f with 40m/V only require 10µF. See Table 6 for SW more information about the various versions of the 控制架构，当输入电压降低至接近输出电压时，采用高 MAX8903_. 占空比工作方式，受最小关断时间(tOFFMIN)的限制，器件 可以工作在低于fSW的频率。工作在高占空比条件时，调 Inductor Selection for 节器采用具有最小关断时间tOFFMIN的峰值电流控制架构。 Step-Down DC-DC Regulator )的 类似地，当输入电压较大时，受最小导通时间(t The MAX8903_'s control scheme requires an ONMIN external ，此时调节器采用最小导通 限制，工作频率无法达到f SW inductor (LOUT) from 1.0µH to 10µH for proper opera时间固定的谷电流控制架构。 tion. This section describes the control scheme and the considerations for inductor selection. TableOUT 5 ，在输 shows fSW = 4MHz的MAX8903器件版本具有最小的L recommended inductors for typical applications. For 入电压较低(5V或9V)时具有较高效率。对于输入电压较高 assistance with calculations needed to select the = 1MHz的MAX8903G因其更高的效率 (12V)的应用，f SWthe optimum inductor for a given application, refer to the 而成为最佳选择。 spreadsheet at: www.maxim-ic.com/tools/other/ ______________________________________________________________________________________ (( ( )) ) (( )) (( ( )) ) MAX8903A-E/G/H/J/N/Y offer the the offer with low low with use high high use = 1MHz 1MHz = cy. cy. minimum inimum lowest ee lowest tain ffSW tain SW an offoffss an ctor ripripctor enters rr enters currentcurrentty factor factor ty current current A in in the the A he maxie maxiherefore herefore )) 2A单节Li+电池DC-DC充电器， 用于USB和适配器供电系统 ,, A单节Li+电池DC-DC充电器，用于 USB和适配器供电系统 ements ments aa switchtt switcheases to to eases peration peration due ffSW SW due igh duty gh duty and MIN and MIN he input input he minimum minimum comes omes aa (( -E/G/H/J/N/Y E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 903A-E/G/H/J/N/Y 03A-E/G/H/J/N/Y 03A-E/G/H/J/N/Y 8903A-E/G/H/J/N/Y VSYS(MAX × tOFF 1A)) designs. from (0.2 for (2A Ioff-time SW operation OFFKis0.45) (3) occurs and the device canfSW operate at less than fSW due voltage is too high to allow due tooperation minimum where tOFF the minimum obtained from (1). SDLIM a value near the output voltage, high duty cycle to minimum off-time (tONMIN ) the constraints. Inbecomes high dutya LOUT _ MIN _ TOFF = VSYS(MAX) × tOFF ), regulator on-time constraints (t OFFMIN ONMIN to minimum off-time (t ) constraints. In high duty ), the regulator becomes a on-time constraints (t L = OFFMIN ONMIN (3) occurs and theon-time device can operate at less fSW due OUT _ MIN _ TOFF K ISDLIM ×VSYS V tON and cycle operation, the regulator operates withthan tOFFMIN VSYS tOFF fixed minimum valley regulator. )) −−(−MAX ((MIN )) × K ISDLIM )× fixed minimum on-time valley current current regulator. VDC DC=(((MAX MAX SYS MIN ON and cycle operation, the regulator with In tOFFMIN DC MAX ) ×VSYS (MIN ) × tON to minimum off-time (tOFFMIN )operates constraints. high duty (4) = LLOUTL_OUT (4) _ MIN _ T aVersions peak current regulation. Similarly, when the input MIN t = OUT __ MIN MIN __ ttON of the MAX8903 with ffSW = 4MHz offer the OUT ON OFF × K I × I K aVersions peak current regulation. Similarly, when the input ON SDLIM SDLIM and cycle operation, the regulator operates with t SW of the MAX8903 with = 4MHz offer the OFFMIN × I K SW SDLIM from (1). due to minimum where tOFF is the minimum off-time obtained voltage isLtoo high to allow fSW operation SDLIM smallest while delivering good efficiency with low operation due tothe minimum where tOFF is the minimum off-time obtained from (1). voltage high to allow fSWSimilarly, OUT a peak iscurrent regulation. when input smallest Ltoo delivering good efficiency with low OUT while on-time constraints (t ), the regulator becomes a ONMIN input voltages (5V or 9V). For applications that use high is maximum input voltage, V is where V on-time constraints (t ), the regulator becomes a DC(MAX) SYS(MIN) ONMIN where V input voltages (5V or 9V). For applications that use high is maximum input voltage, V operation due to minimum is the minimum obtained from where tOFF voltage is too high to allow fSW DC(MAX) SYS(MIN) × VDCoff-time t (1). is DC(MAX) fixed minimum on-time valley current regulator. ) −− V (MIN ) SYS(MIN) ×istON VDC((MAX VSYS = 1MHz the oninput voltages (12V), the MAX8903G with the minimum charger output voltage, and ttON fixed on-time valley regulator. MAX ) SYS ( MIN ) ON (4) on-time constraints (tONMIN ),current the regulator becomes a = L SW ON = 1MHz is the oninputminimum voltages (12V), the MAX8903G with ffSW the minimum charger output voltage, and SW ON _ MIN _ tON = (4) LOUT Versions of the MAX8903 with fSWregulator. = 4MHz offer the ISDLIM is best because its efficiency. time high as given by the following OUT _ MINinput _ tON voltage, −× VDC(MAX tON fixed on-time valleyof current Versions the MAX8903 with offer the is the theminimum bestofchoice choice because of its fhigher higher efficiency. time at at high input voltage, asK by (MINthe ) × following ×VSYS K)given ISDLIM SW = 4MHz smallest L while delivering good efficiency with low (4) equation: = L OUT equation: OUT _ MIN _ t For a given maximum output voltage, the minimum smallest L while delivering good efficiency with low ON OUT For a given maximum output voltage, the minimum Versions of the(5V MAX8903 with fSW = 4MHz offer the K × voltage, ISDLIM VSYS(MIN) is where VDC(MAX) is maximum input input voltages or 9V).condition For applications thatthe use high inductor current occurs at lowest where VDC(MAX) is maximum input voltages or delivering 9V).condition For applications that use high input voltage, VSYS(MIN) is inductor ripple current occurs at the lowest smallest Lripple while good efficiency with low tON V OUT (5V 1 = 1MHz is the oninput voltages (12V), the MAX8903G with f the minimum charger output voltage, SYS MIN ( ) V SW SYS((MIN MIN 1 and input voltage that allows the regulator to maintain ffSW SYS )) × 1 = 1MHz input voltages (12V), the For MAX8903G with fSW use the minimum charger output voltage, and t (5) t = t if ,the ≤ t ON where V input voltages (5V or 9V). applications that high is maximum input voltage, V is ON ONMIN ONMIN SW (5) t = t if × , t on≤ t input voltage that allows the regulator to maintain DC(MAX) SYS(MIN) 1is SW ON ONMINvoltage, ONMIN is the best choice because of its higher efficiency. time at high input as given by the following ON ONMIN ONMIN V f DC MAX SW ( ) operation. If the minimum input voltage dictates an offtO is the best choice because of its higher efficiency. time at high input voltage, as given by the following O V f DC MAX SW ( ) O 1MHz is the oninput voltages (12V), the MAX8903G with fSW = an the minimum charger output voltage, and t DC MAX SW ( ) operation. If the minimum input voltage dictates offON ( ) equation: (( by)) the following For given maximum output the minimum ,, then minimum inductor riptime than ttOFFMIN equation: then thevoltage, minimum inductor riptime less than is thea best choice because of the its higher efficiency. time at high input voltage, as given OFFMIN For aless given maximum output voltage, the minimum OFFMIN otherwise, 对于给定的输出电压最大值，若最小输入电压允许调节器 V inductor rippleoccurs currentjust condition occurs at the lowest otherwise, ple condition before the regulator enters 1 ((MIN )) O VSYS equation: VSYS SYS MIN inductor ripple currentjust condition occurs at the lowest ple condition occurs before the regulator enters O (MIN ) × SYS (MIN ) 11 O For a given maximum output voltage, minimum ttON = 工作频率，则输入电压最小时电感纹波电流最小。 保持f SW input voltage that allowsoperation. the regulator tothe maintain fSW 1 , minimum off-time To allow the currentfixed ) ×f 1 ≤ tONMIN (5) tON = tONMIN ON = ifV VSYS(MIN× ON input voltage that allows the regulator to maintain f fixed minimum off-time operation. To allow the current1 , tO SW (5) t = t if × ((MAX )) ) fSW inductor ripple condition occurs at OFFMIN the lowest VDC fSW ≤ tONMIN ON ONMIN VDC ，则 如果输入电压最小值限定的开关关断时间小于t DC MAX SW (MAX operation. If thecurrent minimum input voltage dictates an off( ) DC MAX SW mode regulator to provide a low-jitter, stable duty factor V t f 1 mode regulator to provide a low-jitter, stable duty factor V SYS MIN ( ) DC MAX SW ( operation. If the minimum input voltage dictates an off ) ( ) input voltage that allows the inductor regulator to maintain frip1 , O SW (5) tON = tONMIN if × ( ≤) tONMIN 调节器在即将进入固定最小关断时间工作模式时具有最小 inductor , then the minimum inductor time less thanthe tOFFMIN operation, minimum ripple current operation, the minimum inductor ripple current t The tion satura current DC rating of the (I ) VDC f (ISAT , then thevoltage minimum inductor riptime less than tOFFMIN otherwise, O tion current DC rating of (the The satura MAX)inductor operation. If the input dictates an offSAT) 否则 VSYS SAT 的电感纹波电流。为了使工作在电流模式的调节器具有低 ple condition occurs just before the regulator enters otherwise, (I )) minimum should be greater than 150mA in the 1SW (MIN ) step-down O ) output VSYS must be than the DC current L_RIPPLE_MIN ple condition occurs the regulator enters shouldjust bebefore greater than 150mA in ripthe (IL_RIPPLE_MIN 1( L_RIPPLE_MIN (MIN ) step-down O greater t = × , then the minimum inductor time less than t must be greater than the DC output current OFFMIN ON 抖动和稳定的占空比系数，在电感纹波电流处于最小值时 minimum off-time operation. To allow the currentfixed minimum inductor ripple current condition. The maxitON one-half =V ×maximum otherwise, fSW )) plus the ripple limit minimum off-time operation. To allow the currentfixed minimum inductor ripple current condition. The maxiDC(MAX V limit (I (ISDLIM plus one-half the ripple current, current, ple condition occurs just the regulator enters SDLIM 1 VSYS fSW (MIN ))) maximum O SDLIM mode regulatoroutput to provide abefore low-jitter, stable duty factor ( DC MAX )应大于150mA。由 电感的纹波电流最小值(I mum allowed inductance L is therefore OUT_MAX L_RIPPLE_MIN mum allowed output inductance L is therefore t = × as given by equation (6). OUT_MAX modeminimum regulator off-time to provide a low-jitter, stablethe duty factor ON OUT_MAX as given by equation (6). operation. To allow currentfixed operation, thethe minimum inductor ripple current VDCof fSW obtained using equations (1) below. 。 下面的式(1)和式(2)计算所允许的输出电感最大值L OUT_MAX (MAX tion current DC rating the) inductor (I The satura ) operation, thethe minimum inductor ripple current obtained using equations (1) and and (2) (2) below. mode regulator to provide a greater low-jitter, stable duty factor tion current DC rating of the inductor (ISAT The satura SAT) (I ) should be than 150mA in the IL L_RIPPLE_MIN RIPPLE MAX _ must be greater than the DC step-down output current (1) (I ) should be greater than 150mA in the IL RIPPLE MAX _ L_RIPPLE_MIN operation, the minimum inductor rippleThe current RIPPLE _ MAX IISAT rating > IISDLIM + must be greater than the step-down current (1) V minimum inductor ripple current maxiThe tion satura current DC of DC the inductor (Ioutput (6) 1 SAT) current, ((MAX ))condition. VSYS +the SAT >one-half SDLIM (6) ) plus maximum ripple limit (I SYS MAX SAT SDLIM )必须大于直流降压输出限流 电感饱和直流电流额定值(I SDLIM 2 minimum inductor ripple current condition. The maxi1 SAT SYS MAX ( ) t t = t if 1 − × ( ≤ , (I ) should be greater than 150mA in the ) plus one-half the maximum ripple current, limit (I L_RIPPLE_MIN OFFMIN OFFMIN 2 t tOFF = t if 1 − × ( ≤ , (1) SDLIM mum allowed output inductance L is therefore must be greater than the DC step-down output current ( OFF OFFMIN − V OFFMIN OUT_MAX ,, given fSW OFFMIN as by equation (6). inductance 值(I DC MIN ))Lcondition. mumOFF allowed output isOFFMIN therefore SDLIM)与二分之一最大纹波电流值之和，如式(6)所示。 (2) fSW Vcurrent minimum inductor ripple The maxiDC((((1) MINand SWbelow. as given by )equation (6). the maximum ripple current, DC MIN ) OUT_MAX obtained using the equations plus one-half limit (ISDLIM obtained using the equations (1) and (2) below. mum allowed output inductance LOUT_MAX is therefore where IL is the of ripple currents RIPPLE_MAX as given by equation (6). ILRIPPLE RIPPLE_MAX is the greater greater of_the the where IL RIPPLE_MAX MAXripple currents (1) otherwise, ILRIPPLE 否则 obtained using the equations and (2) below. MAX _ I > I + obtained from (7) and (8). (1) otherwise, VSYS((1) SAT SDLIM obtained from (7) and (8). (6) 1 MAX) ISAT > ISDLIM + (6) 2 (6) == tOFFMIN (((if 1 −V VSYS(MAX) × (1 ≤ tOFFMIN , ILRIPPLE 2 _ MAX (1) ttOFF == tOFFMIN if 1 −VSYS × fSW (1 ≤ tOFFMIN , , O ( ) MAX V OFF 1 O I > I + ( SYS MAX DC MIN ( ) V , O ( ) SYS MAX SAT SDLIM f V (6) 1 ttOFF = 1 − × SYS MAX ( ) V ×t −− DC(MIN) × SW SYS V 2 = 1 OFF SYS(((MAX MAX))) × tOFF OFF tOFF = tOFFMIN ( ≤ tOFFMIN , OFF if 1 − VDC(MIN) ×fSW (7) SYS MAX OFF IL = where IL is the greater of the ripple currents RIPPLE_MAX RIPPLE _ MIN _ T (7) IL = f VDC , ( ) DC MIN SW f V (MIN ) ) SW RIPPLE __ MIN MIN 为由式(7)和(8)计算得到的纹波电流中 其中，IL where ILRIPPLE_MAX is__ the ripple currents DC (MIN SW RIPPLE TTOFF OFFgreater ofLthe RIPPLE_MAX otherwise, OFF OUT L obtained from (7) and (8). OUT otherwise, OUT 数值较大的一个。 obtained from (7) andis(8). where ILRIPPLE_MAX the greater of the ripple currents ( where tOFF is V is SYS(MAX) ( = 为关断时间，V VSYS OFF SYS(MAX) where is the the off-time, off-time, V is 1maximum maximum charger charger otherwise, O tOFF SYS(MAX) (MAX ) 为充电器输出电压最大 其中，t OFF SYS(MAX) = obtained from (7) and (8). V O voltage, ) × 1 DC SYS(MAX is output tOFFand = ( V 1 −DC(MIN) ×t V VSYS × tOFF is minimum minimum DC input input voltvoltoutput voltage, and ((MAX )) −−− V SYS ((MIN (MAX tOFF = 1V−DC(MIN) × DC(MIN) V=DC DC MAX SYS MIN))) × tON ON × tOFF VSYS 为最小直流输入电压。 值，VDC(MIN) (7) DC (MAX ) V))SYS (MIN ON (8) (MAX ILRIPPLE IL = ) ) ffSW DC((MIN age. VV _ MIN _ T RIPPLE _ MIN _ T 1 (7) VSYS (8) MAX age.O = (7) OFF IL = ON IL = RIPPLE _ MIN _ T ( ) DC MIN SW RIPPLE _ MIN _ T L RIPPLE _ MIN _ T ON L ONOFF tOFF = 1 − U VSYS(MAX tOFF × LO LOUT UT )O× O U TT OUT (7) VDC V ttOFF )isf×SW ILRIPPLE _ MIN _ TOFF = (SYS MIN()MAX V × V maximum charger where tOFF isLthe off-time, SYS ( MAX ) OFF SYS(MAX) SYS(MAX )is maximum OFF LOUT = off-time, charger where tOFF isLthe (2) (2) =VSYS(MAX) OUT MAX PCB and Routing (2) output voltage,OUT and___MAX VDC(MIN) minimum DC input voltOUT MAX IIL _is VDCLayout tON PCB Layout and Routing RIPPLE __ MIN (MAX ) −− V SYS (MIN ) × output tvoltage, and V is minimum DC input voltL _ RIPPLE MIN DC(MIN) V Vand L _ RIPPLE _ MIN where is the off-time, V is maximum charger (8) DC ( MAX ) SYS ( MIN ) × tON SYS(MAX) Good design minimizes ground bounce voltage graIL = age. OFF RIPPLE _ MIN _ T (8) Good design minimizes ground bounce and voltage graON (8) IL = age. voltage, and VDC(MIN) is minimum DC input voltRIPPLE _ MIN _ Tplane, output ON OSYS UT (MIN −L × tON Vwhich V dients in the ground can result in instability DC ( MAX ) ) dients in the ground plane, which can result in instability L 为所允许的最大电感值。 其中，L O U T OUT_MAX where L is the maximum allowed inductance. (8) OUT_MAX VSYS(MAX tOFFinductance. ILRIPPLEerrors. = age. OUT_MAX is the maximum where LOUT_MAX allowed )× _ MIN _ The TON GND or connect VSYS(MAX ) × tOFF or regulation regulation errors. The GND and and PGs PGsLshould should connect to to Lsmall-sized Oand Uto T minimize OUT _ MAX = 为选取一个磁芯损耗符合要求且能够在指定f (2) To obtain a inductor with acceptable core SW工作频率 L = PCB Layout Routing the power-ground plane at only one point the To obtain a small-sized inductor with acceptable core I OUT _ MAX (2) L _ RIPPLE _ MIN PCB Layout and Routing the power-ground plane at only one point to minimize the V × t PCB布局和布线 ISYSRIPPLE (MAX ) _ MIN OFF 下保证无抖动稳定工作的小尺寸电感，可以首先设置适当 loss, while providing stable, operation at Good minimizes ground bounce and voltage graeffects of currents. Battery ground should Lavailable = L _jitter-free effectsdesign of power-ground power-ground currents. Battery ground should loss, while stable, jitter-free operation at the the picking an providing inductor in the the range range inductance OUT _ MAX Good design minimizes ground bounce and voltage grapicking an available inductor in inductance (2) 良好的布线设计有助于降低地电位的偏差和接地平面的电 PCB Layout and Routing I , the actual output inductance (L ), is advertised f 的纹波系数K，并在式(2)、(3)和(4)给出的范围内选取电感 dients in the ground plane, which can result in instability SW OUT connect directly to the power-ground plane. The ISET L _ RIPPLE _ MIN SW OUT connect directly to the power-ground plane. The ISET , the actual output inductance (L ), is advertised f SW OUTalso should also yieldedLOUT_MAX by equations equations (2), (3), and andallowed (4). LLOUT dients in the ground plane, which can result in instability should yielded by (2), (3), (4). is the maximum inductance. where OUT Good design minimizes ground bounce and voltage gra压梯度，这些因素会导致系统不稳定或稳压误差。GND和 obtained by appropriate factor is thean maximum allowed inductance. where LOUT_MAX or regulation errors. The GND andshould PGs should connect to 。Lripple 值，从而确定实际的输出电感L and IDC current-setting resistors connect directly OUT OUT不应低于表6列 obtained by choosing choosing appropriate ripple factor K, K, and and notobtain be lower lower than the the an minimum allowable inductance as or regulation errors. The GND andshould PGs should to and IDC current-setting resistors connect directly not be than minimum allowable inductance as dients in the ground plane, which can result inconnect instability PG仅通过一个点连接至功率地，使功率地电流的影响最 To a small-sized inductor with acceptable core the power-ground plane at only one point to minimize the ≥ 1A)的工作条件， 出的最小电感值。对于(2A ≥ I SDLIM is the maximum allowed inductance. where L To obtain a small-sized inductor withripple acceptable core OUT_MAX shown in Table 6. The recommended ripple factor ranges the power-ground plane at only one point to minimize the shown in Table 6. The recommended factor ranges or regulation errors. The GND and PGs should connect to 小。电池地应该直接连接到功率地。ISET和IDC电流设置 loss, while providing stable, jitter-free operation at the effects of power-ground currents. Battery ground should 推荐的纹波系数范围为(0.2 ≤ K ≤ 0.45)。 ______________________________________________________________________________________ 23 loss, while providing stable, jitter-free operation at the 1A)acceptable designs. from (0.2 afK Ksmall-sized 0.45) for (2Ainductor effects of power-ground currents. ground should 1A) designs. from (0.2 0.45) for (2A IISDLIM ______________________________________________________________________________________ 23 SDLIM To obtain with 23 the power-ground plane at only oneBattery pointplane. to minimize the , the______________________________________________________________________________________ actual output inductance (LOUTcore ), is advertised 电阻应直接连接到GND，避免电流误差。将GND直接连 SW connect directly to the power-ground The ISET advertised fSW, the actual output inductance (LOUT is connectofdirectly to the power-ground plane. Theshould ISET loss, jitter-free operation at ), the effects power-ground currents.should Battery ground (3) while (3) obtained byproviding choosing stable, an appropriate ripple factor K, and 接到IC下方的裸焊盘。在裸焊盘下方使用多个过孔接地， and IDC current-setting resistors connect directly VVSYS SYSinductance MAX OFF(LOUT obtained byfSW choosing an appropriate ripple factor K, ), and ((MAX )) ×× ttOFF and IDC directly current-setting resistors shouldplane. connect directly advertised , the actual output is connect to the power-ground The ISET = LLOUT = (3) 有助于IC散热。DC、SYS、BAT及USB至功率地的输入电 OUT __MIN MIN__TTOFF OFF K ×× ripple obtained by choosing an appropriate K IISDLIM and IDC current-setting resistors should connect directly SDLIMfactor K, and 容应尽量靠近IC放置。尽可能采用短而宽的布线作为大电 ______________________________________________________________________________________ 23 ______________________________________________________________________________________ 23 流引线，例如DC、SYS和BAT的连线。关于PCB布局实例， 其中，t where ttOFF is the the minimum minimum off-time obtained obtained from from (1). (1). OFF where is off-time OFF是由式(1)得到的最小关断时间。 ______________________________________________________________________________________ 23 请参考MAX8903A评估板的数据资料。 (4) LLOUT (4) == OUT __MIN MIN__ ttON ON VSYS ( VVDC DC((MAX MAX)) −− V SYS((MIN MIN))) ×× ttON ON K ×× IISDLIM K SDLIM where VVDC(MAX) is maximum maximum input inputSYS(MIN) voltage, is where is voltage, VVSYS(MIN) DC(MAX) SYS(MIN) is 为最大输入电压，V 为充电器输出 其中，V DC(MAX) is the the ononthe minimum minimum charger charger output voltage, voltage, and and ttON the output ON is 电压最小值，t ON为输入电压较大时的导通时间，可由下 time at at high high input input voltage, voltage, as as given given by by the the following following time 式计算得出： equation: equation: (5) (5) VVSYS 11 SYS((MIN MIN)) 11 ,, ttON ×× ON == ttONMIN ONMIN ifif ONMIN ≤≤ ttONMIN ttO O VVDC DC((MAX MAX)) ffSW SW otherwise, otherwise, O O ttON ON == VVSYS SYS((MIN MIN)) VVDC DC((MAX MAX)) ×× (( )) ,, 11 ffSW SW tion satura current DC DC rating rating of of the the inductor inductor (I(ISAT The satura tion current The SAT)) must be be greater greater than than the the DC DC step-down step-down output output current current must limit (I(ISDLIM plus one-half one-half the the maximum maximum ripple ripple current, current, limit SDLIM)) plus as given given by by equation equation (6). (6). as ILRIPPLE IL RIPPLE__MAX MAX 23 , , , MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器，用于 USB和适配器供电系统 to GND to avoid current errors. Connect GND to the exposed pad directly under the IC. Use multiple tightly spaced vias to the ground plane under the exposed pad to help cool the IC. Position input capacitors from DC, SYS, BAT, and USB to the power-ground plane as close as possible to the IC. Keep high current traces such as those to DC, SYS, and BAT as short and wide as possible. Refer to the MAX8903A Evaluation Kit for a suitable 2A单节Li+电池DC-DC充电器， 用于USB和适配器供电系统 表5. 推荐电感示例 DC INPUT VOLTAGE RANGE 5V ±10% 5V ±10% 5V ±10% 5V ±10% 9V ±10% 9V ±10% 24 24 DC STEP-DOWN OUTPUT CURRENT LIMIT (ISDMAX) PART NUMBER, SWITCHING FREQUENCY* RECOMMENDED INDUCTOR MAX8903H/J/N/Y, 4MHz 1.0µH, IFSC1008ABER1R0M01, Vishay 2.5mm x 2mm x 1.2mm, 43mΩ (max), 2.6A or 1.0µH, LQH32PN1R0-NN0, Murata, 3.2mm x 2.5mm x 1.55mm, 54mΩ (max), 2.3A 1A MAX8903H/J/N/Y, 4MHz 1.5µH inductor, MDT2520-CN1R5M, TOKO 2.5mm x 2.0mm x 1.2mm, 123.5mΩ (max), 1.25A or 1.5uH Inductor, IFSC1008ABER1R5M01, Vishay 2.5mm x 2mm x 1.2mm, 72mΩ (max), 2.2A 2A MAX8903A/B/C/D/E, 4MHz 2.2µH inductor, DFE322512C-2R2N, TOKO 3.2mm x 2.5mm x 1.2mm, 91mΩ (max), 2.4A or 2.2µH inductor, IFSC1515AHER2R2M01, Vishay 3.8mm x 3.8mm x 1.8mm, 45mΩ (max), 3A 1A MAX8903A/B/C/D/E, 4MHz 2.2µH inductor, IFSC1008ABER2R2M01, Vishay 2.5mm x 2mm x 1.2mm, 90mΩ (max), 2.15A or 2.2µH Inductor, LQH32PN2R2-NN0, Murata 3.2mm x 2.5mm x 1.55mm, 91mΩ (max), 1.55A MAX8903H/J/N/Y, 4MHz 1.5uH inductor, IFSC1008ABER1R5M01, Vishay 2.5mm x 2mm x 1.2mm, 72mW (max), 2.2A or 1.5µH Inductor, VLS4012ET-1R5N, TDK 4mm x 4mm x 1.2mm, 72mW (max), 2.1A MAX8903H/J/N/Y, 4MHz 2.2µH inductor, IFSC1008ABER2R2M01, Vishay 2.5mm x 2mm x 1.2mm, 90mΩ (max), 2.15A or 2.2µH inductor, LQH3NPN2R2NJ0, Murata 3mm x 3mm x 1.1mm, 83mΩ (max), 1.15A 2A 2A 1A ______________________________________________________________________________________ 5V ±10% 9V ±10% 9V ±10% 1A 2A 1A 4MHz or 2.2µH Inductor, LQH32PN2R2-NN0, Murata 3.2mm x 2.5mm x 1.55mm, 91mΩ (max), 1.55A MAX8903H/J/N/Y, 4MHz 1.5uH inductor, IFSC1008ABER1R5M01, Vishay 2.5mm x 2mm x 1.2mm, 72mW (max), 2.2A or 1.5µH Inductor, VLS4012ET-1R5N, TDK 4mm x 4mm x 1.2mm, 72mW (max), 2.1A MAX8903H/J/N/Y, 4MHz 2.2µH inductor, IFSC1008ABER2R2M01, Vishay 2A单节Li+电池DC-DC充电器， 2.5mm x 2mm x 1.2mm, 90mΩ (max), 2.15A or 2.2µH inductor, LQH3NPN2R2NJ0, Murata 用于USB和适配器供电系统 3mm x 3mm x 1.1mm, 83mΩ (max), 1.15A DC INPUT VOLTAGE RANGE 9V ±10% 9V ±10% 9V ±10% 9V ±10% 12V ±10% 12V ±10% DC STEP-DOWN OUTPUT CURRENT LIMIT (ISDMAX ) PART NUMBER, SWITCHING FREQUENCY* 2A MAX8903A/B/C/D/E, 4MHz 2.2µH inductor, DFE322512C-2R2N, TOKO 3.2mm x 2.5mm x 1.2mm, 91mΩ (max), 2.4A or 2.2µH Inductor, IFSC1515AHER2R2M01, Vishay 3.8mm x 3.8mm x 1.8mm, 45mΩ (max), 3A 1A MAX8903A/B/C/D/E, 4MHz 2.2µH Inductor, IFSC1008ABER2R2M01, Vishay 2.5mm x 2mm x 1.2mm, 90mΩ (max), 2.15A or 2.2µH Inductor, LQH3NPN2R2NJ0, Murata 3mm x 3mm x 1.1mm, 83mΩ (max), 1.15A 2A 1A 2A 1A MAX8903A-E/G/H/J/N/Y 表5. 推荐电感示例(续) RECOMMENDED INDUCTOR MAX8903G, 1MHz 4.3uH Inductor, DEM4518C (1235AS-H-4R3M), TOKO 4.7mm x 4.5mm x 1.8mm, 84mΩ (max), 2.0A or 4.7µH Inductor, IFSC1515AHER4R7M01, Vishay 3.8mm x 3.8mm x 1.8mm, 90mΩ (max), 2.0A MAX8903G, 1MHz 4.7µH inductor, DEM2818C (1227AS-H-4R7M), TOKO 3.2mm x 2.8mm x 1.8mm, 92mΩ (max), 1.1A or 4.7µH inductor, IFSC1008ABER4R7M01, Vishay 2.5mm x 2mm x 1.2mm, 212mΩ (max), 1.2A MAX8903G, 1MHz 4.3µH inductor, DEM4518C (1235AS-H-4R3M), TOKO 4.7mm x 4.5mm x 1.8mm, 84mΩ (max), 2.0A or 4.7µH inductor, IFSC1515AHER4R7M01, Vishay 3.8mm x 3.8mm x 1.8mm, 90mΩ (max), 2.0A MAX8903G, 1MHz 6.8µH, IFSC1515AHER6R8M01, Vishay 3.8mm x 3.8mm x 1.8mm, 115mΩ (max), 1.5A or 6.8µH, LQH44PN6R8MP0, Murata 4mm x 4mm x 1.65mm, 144mΩ (max), 1.34A *关于器件型号的更多信息，请参见选型指南。 25 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 Selector Guide The MAX8903_ is available in several options选型指南 designated by the first letter following the root part number. The MAX8903_提供不同版本的器件，采用固定器件型号后的第 basic architecture and functionality of the 一个字母进行区分。MAX8903A-MAX8903E/MAX8903G/ MAX8903A–MAX8903E/MAX8903G/MAX8903Y are the same. Their differences lie in certain electrical and MAX8903H/MAX8903J/MAX8903N/MAX8903Y的基本架 operational parameters. Table 6 outlines these differ构和功能是相同的，不同之处在于具体的电气参数和工作 ences. 参数。表6列出了各器件版本之间的不同之处。 表6. 选型指南 PARAMETER MAX8903A MAX8903B MAX8903C MAX8903D MAX8903E MAX8903G MAX8903H MAX8903J MAX8903N MAX8903Y Minimum SYS Regulation Voltage (VSYSMIN) 3.0V 3.0V 3.4V 3.4V 3.0V 3.0V 3.4V 3.4V 3.4V 3.0V SYS Regulation Voltage (VSYSREG) 4.4V 4.325V 4.4V 4.4V 4.325V 4.325V 4.4V 4.5V 4.4V 4.4V Minimum Allowable Inductor 2.2µH 2.2µH 2.2µH 2.2µH 2.2µH 2.2µH 1µH 1µH 1µH 1µH Switching Frequency 4MHz 4MHz 4MHz 4MHz 4MHz 1MHz 4MHz 4MHz 4MHz 4MHz SYS Load Regulation 40mV/A 25mV/A 40mV/A 40mV/A 25mV/A 25mV/A 40mV/A 25mV/A 25mV/A 25mV/A Minimum SYS Output Capacitor (CSYS) 10µF 22µF 10µF 10µF 22µF 22µF 10µF 10µF 22µF 22µF BAT Regulation Voltage (VBATREG) (Note 5) 4.2V 4.2V 4.2V 4.1V 4.1V 4.2V 4.2V 4.35V 4.15V 4.15V BAT Prequal Threshold (VBATPQ) (Note 5) 3V 2.5V 3V 3V 2.5V 2.5V 3V 3V 3V 3V Top-Off Timer (Note 6) 15s (fixed) 132min 15s (fixed) 15s (fixed) 132min 132min VL Output Current Rating 1mA 10mA 1mA 1mA 10mA 10mA 1mA 1mA 1mA 1mA Power-Enable On Battery Detection (Note 7) No Yes No No Yes Yes No No No No Comments — — — — — — (Note 8) — — — 15s (fixed) 15s (fixed) 15s (fixed) 15s (fixed) Note 5: Typical values. See the电气特性 Electrical Characteristics table for min/max values. 注5：典型值，最小/最大值参见 表。 注6：该变化也会更改预均衡和快充定时器的时间设置。 Note 6: Note that this also changes the timing for the prequal and fast-charge timers. 注7：详细信息请参见 电池检测的供电使能控制 部分。section for details. Note 7: See the Power Enable on Battery Detection 注8：MAX8903H是MAX8903C的新版本，推荐用于新设计。 26 26 ______________________________________________________________________________________ 2A单节Li+电池DC-DC充电器， 2A单节Li+电池DC-DC充电器，用于 USB和适配器供电系统 用于USB和适配器供电系统 BAT BAT UOK FLT USB THM USUS TOP VIEW 21 20 19 18 17 16 15 CHG 22 14 CEN SYS 23 13 ISET SYS 24 12 GND 11 IDC 10 CT MAX8903_ CS 25 CS 26 LX 27 EP 5 6 7 IUSB DC 4 BST 3 DCM 2 DC 1 PG + PG LX 28 9 VL 8 DOK PROCESS: PROCESS: BiCMOS BiCMOS 芯片信息 Chip Information TQFN ______________________________________________________________________________________ 27 27 MAX8903A-E/G/H/J/N/Y 引脚配置 Pin Configuration MAX8903A-E/G/H/J/N/Y 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 封装信息 Package Information 如需最近的封装外形信息和焊盘布局(占位面积)，请查询china.maxim-ic.com/packages。请注意，封装编码中的 “+” “#”或 “-” For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that、 a "+", "#", or 仅表示RoHS状态。封装图中可能包含不同的尾缀字符，但封装图只与封装有关，与RoHS状态无关。 "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing per封装类型 PACKAGE TYPE 28 TQFN-EP 28 TQFN-EP 28 28 封装编码 PACKAGE CODE T2844-1 T2844-1 外形编号 OUTLINE NO. 21-0139 21-0139 LAND 焊盘布局编号 PATTERN NO. 90-0035 90-0035 ______________________________________________________________________________________ 2A单节Li+电池DC-DC充电器，用于 2A单节Li+电池DC-DC充电器， USB和适配器供电系统 用于USB和适配器供电系统 For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a "+", "#", or 如需最近的封装外形信息和焊盘布局(占位面积)，请查询china.maxim-ic.com/packages。请注意，封装编码中的“+”、“#”或“-” "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing per仅表示RoHS状态。封装图中可能包含不同的尾缀字符，但封装图只与封装有关，与RoHS状态无关。 ______________________________________________________________________________________ 29 29 MAX8903A-E/G/H/J/N/Y MAX8903A-E/G/H/J/N/Y Package Information (continued) 封装信息(续) 2A单节Li+电池DC-DC充电器， 用于USB和适配器供电系统 MAX8903A-E/G/H/J/N/Y 修订历史 修订号 修订日期 0 12/08 最初版本。 说明 修改页 1 8/09 在数据资料中增加了MAX8903C/MAX8903D。 2 11/09 做了多处修正。 3 10/10 增加了MAX8903B、MAX8903E、MAX8903G和MAX8903Y。 1–29 4 5/11 增加了MAX8903H和MAX8903J，更新了元件值。 1–29 5 9/11 增加了MAX8903N，删除了MAX8903J的未来产品标识。 1–29 — 1–20 1–7, 9, 11–21 Maxim北京办事处 北京8328信箱 邮政编码100083 免费电话：800 810 0310 电话：010-6211 5199 传真：010-6211 5299 Maxim不对Maxim产品以外的任何电路使用负责，也不提供其专利许可。Maxim保留在任何时间、没有任何通报的前提下修改产品资料和规格的权利。电气 特性表中列出的参数值(最小值和最大值)均经过设计验证，数据资料其它章节引用的参数值供设计人员参考。 30 © Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 2011 Maxim Integrated Products Maxim是Maxim Integrated Products，Inc.的注册商标。 MAX8903A, MAX8903B, MAX8903C, MAX8903D, MAX8903E, MAX8903G, MAX8903H, MAX8903J, MAX8903N, MAX8903Y 2A 1节Li+电池DC-DC充电器，用于USB和适配器供电系统 - 概述 Login Register 产品 方案 设计 销售联络 技术支持 公司简介 简体中文 (cn) 简体中文 (cn) 我的Maxim Maxim > 产品 > 电源和电池管理 > MAX8903A, MAX8903B, MAX8903C, ... MAX8903A, MAX8903B, MAX8903C, MAX8903D, MAX8903E, MAX8903G, MAX8903H, MAX8903J, MAX8903N, MAX8903Y 2A 1节Li+电池DC-DC充电器，用于USB和适配器供电系统 工作在4MHz开关频率 概述 技术文档 定购信息 相关产品 用户说明 (0) 所有内容 状况 状况：生产中。 数据资料 英文 概述 MAX8903A–MAX8903E/MAX8903G/MAX8903H/MAX8903J/MAX8903Y是一款集成的单节Li+电池充电器 和Smart Power Selector™ (智能电源选择器)，工作于双电源输入(交流适配器和USB)。开关模式充电器工作在高 开关频率，可省去散热器并允许使用小尺寸外部元件。该器件可采用独立的USB电源或交流适配器供电，也可以 用一个输入端接收两路电源输入。芯片集成了所有充电功能和用于切换电池、外部电源、负载的功率开关。无需外 部MOSFET、反向保护二极管和检流电阻。 MAX8903_具有经过优化的智能功率控制功能，可充分利用有限的USB或适配器电源的供电能力。电池充电电流 和SYS输出限流均可独立设置。在保证系统供电的前提下为电池充电。充电电流和SYS输出限流可设置在最 高2A，USB输入限流可设置在100mA或500mA。输入选择电路可自动地将系统供电电源从电池切换至外部电源。 器件工作在4.15V至16V直流输入电压范围，输入端具有高达20V的保护；USB输入范围为4.1V至6.3V，输入端具 有最高8V的保护。 未接输入电源时，MAX8903_内部电路可以阻止电流从电池、系统向直流电源、USB输入倒灌。其它功能还包括 预充检测及定时器、快充定时器、过压保护、充电状态指示和故障指示输出、电源就绪监视器以及电池热敏电阻检 测。此外，片内热管理电路可以根据需要降低电池充电速率或交流适配器的充电电流，以防止充电器过 热。MAX8903_采用4mm x 4mm、28引脚薄型QFN封装。 不同版本的MAX8903_提高了设计灵活性，便于选择不同的系统电源电压、电池预检验门限和电池满充电 压。MAX8903B/MAX8903E/MAX8903G的电池检测功能还包含供电使能控制，详细信息请参考完整数据资料中 的选型指南部分。 http://china.maxim-ic.com/datasheet/index.mvp/id/6019[2012-07-09 8:43:44] 中文 下载 Rev. 5 (PDF, 1.3MB) E-Mail 下载 Rev. 5 (PDF, 3MB) E-Mail MAX8903A, MAX8903B, MAX8903C, MAX8903D, MAX8903E, MAX8903G, MAX8903H, MAX8903J, MAX8903N, MAX8903Y 2A 1节Li+电池DC-DC充电器，用于USB和适配器供电系统 - 概述 MAX8903支持低温、快速充电 现备有评估板：MAX8903AEVKIT 关键特性 应用/使用 高效DC-DC转换器，无需散热器 4MHz开关频率，允许使用小尺寸外部元件 立即开启—可在无电池或低电池电压下工作 两路限流输入—交流适配器或USB 适配器/USB/电池供电自动切换，支持瞬变负载 50mΩ系统至电池开关导通电阻 支持USB规范 热敏电阻检测 集成检流电阻 无需外部MOSFET或二极管 4.1V至16V输入工作电压范围 移动互联网设备 PDA、掌上电脑和无线手持装置 个人导航设备 便携式多媒体播放器 智能蜂窝电话 超便携移动PC 关键特性: Battery Chargers Part Number Cell Chemistry Lithium Ion Cells Protected V IN (V) Charging V IN (V) max max Charge Rate Set by Max. I CHG (A) Charge Termination Charge Regulation EV Kit Oper. Temp. (°C) ≥ MAX8903A MAX8903B MAX8903C Li-Ion Li-Polymer 1 20 16 Preset Resistor 2 Min. Charge Current Switchmode MAX8903D 查看所有Battery Chargers (70) Pricing Notes: This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor. 图表 http://china.maxim-ic.com/datasheet/index.mvp/id/6019[2012-07-09 8:43:44] Package/Pins Yes -40 to +85 Smallest Available Pckg. (mm 2 ) Budgetary Price max w/pins See Notes TQFN/28 $2.74 @1k TQFN/28 $2.74 @1k TQFN/28 TQFN/28 16.8 $2.74 @1k $2.74 @1k MAX8903A, MAX8903B, MAX8903C, MAX8903D, MAX8903E, MAX8903G, MAX8903H, MAX8903J, MAX8903N, MAX8903Y 2A 1节Li+电池DC-DC充电器，用于USB和适配器供电系统 - 概述 典型工作电路 更多信息 新品发布 [ 2009-06-29 ] 没有找到你需要的产品吗？ 应用工程师帮助选型，下个工作日回复 参数搜索 应用帮助 信息索引 概述 技术文档 定购信息 相关产品 概述 关键特性 应用/使用 关键指标 图表 注释、注解 数据资料 技术文档 评估板 可靠性报告 软件/模型 价格与供货 样品 在线订购 封装信息 无铅信息 类似功能器件 类似应用器件 评估板 类似型号器件 配合该器件使用的产品 参考文献： 19- 4410 Rev. 5; 2011- 10- 04 本页最后一次更新: 2011- 10- 04 联络我们：信息反馈、提出问题 | 隐私权政策 | 法律声明 | Distributor Portal © 2012 Maxim Integrated Products版权所有 http://china.maxim-ic.com/datasheet/index.mvp/id/6019[2012-07-09 8:43:44] 19-4410; Rev 5; 9/11 KIT ATION EVALU E L B AVAILA 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power The MAX8903A–MAX8903E/MAX8903G/MAX8903H/ MAX8903J/MAX8903N/MAX8903Y are integrated 1-cell Li+ chargers and Smart Power Selectors™ with dual (AC adapter and USB) power inputs. The switch mode charger uses a high switching frequency to eliminate heat and allow tiny external components. It can operate with either separate inputs for USB and AC adapter power, or from a single input that accepts both. All power switches for charging and switching the load between battery and external power are included onchip. No external MOSFETs, blocking diodes, or current-sense resistors are required. The MAX8903_ features optimized smart power control to make the best use of limited USB or adapter power. Battery charge current and SYS output current limit are independently set. Power not used by the system charges the battery. Charge current and SYS output current limit can be set up to 2A while USB input current can be set to 100mA or 500mA. Automatic input selection switches the system from battery to external power. The DC input operates from 4.15V to 16V with up to 20V protection, while the USB input has a range of 4.1V to 6.3V with up to 8V protection. The MAX8903_ internally blocks current from the battery and system back to the DC and USB inputs when no input supply is present. Other features include prequal charging and timer, fast charge timer, overvoltage protection, charge status and fault outputs, power-OK monitors, and a battery thermistor monitor. In addition, on-chip thermal limiting reduces battery charge rate and AC adapter current to prevent charger overheating. The MAX8903_ is available in a 4mm x 4mm, 28-pin thin QFN package. The various versions of the MAX8903_ allow for design flexibility to choose key parameters such as system regulation voltage, battery prequalification threshold, and battery regulation voltage. The MAX8903B/ MAX8903E/MAX8903G also includes power-enable on battery detection. See the Selector Guide section for complete details. Features o o o o o o o o Efficient DC-DC Converter Eliminates Heat 4MHz Switching for Tiny External Components Instant On—Works with No/Low Battery Dual Current-Limiting Inputs—AC Adapter or USB Automatic Adapter/USB/Battery Switchover to Support Load Transients 50mΩ System-to-Battery Switch Supports USB Spec Thermistor Monitor Integrated Current-Sense Resistor No External MOSFETs or Diodes 4.1V to 16V Input Operating Voltage Range Ordering Information PART TEMP RANGE PIN-PACKAGE MAX8903AETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903BETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903CETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903DETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903EETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903GETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903HETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903JETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903NETI+T -40°C to +85°C 28 Thin QFN-EP* MAX8903YETI+T -40°C to +85°C 28 Thin QFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. T = Tape and reel. Typical Operating Circuit AC ADAPTER OR USB LX SYS CHARGE CURRENT Applications PDAs, Palmtops, and Wireless Handhelds Personal Navigation Devices Smart Cell Phones Portable Multimedia Players Mobile Internet Devices Ultra Mobile PCs Selector Guide appears at end of data sheet. Smart Power Selector is a trademark of Maxim Integrated Products, Inc. CS DC PWM STEP-DOWN USB LOAD CURRENT CHARGE AND SYS LOAD SWITCH BAT USB MAX8903_ SYSTEM LOAD BATTERY GND Pin Configuration appears at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX8903A–E/G/H/J/N/Y General Description MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power ABSOLUTE MAXIMUM RATINGS DC, LX to GND .......................................................-0.3V to +20V DCM to GND ..............................................-0.3V to (VDC + 0.3V) DC to SYS .................................................................-6V to +20V BST to GND ...........................................................-0.3V to +26V BST TO LX ................................................................-0.3V to +6V USB to GND .............................................................-0.3V to +9V USB to SYS..................................................................-6V to +9V VL to GND ................................................................-0.3V to +6V THM, IDC, ISET, CT to GND........................-0.3V to (VVL + 0.3V) DOK, FLT, CEN, UOK, CHG, USUS, BAT, SYS, IUSB, CS to GND ................................-0.3V to +6V SYS to BAT ...............................................................-0.3V to +6V PG, EP (exposed pad) to GND .............................-0.3V to +0.3V DC Continuous Current (total in two pins)......................2.4ARMS USB Continuous Current.......................................................1.6A LX Continuous Current (total in two pins).......................2.4ARMS CS Continuous Current (total in two pins) ......................2.4ARMS SYS Continuous Current (total in two pins) .......................3ARMS BAT Continuous Current (total in two pins) .......................3ARMS VL Short Circuit to GND .............................................Continuous Continuous Power Dissipation (TA = +70°C) 28-Pin Thin QFN-EP Multilayer (derate 28.6mW/°C above +70°C) ..........2286mW 28-Pin Thin QFN-EP Single-Layer (derate 20.8mW/°C above +70°C)...1666.7mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature Range ............................-40°C to +150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VDC = VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 16 V 3.9 4.0 4.0 4.3 4.1 4.4 V 16.5 17 17.5 V Charger enabled, no switching, VSYS = 5V 2.3 4 Charger enabled, f = 3MHz, VDC = 5V 15 Charger enabled, VCEN = 0V, 100mA USB mode (Note 2) 1 2 Charger enabled, VCEN = 5V, 100mA USB mode (Note 2) VDCM = 0V, VUSUS = 5V 1 0.10 2 0.25 DC INPUT DC Operating Range 4.15 No valid USB input Valid USB input DC Undervoltage Threshold When VDOK goes low, VDC rising, 500mV typical hysteresis DC Overvoltage Threshold When VDOK goes high, VDC rising, 500mV typical hysteresis DC Supply Current DC High-Side Resistance Ω 0.15 DC Low-Side Resistance DC-to-BAT Dropout Resistance Assumes a 40mΩ inductor resistance (RL) DC-to-BAT Dropout Voltage When SYS regulation and charging stops, VDC falling, 200mV hysteresis 0 mA 0.15 Ω 0.31 Ω 15 30 mV Minimum Off Time (tOFFMIN) 100 ns Minimum On Time (tONMIN) ns VDC = 8V, VBAT = 4V 70 4 MAX8903A/B/C/D/E/H/J/Y Switching Frequency (fSW) MAX8903G VDC = 5V, VBAT = 3V 3 VDC = 9V, VBAT = 4V 1 VDC = 9V, VBAT = 3V 1 DC Step-Down Output CurrentLimit Step Range DC Step-Down Output Current Limit (ISDLIM) 2 0.5 VDC = 6V, VSYS = 4V MHz 2 RIDC = 3kΩ 1900 2000 2100 RIDC = 6kΩ RIDC = 12kΩ 950 450 1000 500 1050 550 _______________________________________________________________________________________ A mA 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power (VDC = VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER DC Soft-Start Time DC Output Current 500mA USB Mode (Note 3) DC Output Current 100mA USB Mode (Note 2) SYS to DC Reverse Current Blocking CONDITIONS MIN TYP MAX UNITS No valid USB input 1 ms Valid USB input before soft-start 20 μs VDCM = 0V, VIUSB = 5V 450 475 500 mA VDCM = 0V, VIUSB = 0V 90 95 100 mA VSYS = 5.5V, VDC = 0V 0.01 μA USB INPUT USB Operating Range 4.1 6.3 USB Standoff Voltage USB Undervoltage Threshold USB Overvoltage Threshold USB Current Limit USB Supply Current When VUOK goes low, VUSB rising, 500mV hysteresis 3.95 4.0 V V When VUOK goes high, VUSB rising, 500mV hysteresis 6.8 6.9 7.0 90 95 100 VIUSB = 5V (500mA setting) 450 475 500 ISYS = IBAT = 0mA, VCEN = 0V 1.3 3 ISYS = IBAT = 0mA, VCEN = 5V 0.8 2 0.115 0.25 Minimum USB to BAT Headroom 0 USB to SYS Dropout Resistance USB Soft-Start Time V 4.05 VIUSB = 0V (100mA setting) VUSUS = 5V (USB suspend mode) V 8 mA mA 15 30 mV 0.2 0.35 Ω VUSB rising 1 ms VDC falling below DC UVLO to initiate USB soft-start 20 μs SYS OUTPUT Minimum SYS Regulation Voltage (VSYSMIN) ISYS = 1A, VBAT < VSYSMIN MAX8903A/B/E/G/Y 3.0 MAX8903C/D/H/J/N 3.4 MAX8903A/C/D/H/N/Y Regulation Voltage ISYS = 0A MAX8903B/E/G MAX8903J V 4.3 4.4 4.5 4.265 4.325 4.395 4.4 4.5 4.55 MAX8903A/C/D/H 40 MAX8903B/E/G/J/N/Y 25 V Load Regulation ISYS = 0 to 2A mV/A CS to SYS Resistance VDC = 6V, VDCM = 5V, VSYS = 4V, ICS = 1A 0.07 Ω SYS to CS Leakage VSYS = 5.5V, VDC = VCS = 0V 0.01 μA BAT to SYS Resistance VDC = VUSB = 0V, VBAT = 4.2V, ISYS = 1A 0.05 0.1 Ω BAT to SYS Reverse Regulation Voltage VUSB = 5V, VDC = 0V, VIUSB = 0V, ISYS = 200mA 50 75 100 mV SYS Undervoltage Threshold SYS falling, 200mV hysteresis (Note 4) 1.8 1.9 2.0 V _______________________________________________________________________________________ 3 MAX8903A–E/G/H/J/N/Y ELECTRICAL CHARACTERISTICS (continued) MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power ELECTRICAL CHARACTERISTICS (continued) (VDC = VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX 4.221 UNITS BATTERY CHARGER MAX8903A/B/C/G/H MAX8903D/E BAT Regulation Voltage (VBATREG) IBAT = 0mA MAX8903J MAX8903Y/N TA = +25°C 4.179 4.200 TA = -40°C to +85°C 4.158 4.200 4.242 TA = +25°C 4.079 4.100 4.121 TA = -40°C to +85°C 4.059 4.100 4.141 TA = +25°C 4.328 4.350 4.372 TA = -40°C to +85°C 4.307 4.350 4.394 TA = +25°C 4.129 4.150 4.171 TA = -40°C to +85°C 4.109 4.150 4.192 Charger Restart Threshold Change in VBAT from DONE to fast-charge BAT Prequal Threshold (VBATPQ) VBAT rising 180mV hystersis -150 -100 -60 MAX8903A/C/D/H/J/N/Y 2.9 3.0 3.1 MAX8903B/E/G 2.4 2.5 2.6 RISET = 600Ω 1800 2000 2200 Fast-Charge Current RISET = 1.2kΩ (MAX8903A/C/D) 900 1000 1100 RISET = 2.4kΩ 450 500 550 DONE Threshold (ITERM) Percentage of fast-charge, IBAT decreasing Prequal Charge Current Percentage of fast-charge current set at ISET RISET Resistor Range 10 mV V % 10 0.6 V mA % 2.4 kΩ ISET Output Voltage 1.5 V ISET Current Monitor Gain 1.25 mA/A BAT Leakage Current No DC or USB input With valid input power, VCEN = 5V 0.05 4 3 6 μA Charger Soft-Start Time 1.0 ms Charger Thermal Limit Temperature 100 °C 5 %/°C Charger Thermal Limit Gain Charge current = 0 at +120°C CHARGER TIMER Prequalification Time CCT = 0.15μF 33 min Fast-Charge Time CCT = 0.15μF 660 min Top-Off Timer (tTOP-OFF) MAX8903A/C/D/H/J/N/Y (fixed) 15 s MAX8903B/E/G, CCT = 0.15μF 132 min Timer Accuracy -15 +15 % Timer Extend Current Threshold Percentage of fast-charge current below which the timer clock operates at half-speed 40 50 60 % Timer Suspend Current Threshold Percentage of fast-charge current below which timer clock pauses 16 20 24 % 4 _______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power (VDC = VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS THERMISTOR MONITOR THM Threshold, Hot When charging is suspended, 1% hysteresis 0.27 x VVL 0.28 x VVL 0.29 x VVL V THM Threshold, Cold When charging is suspended, 1% hysteresis 0.73 x VVL 0.74 x VVL 0.75 x VVL V THM Threshold, Disabled THM function is disabled below this voltage 0.0254 x VVL 0.03 x VVL 0.036 x VVL V THM Threshold DC, USB Enable MAX8903B/MAX8903E/MAX8903G 0.83 x VVL 0.87 x VVL 0.91 x VVL V -0.100 ±0.001 +0.200 MAX8903A/C/D/H/J/N/Y THM = GND or VL; TA = +25°C THM = GND or VL; TA = +85°C THM Input Leakage MAX8903B/E/G THM = GND or VL; TA = -40°C to +85°C μA ±0.010 -0.200 ±0.001 +0.200 THERMAL SHUTDOWN, VL, AND LOGIC I/O: CHG, FLT, DOK, UOK, DCM, CEN, USUS, IUSB High level Logic-Input Thresholds (DCM, CEN, USUS, IUSB) Logic-Input Leakage Current (CEN, USUS, IUSB) 1.3 Low level 0.4 Hysteresis VINPUT = 0V to 5.5V (MAX8903A/C/D/H/J/N/Y) VINPUT = 0V to 5.5V (MAX8903B/E/G) 50 TA = +25°C -1.000 TA = +85°C TA = -40°C to +85°C ±0.001 μA ±0.001 +0.200 TA = +25°C 0.001 1 TA = +85°C 0.01 Logic-Input Leakage Current (DCM) VDCM = 0V to 16V VDC = 16V Logic Output Voltage, Low (CHG, FLT, DOK, UOK) Sinking 1mA 8 Sinking 10mA 80 Open-Drain Output Leakage VOUT = 5.5V Current, High (CHG, FLT, DOK, UOK) mV +1.000 ±0.010 -0.200 TA = +25°C 0.001 TA = +85°C 0.01 V 50 1 μA mV μA _______________________________________________________________________________________ 5 MAX8903A–E/G/H/J/N/Y ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (VDC = VUSB = 5V, VBAT = 4V, circuit of Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS VL Output Voltage MIN TYP MAX IVL = 0 to 1mA (MAX8903A/C/D/H/J/N/Y) 4.6 5.0 5.4 IVL = 0 to 10mA (MAX8903B/E/G) 4.6 5.0 5.4 UNITS V VDC = VUSB = 6V VL UVLO Threshold VVL falling; 200mV hysteresis 3.2 V Thermal Shutdown Temperature 160 °C Thermal Shutdown Hysteresis 15 °C Note 1: Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed by design. Note 2: For the 100mA USB mode using the DC input, the step-down regulator is turned off and its high-side switch operates as a linear regulator with a 100mA current limit. The linear regulator’s output is connected to LX and its output current flows through the inductor into CS and finally to SYS. Note 3: For the 500mA USB mode, the actual current drawn from USB is less than the output current due to the input/output current ratio of the DC-DC converter. Note 4: For short-circuit protection, SYS sources 25mA below VSYS = 400mV, and 50mA for VSYS between 400mV and 2V. Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) MAX8903A/B/C/D/E/H/J/N/Y BATTERY CHARGER EFFICIENCY vs. BATTERY VOLTAGE VDC = 8V 50 VDC = 12V 40 30 70 VDC = 9V 60 50 VDC = 12V 40 30 IBAT = 0.15A 20 IBAT = 1.5A IBATT = 0.15A 20 10 IBATT = 1.5A 1.5 2.0 2.5 3.0 3.5 4.0 BATTERY VOLTAGE (V) 4.5 5.0 MAX8903A toc02 4.0 3.5 VBAT = 3V 3.0 2.5 VBAT = 4V 2.0 1.5 1.0 RISET = 1.2kΩ VCEN = 0V 0.0 0 1.0 4.5 0.5 10 0 6 VDC = 6V 80 EFFICIENCY (%) 70 90 SWITCHING FREQUENCY (MHz) VDC = 5V 60 100 MAX8903A/B/C/D/E/H/J/N/Y SWITCHING FREQUENCY vs. VDC MAX8903A toc01a 90 80 MAX8903G BATTERY CHARGER EFFICIENCY vs. BATTERY VOLTAGE MAX8903A toc01 100 EFFICIENCY (%) MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power 1.0 1.5 2.0 2.5 3.0 3.5 4.0 BATTERY VOLTAGE (V) 4.5 5.0 4 6 8 10 12 DC VOLTAGE (V) _______________________________________________________________________________________ 14 16 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power MAX8903A/B/C/D/E/H/J/N/Y SYS EFFICIENCY vs. SYS OUTPUT CURRENT VBAT = 4V VBAT = 3V 0.4 VDC = 11V 50 VDC = 16V 40 30 VDC = 6V 20 RISET = 1.2kI VCEN = 0V 0.2 10 6 8 10 12 14 VDC = 12V 40 VDC = 9V 30 VDC = 6V 0 10 100 1000 10000 10 1 100 USB SUPPLY CURRENT vs. USB VOLTAGE USB SUPPLY CURRENT vs. USB VOLTAGE (SUSPEND) BATTERY LEAKAGE CURRENT vs. BATTERY VOLTAGE 0.6 CHARGER DISABLED 0.4 120 100 80 60 40 80 20 0.2 MAX8903A toc06 140 MAX8903A toc05 MAX8903A toc04 0.8 70 60 50 40 30 20 10 NO DC OR USB INPUT USB SUSPEND 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 0 7 1 2 3 4 5 BATTERY VOLTAGE (V) BATTERY LEAKAGE CURRENT vs. AMBIENT TEMPERATURE CHARGE CURRENT vs. BATTERY VOLTAGE—USB MODE CHARGE CURRENT vs. BATTERY VOLTAGE—DC MODE 500 60 50 40 30 20 350 300 VIUSB = VUSB 250 200 VIUSB = 0V 150 100 10 NO DC OR USB INPUT 0 -15 10 35 TEMPERATURE (°C) 60 85 1000 CHARGE CURRENT (mA) 400 CHARGE CURRENT (mA) 70 CHARGE ENABLED IBAT SET TO 1.5A MAX8903D VBAT RISING 450 1200 MAX8903A toc08 80 800 6 MAX8903A toc09 USB VOLTAGE (V) MAX8903A toc07 BATTERY LEAKAGE CURRENT (nA) 0 0 USB VOLTAGE (V) 90 -40 10,000 SYS OUTPUT CURRENT (mA) 1.0 0 1000 SYS OUTPUT CURRENT (mA) CHARGER ENABLED 1.2 VDC = 16V 50 DC VOLTAGE (V) 1.6 1.4 60 10 VDC = 4.5V 1 16 USB QUIESCENT CURRENT (μA) 4 70 20 0 0 USB SUPPLY CURRENT (mA) 60 80 BATTERY LEAKAGE CURRENT (nA) 0.6 70 VCEN = 1 90 SYS EFFICIENCY (%) 1.0 0.8 80 SYS EFFICIENCY (%) 1.2 VCEN = 1V VSYS = 4.4V 90 100 MAX8903A toc03 1.4 SWITCHING FREQUENCY (MHz) 100 MAX8903A toc02a 1.6 MAX8903G SYS EFFICIENCY vs. SYS OUTPUT CURRENT MAX8903A toc03a MAX8903G SWITCHING FREQUENCY vs. VDC CHARGER ENABLED IBAT SET TO 1A IDC SET TO 2A MAX8903A/C/H VBAT RISING 600 400 200 50 0 0 1.5 2.0 2.5 3.0 3.5 BATTERY VOLTAGE (V) 4.0 4.5 1.5 2.0 2.5 3.0 3.5 4.0 4.5 BATTERY VOLTAGE (V) _______________________________________________________________________________________ 7 MAX8903A–E/G/H/J/N/Y Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) NORMALIZED BATTERY REGULATION VOLTAGE vs. AMBIENT TEMPERATURE 1.005 1.000 0.995 0.990 0.985 -40 -15 10 35 60 100.3 100.2 100.1 100.0 99.9 4.0 2.5 2.0 1.5 1.0 -40 -15 10 35 60 VUSB RISING 0.5 22ppm/°C 99.5 VUSB FALLING 3.0 RSYS = 1MΩ 0 0 85 1 2 3 4 5 6 7 TEMPERATURE (°C) USB VOLTAGE (V) MAX8903A/C/D/H/N/Y SYS VOLTAGE vs. DC VOLTAGE SYS VOLTAGE vs. SYS OUTPUT CURRENT, DC INPUT SYS VOLTAGE vs. SYS OUTPUT CURRENT, USB INPUT 2.0 VDC FALLING 1.5 VCEN = 5V VBAT = 0V VUSB = 0V 0.5 2 4 6 8 10 12 14 16 4.3 MAX8903A/C/D/H, MAX8903N/Y, VDC = 5.75V VDC = 5.75V 4.2 MAX8903B/E/G, VDC = 5.75V 4.1 0 0.5 1.0 1.5 VL WITH NO LOAD AND DCDC OFF (VUSUS = 5V) VL AND DCDC WITH FULL LOAD (VUSUS = 0V) 2 1 VBAT = 3.6V VUSB = 0V 0 4 6 8 10 12 14 16 18 20 DC VOLTAGE (V) VBAT (V) VL VOLTAGE (V) 5 2 MAX8903_, VUSB = 0V 3.8 2.0 0 100 200 300 400 SYS OUTPUT CURRENT (mA) CHARGE PROFILE—1400mAh BATTERY ADAPTER INPUT—1A CHARGE MAX8903A toc16 6 0 MAX8903B/E/G, VUSB = 5V 4.1 SYS OUTPUT CURRENT (A) VL VOLTAGE vs. DC VOLTAGE 3 MAX8903A/C/D/H, MAX8903N/Y, VUSB = 5V VUSB = 5V 4.2 3.9 MAX8903_, VDC = 0V 3.8 DC VOLTAGE (V) 4 4.3 4.0 3.9 18 MAX8903J, VUSB = 5V 4.4 4.0 1.0 VDC = 0V, VBATT = 4V 4.5 4.4 MAX8903A toc15 4.6 MAX8903A toc17 6.0 5.5 5.0 4.5 4.0 3.5 3.0 IDC SET TO 1A IBAT SET TO 2A VBAT 1.2 1.0 0.8 0.6 2.5 2.0 1.5 1.0 0.5 0 IBAT 0.4 0.2 MAX8903A/B/C/G/H 0 20 40 60 80 100 TIME (min) _______________________________________________________________________________________ 0.0 120 140 IBAT (A) 2.5 MAX8903J, VDC = 5.75V SYS VOLTAGE (V) VDC RISING 3.0 4.5 SYS VOLTAGE (V) 3.5 VUSB = 0V MAX8903A toc14 4.6 MAX8903A toc13 4.0 0 3.5 99.7 99.6 VCEN = 5V VBAT = 0V VDC = 0V 4.5 99.8 85 4.5 8 5.0 MAX8903A toc12 100.4 TEMPERATURE (°C) 5.0 0 100.5 SYS VOLTAGE (V) 1.010 MAX8903A/C/D/H/N/Y SYS VOLTAGE vs. USB VOLTAGE MAX8903A toc11 VUSB = 5V, VBAT = 4V NORMALIZED BATTERY REGULATION VOLTAGE (%) NORMALIZED CHARGE CURRENT 1.015 MAX8903A toc10 NORMALIZED CHARGE CURRENT vs. AMBIENT TEMPERATURE SYS VOLTAGE (V) MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power 500 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power MAX8903A/B/C/G/H CHARGE PROFILE—1400mAh BATTERY USB INPUT—500mA CHARGE MAX8903A toc18 5.0 0.45 4.0 0.40 0.25 IBAT 2.0 0.20 1.5 0.15 MAX8903A/MAX8903B/MAX8903C IUSB SET TO 500mA IBAT SET TO 2A 0.5 0 0 IBAT (A) 0.30 2.5 1.0 20mV/div AC-COUPLED VOUT 0.35 VBAT 3.0 MAX8903A toc19 0.50 4.5 3.5 VBAT (V) MAX8903A/B/C/D/E/H/J/N/Y DC SWITCHING WAVEFORMS—LIGHT LOAD 0.10 5V/div VLX 0V ILX 0.05 RSYS = 44Ω 0 20 40 60 80 100 120 140 160 180 200 500mA/div 0A 200ns/div TIME (min) MAX8903A/B/C/D/E/H/J/N/Y DC SWITCHING WAVEFORMS—HEAVY LOAD MAX8903G DC SWITCHING WAVEFORMS—LIGHT LOAD MAX8903A toc20 MAX8903A toc19a 50mV/div AC-COUPLED VSYS VLX VDC = 9V, L = 2.2μH CSYS = 22μF, RSYS = 44I 10V/div 20mV/div AC-COUPLED VOUT 5V/div 0V VLX 0V 1A/div ILX 0A ILX 500mA/div RSYS = 5Ω 1μs/div 200ns/div MAX8903G DC SWITCHING WAVEFORMS—HEAVY LOAD DC CONNECT WITH USB CONNECTED (RSYS = 25Ω) MAX8903A toc21 MAX8903A toc20a VSYS VDC = 9V, L = 2.2μH CSYS = 22μF, RSYS = 5I CEN = 1 50mV/div AC-COUPLED VSYS 0V IUSB 2V/div 347mA 475mA 500mA/div 500mA/div -IBAT = CHARGING IBAT ILX 3.6V IDC 10V/div VLX 0A 0A 500mA/div -335mA 1A/div 0A 1μs/div 200μs/div _______________________________________________________________________________________ 9 MAX8903A–E/G/H/J/N/Y Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) DC CONNECT WITH NO USB (RSYS = 25Ω) DC DISCONNECT WITH NO USB (RSYS = 25Ω) MAX8903A toc22 3.84V 3.6V VSYS 3.6V VBAT IBAT 2V/div 3.44V 5V/div CDC CHARGING IDC MAX8903A toc23 CSYS CHARGING 850mA 0A 1A/div 3.68V VSYS 5V/div -IBAT = CHARGING IBAT 144mA BATTERY CHARGER SOFT-START -1A 144mA -1A 1A/div 40μs/div MAX8903B/E SYS LOAD TRANSIENT MAX8903A toc24a MAX8903A toc24b 4.400V MAX8903A VDC = 10.5V L = 2.2μH CSYS = 10μF RIDC = 3kI (2A) DCM = HIGH CEN = 1 20mV/div AC-COUPLED 4.360V 4.325V VSYS MAX8903B VDC = 10.5V L = 2.2μH CSYS = 22μF RIDC = 3kI (2A) DCM = HIGH CEN = 1 4.305V 1A 20mV/div 1A 500mA/div 0A 0A ISYS 500mA/div 0A 0A 100μs/div 100μs/div MAX8903G SYS LOAD TRANSIENT USB CONNECT WITH NO DC (RSYS = 25Ω) MAX8903A toc25 MAX8903A toc24c VSYS 4.325V VSYS 4.305V 1A ISYS 50mV/div VDC = 9V L = 2.2μH CSYS = 22μF RIDC = 3kI (2A) DCM = 1 CEN = 1 0A 100μs/div 10 1A/div -IBAT = CHARGING MAX8903A/C/D/H SYS LOAD TRANSIENT ISYS 1A/div 0A 850mA 400μs/div VSYS 2V/div 3.6V VBAT IDC 3.6V 3.6V 3.75V 3.5V 5V 5V/div VUSB CUSB CHARGING 2V/div 475mA 500mA/div IUSB 500mA/div 0A IBAT 144mA BATTERY CHARGER SOFT-START 500mA/div -330mA 400μs/div ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power USB DISCONNECT WITH NO DC (RSYS = 25Ω) USB SUSPEND MAX8903A toc26 VSYS 3.6V VUSB 2V/div 5V/div 5V 475mA IUSB 500mA/div VSYS IUSB IBAT VUSUS -330mA 144mA 100μs/div 0V 475mA 3V 5V/div 0A 0A VUSUS 500mA/div IUSB 2V/div 3.7V 500mA/div IBAT -475mA USB RESUME MAX8903A toc27 3V 5V/div CUSB CHARGING 475mA 0A 3.6V VSYS IBAT 500mA/div MAX8903A toc28 0V 3.8V 500mA/div 3.6V 2V/div 0A 200μs/div BATTERY CHARGER SOFT-START -475mA 500mA/div 200μs/div Pin Description PIN NAME 1, 2 PG FUNCTION Power Ground for Step-Down Low-Side Synchronous n-Channel MOSFET. Both PG pins must be connected together externally. DC Power Input. DC is capable of delivering up to 2A to SYS. DC supports both AC adapter and USB inputs. The DC current limit is set through DCM, IUSB, or IDC depending on the input source used. See Table 2. Both DC pins must be connected together externally. Connect at least a 4.7μF ceramic capacitor from DC to PG. Current-Limit Mode Setting for the DC Power Input. When logic-high, the DC input current limit is set by the resistance from IDC to GND. When logic-low, the DC input current limit is internally programmed to 500mA or 100mA, as set by the IUSB logic input. There is an internal diode from DCM (anode) to DC (cathode) as shown in Figure 1. 3, 4 DC 5 DCM 6 BST High-Side MOSFET Driver Supply. Bypass BST to LX with a 0.1μF ceramic capacitor. 7 IUSB USB Current-Limit Set Input. Drive IUSB logic-low to set the USB current limit to 100mA. Drive IUSB logichigh to set the USB current limit to 500mA. 8 DOK DC Power-OK Output. Active-low open-drain output pulls low when a valid input is detected at DC. DOK is still valid when the charger is disabled (CEN high). 9 VL Logic LDO Output. VL is the output of an LDO that powers the MAX8903_ internal circuitry and charges the BST capacitor. Connect a 1μF ceramic capacitor from VL to GND. 10 CT Charge Timer Set Input. A capacitor (CCT) from CT to GND sets the fast-charge and prequal fault timers. Connect to GND to disable the timer. 11 IDC DC Current-Limit Set Input. Connect a resistor (RIDC) from IDC to GND to program the current limit of the step-down regulator from 0.5A to 2A when DCM is logic-high. 12 GND Ground. GND is the low-noise ground connection for the internal circuitry. ______________________________________________________________________________________ 11 MAX8903A–E/G/H/J/N/Y Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power MAX8903A–E/G/H/J/N/Y Pin Description (continued) PIN NAME 13 ISET Charge Current Set Input. A resistor (RISET) from ISET to GND programs the fast-charge current up to 2A. The prequal charge current is 10% of the fast-charge current. 14 CEN Charger Enable Input. Connect CEN to GND to enable battery charging when a valid source is connected at DC or USB. Connect to VL, or drive high to disable battery charging. 15 USUS USB Suspend Input. Drive USUS logic-high to enter USB suspend mode, lowering USB current to 115µA, and internally shorting SYS to BAT. 16 THM Thermistor Input. Connect a negative temperature coefficient (NTC) thermistor from THM to GND. Connect a resistor equal to the thermistor +25°C resistance from THM to VL. Charging is suspended when the thermistor is outside the hot and cold limits. Connect THM to GND to disable the thermistor temperature sensor. 17 USB USB Power Input. USB is capable of delivering 100mA or 500mA to SYS as set by the IUSB logic input. Connect a 4.7µF ceramic capacitor from USB to GND. 18 FLT Fault Output. Active-low, open-drain output pulls low when the battery timer expires before prequal or fast-charge completes. 19 UOK USB Power-OK Output. Active-low, open-drain output pulls low when a valid input is detected at USB. UOK is still valid when the charger is disabled (CEN high). 20, 21 BAT Battery Connection. Connect to a single-cell Li+ battery. The battery charges from SYS when a valid source is present at DC or USB. BAT powers SYS when neither DC nor USB power is present, or when the SYS load exceeds the input current limit. Both BAT pins must be connected together externally. 22 CHG Charger Status Output. Active-low, open-drain output pulls low when the battery is in fast-charge or prequal. Otherwise, CHG is high impedance. 23, 24 SYS System Supply Output. SYS connects to BAT through an internal 50mΩ system load switch when DC or USB are invalid, or when the SYS load is greater than the input current limit. When a valid voltage is present at DC or USB, SYS is limited to VSYSREG. When the system load (ISYS) exceeds the DC or USB current limit, SYS is regulated to 50mV below BAT, and both the powered input and the battery service SYS. Bypass SYS to GND with an X5R or X7R ceramic capacitor. See Table 6 for the minimum recommended SYS capacitor (CSYS). Both SYS pins must be connected together externally. 25, 26 CS 70mΩ Current-Sense Input. Connect the step-down inductor from LX to CS. When the step-down regulator is on, there is a 70mΩ current-sense MOSFET from CS to SYS. When the step-down regulator is off, the internal CS MOSFET turns off to block current from SYS back to DC. 27, 28 LX Inductor Connection. Connect the inductor between LX and CS. Both LX pins must be connected together externally. — EP Exposed Pad. Connect the exposed pad to GND. Connecting the exposed pad does not remove the requirement for proper ground connections to the appropriate pins. 12 FUNCTION ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power AC ADAPTER DC LX BST CS MAX8903_ DC POWER MANAGEMENT PWR OK SYS Li+ BATTERY CHARGER AND SYS LOAD SWITCH PWM STEP-DOWN REGULATOR DOK MAX8903A–E/G/H/J/N/Y PG CHARGER CURRENTVOLTAGE CONTROL SET INPUT LIMIT TO SYSTEM LOAD ISET BATTERY CONNECTOR BAT BAT+ + BAT- USB USB POWER MANAGEMENT USB PWR OK THERMISTOR MONITOR (SEE FIGURE 7) CURRENTLIMITED VOLTAGE REGULATOR UOK IC THERMAL REGULATION NTC VL CHARGE TERMINATION AND MONITOR SET INPUT LIMIT T THM CHG DC DC MODE USB LIMIT 500mA DCM IUSB 100mA USB SUSPEND USUS FLT CHARGE TIMER INPUT AND CHARGER CURRENT-LIMIT SET LOGIC CT CEN IDC GND DC LIMIT EP Figure 1. Functional Block Diagram ______________________________________________________________________________________ 13 MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power RPU 4 x 100kΩ 1 2 PG PG MAX8903_ CDC 4.7μF DOK 4 DC 6 CBST 0.1μF FLT UOK 3 DC ADAPTER TO VL CHG BST 27 LX ISET 18 19 25 CS (SEE TABLE 5 FOR INDUCTOR SELECTION) 26 CS IDC USB PWR OK 8 DC PWR OK 22 CHARGE INDICATOR 13 RISET 11 RIDC 28 LX L1 1μH FAULT OUTPUT SYS 24 SYS 23 BAT 21 BAT 20 TO SYSTEM LOAD CSYS (SEE TABLE 6 FOR CSYS SELECTION) USB 17 VBUS USB CUSB 4.7μF GND TO DC 5 OFF CHARGE ON 14 500mA 100mA 7 USB SUSPEND 15 10 CCT 0.15μF CBAT 10μF 1-CELL LI+ DCM VL 9 CVL 1μF CEN THM IUSB RT 10kΩ 16 NTC 10kΩ USUS CT GND 12 EP Figure 2. Typical Application Circuit Using a Separate DC and USB Connector Circuit Description The MAX8903_ is a dual input charger with a 16V input for a wide range of DC sources and USB inputs. The IC includes a high-voltage (16V) input DC-DC step-down converter that reduces charger power dissipation while also supplying power to the system load. The stepdown converter supplies up to 2A to the system, the battery, or a combination of both. 14 A USB charge input can charge the battery and power the system from a USB power source. When powered from USB or the DC input, system load current peaks that exceed what can be supplied by the input are supplemented by the battery. The MAX8903_ also manages load switching from the battery to and from an external power source with an on-chip 50mΩ MOSFET. This switch also helps support load peaks using battery power when the input source is overloaded. ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power 1 2 CDC 4.7μF VBUS CBST 0.1μF ID GND FLT UOK 3 DC DOK CHG BST 27 LX ISET 18 499kΩ 25 CS 26 CS IDC (SEE TABLE 5 FOR INDUCTOR VALUE SELECTION) 17 USB ADAPTER 5 OFF CHARGE ON 14 500mA 100mA 7 USB SUSPEND 15 10 CCT 0.15μF USB FAULT OUTPUT 19 USB PWR-OK 8 DC PWR-OK 22 CHARGE INDICATOR 13 RISET 11 RIDC 28 LX L1 1μH DC MODE PG MAX8903_ 6 D+ TO VL PG 4 DC D- MAX8903A–E/G/H/J/N/Y RPU 4 x 100kΩ SYS 24 SYS 23 BAT 21 BAT 20 TO SYSTEM LOAD CSYS (SEE TABLE 6 FOR CSYS SELECTION) CBAT 10μF 1-CELL LI+ DCM VL 9 CVL 1μF CEN THM IUSB RT 10kΩ 16 NTC 10kΩ USUS CT GND 12 EP Figure 3. Typical Application Circuit Using a Mini 5 Style Connector or Other DC/USB Common Connector As shown in Figure 1, the IC includes a full-featured charger with thermistor monitor, fault timer, charger status, and fault outputs. Also included are power-OK signals for both USB and DC. Flexibility is maintained with adjustable charge current, input current limit, and a minimum system voltage (when charging is scaled back to hold the system voltage up). The MAX8903_ prevents overheating during high ambient temperatures by limiting charging current when the die temperature exceeds +100°C. DC Input—Fast Hysteretic Step-Down Regulator If a valid DC input is present, the USB power path is turned off and power for SYS and battery charging is supplied by the high-frequency step-down regulator from DC. If the battery voltage is above the minimum system voltage (VSYSMIN, Figure 4), the battery charger connects the system voltage to the battery for lowest power dissipation. The step-down regulation point is then controlled by three feedback signals: maximum step-down output current programmed at IDC, maximum charger current programmed at ISET, and maximum ______________________________________________________________________________________ 15 MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Table 1. External Components List for Figures 2 and 3 COMPONENT (FIGURES 2 AND 3) CDC, CUSB FUNCTION PART Input filter capacitor 4.7µF ceramic capacitor CVL VL filter capacitor 1.0µF ceramic capacitor CSYS SYS output bypass capacitor 10µF (MAX8903A/MAX8903C/MAX8903D/MAX8903H/MAX8903J) or 22µF (MAX8903B/MAX8903E/MAX8903G/MAX8903Y) ceramic capacitor CBAT Battery bypass capacitor 10µF ceramic capacitor CCT Charger timing capacitor 0.15µF low TC ceramic capacitor Logic output pullup resistors 100kΩ RPU (X4) THM Negative TC thermistor Philips NTC thermistor, P/N 2322-640-63103, 0kΩ ±5% at +25°C 10kΩ RIDC THM pullup resistor DC input current-limit programming RISET Fast-charge current programming 1.2kΩ ±1%, for 1A charging DC input step-down inductor 1µH inductor with ISAT > 2A RT L1 3kΩ ±1%, for 2A limit die temperature. The feedback signal requiring the smallest current controls the average output current in the inductor. This scheme minimizes total power dissipation for battery charging and allows the battery to absorb any load transients with minimum system voltage disturbance. If the battery voltage is below VSYSMIN, the charger does not directly connect the system voltage to the battery and the system voltage (VSYS) is slightly above VSYSMIN as shown in Figure 4. The battery charger independently controls the battery charging current. VSYSMIN is set to either 3.0V or 3.4V based on the version of MAX8903_. See Table 6. After the battery charges to 50mV above VSYSMIN, the system voltage is connected to the battery. The battery fast-charge current then controls the step-down converter to set the average inductor current so that both the programmed input current limit and fast-charge current limit are satisfied. DC-DC Step-Down Control Scheme A proprietary hysteretic current PWM control scheme ensures fast switching and physically tiny external components. The feedback control signal that requires the smallest input current controls the center of the peak and valley currents in the inductor. The ripple current is internally set to provide 4MHz operation. When the input voltage decreases near the output voltage, very high duty cycle occurs and, due to minimum off-time, 4MHz operation is not achievable. The controller then provides minimum off-time, peak current regulation. Similarly, when the input voltage is too high to allow 4MHz operation due to the minimum on-time, the con16 troller becomes a minimum on-time, valley current regulator. In this way, ripple current in the inductor is always as small as possible to reduce ripple voltage on SYS for a given capacitance. The ripple current is made to vary with input voltage and output voltage in a way that reduces frequency variation. However, the frequency still varies somewhat with operating conditions. See the Typical Operating Characteristics. DC Mode (DCM) As shown in Table 2, the DC input supports both AC adapters (up to 2A) and USB (up to 500mA). With the DCM logic input set high, the DC input is in adapter mode and the DC input current limit is set by the resistance from IDC to GND (RIDC). Calculate RIDC according to the following equation: RIDC = 6000V/IDC-MAX With the DCM logic input set low, the DC input current limit is internally programmed to 500mA or 100mA as set by the IUSB logic input. With the IUSB logic input set high, the DC input current limit is 500mA and the DC input delivers current to SYS through the step-down regulator. With the IUSB logic input set low, the DC input current limit is 100mA. In this 100mA mode, the step-down regulator is turned off and its high-side switch operates as a linear regulator with a 100mA current limit. The linear regulator’s output is connected to LX and its output current flows through the inductor into CS and finally to SYS. The DCM pin has an internal diode to DC as shown in Figure 1. To prevent current from flowing from DCM through the internal diode and to the DC input, DCM cannot be driven to a voltage higher than DC. The ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power USB Input—Linear Regulator If a valid USB input is present with no valid DC input, current for SYS and battery charging is supplied by a low-dropout linear regulator connected from USB to SYS. The SYS regulation voltage shows the same characteristic as when powering from the DC input (see Figure 4). The battery charger operates from SYS with any extra available current, while not exceeding the maximum-allowed USB current. If both USB and DC inputs are valid, power is only taken from the DC input. The maximum USB input current is set by the logic state of the IUSB input to either 100mA or 500mA. Power Monitor Outputs (UOK, DOK) DOK is an open-drain, active-low output that indicates the DC input power status. With no source at the USB pin, the source at DC is considered valid and DOK is driven low when: 4.15V < VDC < 16V. When the USB voltage is also valid, the DC source is considered valid and DOK is driven low when: 4.45V < VDC < 16V. The higher minimum DC voltage with USB present helps guarantee cleaner transitions between input supplies. If the DC power-OK output feature is not required, connect DOK to ground. UOK is an open-drain, active-low output that indicates the USB input power status. UOK is low when a valid source is connected at USB. The source at USB is valid VSYSREG VBATREG MAX8903_ VSYS when 4.1V < VUSB < 6.6V. If the USB power-OK output feature is not required, connect UOK to ground. Both the UOK and the DOK circuitry remain active in thermal overload, USB suspend, and when the charger is disabled. DOK and UOK can also be wire-ORed together to generate a single power-OK (POK) output. Thermal Limiting When the die temperature exceeds +100°C, a thermal limiting circuit reduces the input current limit by 5%/°C, bringing the charge current to 0mA at +120°C. Since the system load gets priority over battery charging, the battery charge current is reduced to 0mA before the input limiter drops the load voltage at SYS. To avoid false charge termination, the charge termination detect function is disabled in this mode. If the junction temperature rises beyond +120°C, no current is drawn from DC or USB, and VSYS regulates at 50mV below VBAT. System Voltage Switching DC Input When charging from the DC input, if the battery is above the minimum system voltage, SYS is connected to the battery. Current is provided to both SYS and the battery, up to the maximum program value. The stepdown output current sense and the charger current sense provide feedback to ensure the current loop demanding the lower input current is satisfied. The advantage of this approach when powering from DC is that power dissipation is dominated by the step-down regulator efficiency, since there is only a small voltage drop from SYS to BAT. Also, load transients can be absorbed by the battery while minimizing the voltage disturbance on SYS. If both the DC and USB inputs are valid, the DC input takes priority and delivers the input current, while the USB input is off. After the battery is done charging, the charger is turned off and the SYS load current is supplied from the DC input. The SYS voltage is regulated to VSYSREG. The charger turns on again after the battery drops to the restart threshold. If the load current exceeds the input limiter, SYS drops down to the battery voltage and the 50mΩ SYS-to-BAT PMOS switch turns on to supply the extra load current. The SYS-to-BAT switch turns off again once the load is below the input current limit. The 50mΩ PMOS also turns on if valid DC input power is removed. IBAT x RON VSYSMIN VBAT VCEN = 0V VDC AND/OR VUSB = 5.0V Figure 4. SYS Tracking VBAT to the Minimum System Voltage USB Input When charging from the USB input, the DC input stepdown regulator turns off and a linear regulator from USB to SYS powers the system and charges the battery. If the battery is greater than the minimum system voltage, the SYS voltage is connected to the battery. ______________________________________________________________________________________ 17 MAX8903A–E/G/H/J/N/Y through the internal diode to DC. This circuit of Figure 3 allows a microprocessor to drive the gate of the MOSFET to any state at any time. An alternative to the simple MOSFET and resistor on DCM as shown in Figure 3 is to place a 1MΩ resistor in series with the DCM input to the microprocessor. The microprocessor can then monitor the DOK output and make sure that whenever DOK is high DCM is also low. In the event that DCM is driven to a higher voltage than DC, the 1MΩ series resistance limits the current from DCM through the internal diode to DC to a few μA. MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Table 2. Input Limiter Control Logic POWER SOURCE AC Adapter at DC Input DC STEP-DOWN OUTPUT CURRENT LIMIT DOK UOK DCM*** L X H X X 6000V/RIDC L X L L L 100mA L X L H L 500mA L X L X H USB suspend IUSB USUS USB INPUT CURRENT LIMIT Lesser of 1200V/RISET and 6000V/RIDC USB input off. DC input has priority. USB Power at DC Input Lesser of 1200V/RISET and 100mA Lesser of 1200V/RISET and 500mA 0 100mA Lesser of 1200V/RISET and 100mA H L X L L H L X H L H L X X H USB suspend Lesser of 1200V/RISET and 500mA 0 H H X X X No USB input 0 USB Power at USB Input, DC Unconnected DC and USB Unconnected MAXIMUM CHARGE CURRENT** No DC input 500mA **Charge current cannot exceed the input current limit. Charge may be less than the maximum charge current if the total SYS load exceeds the input current limit. ***There is an internal diode from DCM (anode) to DC (cathode) as shown in Figure 1. If the DCM level needs to be set by a μP, use a MOSFET for isolation as shown in FIgure 3. X = Don’t care. The USB input then supplies the SYS load and charges the battery with any extra available current, while not exceeding the maximum-allowed USB current. Load transients can be absorbed by the battery while minimizing the voltage disturbance on SYS. When battery charging is completed, or the charger is disabled, SYS is regulated to VSYSREG. If both USB and DC inputs are valid, power is only taken from the DC input. USB Suspend Driving USUS high and DCM low turns off charging as well as the SYS output and reduces input current to 170μA to accommodate USB suspend mode. See Table 2 for settings. Charge Enable (CEN) When CEN is low, the charger is on. When CEN is high, the charger turns off. CEN does not affect the SYS output. In many systems, there is no need for the system controller (typically a microprocessor) to disable the charger, because the MAX8903_ smart power selector 18 circuitry independently manages charging and adapter/battery power hand-off. In these situations, CEN may be connected to ground. Soft-Start To prevent input transients that can cause instability in the USB or AC adapter power source, the rate of change of the input current and charge current is limited. When an input source is valid, SYS current is ramped from zero to the set current-limit value in typically 50μs. This also means that if DC becomes valid after USB, the SYS current limit is ramped down to zero before switching from the USB to DC input. At some point, SYS is no longer able to support the load and may switch over to BAT. The switchover to BAT occurs when VSYS < VBAT. This threshold is a function of the SYS capacitor size and SYS load. The SYS current limit then ramps from zero to the set current level and SYS supports the load again as long as the SYS load current is less than the set current limit. ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Battery Charger While a valid input source is present, the battery charger attempts to charge the battery with a fast-charge current determined by the resistance from ISET to GND. Calculate the RISET resistance according to the following equation: RISET = 1200V/ICHGMAX Monitoring Charge Current The voltage from ISET to GND is a representation of the battery charge current and can be used to monitor the current charging the battery. A voltage of 1.5V represents the maximum fast-charge current. If necessary, the charge current is reduced automatically to prevent the SYS voltage from dropping. Therefore, a battery never charges at a rate beyond the capabilities of a 100mA or 500mA USB input, or overloads an AC adapter. See Figure 5. When VBAT is below VBATPQ, the charger enters prequal mode and the battery charges at 10% of the maximum fast-charge rate until the voltage of the deeply discharged battery recovers. When the battery voltage MONITORING THE BATTERY CHARGE CURRENT WITH VISET 1.5 VISET (V) 0 DISCHARGING 0 1200V/RISET BATTERY CHARGING CURRENT (A) reaches VBATREG and the charge current drops to 10% of the maximum fast-charge current, the charger enters the DONE state. The charger restarts a fast-charge cycle if the battery voltage drops by 100mV. Charge Termination When the charge current falls to the termination threshold (ITERM) and the charger is in voltage mode, charging is complete. Charging continues for a brief 15s top-off period and then enters the DONE state where charging stops. Note that if charge current falls to ITERM as a result of the input or thermal limiter, the charger does not enter DONE. For the charger to enter DONE, charge current must be less than ITERM, the charger must be in voltage mode, and the input or thermal limiter must not be reducing charge current. Charge Status Outputs Charge Output (CHG) CHG is an open-drain, active-low output that indicates charger status. CHG is low when the battery charger is in its prequalification and fast-charge states. CHG goes high impedance if the thermistor causes the charger to go into temperature suspend mode. When used in conjunction with a microprocessor (μP), connect a pullup resistor between CHG and the logic I/O voltage to indicate charge status to the μP. Alternatively, CHG can sink up to 20mA for an LED charge indicator. Fault Output (FLT) FLT is an open-drain, active-low output that indicates charger status. FLT is low when the battery charger has entered a fault state when the charge timer expires. This can occur when the charger remains in its prequal state for more than 33 minutes or if the charger remains in fast-charge state for more than 660 minutes (see Figure 6). To exit this fault state, toggle CEN or remove and reconnect the input source. When used in conjunction with a microprocessor (μP), connect a pullup resistor between FLT and the logic I/O voltage to indicate charge status to the μP. Alternatively, FLT can sink up to 20mA for an LED fault indicator. If the FLT output is not required, connect FLT to ground or leave unconnected. Charge Timer A fault timer prevents the battery from charging indefinitely. The fault prequal and fast-charge timers are controlled by the capacitance at CT (CCT). Figure 5. Monitoring the Battery Charge Current with the Voltage from ISET to GND ______________________________________________________________________________________ 19 MAX8903A–E/G/H/J/N/Y When the charger is turned on, the charge current ramps from 0A to the ISET current value in typically 1.0ms. Charge current also soft-starts when transitioning to fastcharge from prequal, when the input power source is switched between USB and DC, and when changing the USB charge current from 100mA to 500mA with the IUSB logic input. There is no di/dt limiting, however, if RISET is changed suddenly using a switch. MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power NOT READY UOK AND DOK = HIGH IMPEDANCE CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE ICHG = 0mA CEN = HI OR REMOVE AND RECONNECT THE INPUT SOURCE(S) UOK AND/OR DOK = LOW CEN = 0 RESET TIMER PREQUALIFICATION UOK AND/OR DOK = LOW CHG = LOW FLT = HIGH IMPEDANCE 0 < VBAT < VBATPQ ICHG ≤ ICHGMAX/10 VBAT < VBATPQ - 180mV RESET TIMER = 0 VBAT < VBATPQ - 180mV RESET TIMER ICHG > ITERM RESET TIMER ANY CHARGING STATE THM OK TIMER RESUME THM NOT OK TIMER SUSPEND TEMPERATURE SUSPEND ICHG = 0mA UOK OR DOK PREVIOUS STATE CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE TOGGLE CEN OR REMOVE AND RECONNECT THE INPUT SOURCE(S) TIMER > tPREQUAL FAULT UOK AND/OR DOK = LOW CHG = HIGH IMPEDANCE FLT = LOW ICHG = 0mA VBAT > VBATPQ RESET TIMER FAST-CHARGE UOK AND/OR DOK = LOW CHG = LOW FLT = HIGH IMPEDANCE VBATPQ < VBAT < VBATREG ICHG ≤ ICHGMAX ANY STATE TIMER > tFSTCHG (TIMER SLOWED BY 2x IF ICHG < ICHGMAX/2, AND PAUSED IF ICHG < ICHGMAX/5 WHILE VBAT < VBATREG) ICHG < ITERM AND VBAT = VBATREG AND THERMAL OR INPUT LIMIT NOT EXCEEDED; RESET TIMER TOP-OFF UOK AND/OR DOK = LOW CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE VBAT = VBATREG ICHG = ITERM VBAT < VBATREG + VRSTRT RESET TIMER TIMER > tTOP-OFF DONE UOK AND/OR DOK = 0 CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE VBATREG + VRSTRT < VBAT < VBATREG ICHG = 0mA Figure 6. MAX8903A Charger State Flow Chart CCT 0.15μF CCT tFST -CHG = 660min × 0.15μF t TOP -OFF = 15s (MAX 8903 A/D /H/ J/N/ Y) tPREQUAL = 33min × t TOP -OFF = 132min × 20 CCT (MAX8903B/E / G) 0.15μF While in fast-charge mode, a large system load or device self-heating may cause the MAX8903_ to reduce charge current. Under these circumstances, the fast-charge timer is slowed by 2x if the charge current drops below 50% of the programmed fast-charge level, and suspended if the charge current drops below 20% of the programmed level. The fast-charge timer is not affected at any current if the charger is regulating the BAT voltage at VBATREG (i.e., the charger is in voltage mode). ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power MAX8903A–E/G/H/J/N/Y CEN VL THERMISTOR CIRCUITRY VL MAX8903_ 0.87 VL RTB ALTERNATE THERMISTOR CONNECTION 0.74 VL MAX8903B/MAX8903E/ MAX8903G ONLY THERMISTOR DETECTOR COLD THM RTS 0.28 VL RTP RT HOT ENABLE THM 0.03 VL RT THM OUT OF RANGE DISABLE CHARGER ALL COMPARATORS 60mV HYSTERESIS GND Figure 7. Thermistor Monitor Circuitry Table 3. Fault Temperatures for Different Thermistors Thermistor β (K) 3000 3250 3500 3750 4250 RTB (kΩ) (Figure 7) 10 10 10 10 10 Resistance at +25°C (kΩ) 10 10 10 10 10 Resistance at +50°C (kΩ) 4.59 4.30 4.03 3.78 3.316 Resistance at 0°C (kΩ) 29.32 31.66 36.91 25.14 27.15 Nominal Hot Trip Temperature (°C) 55 53 50 49 46 Nominal Cold Trip Temperature (°C) -3 -1 0 2 4.5 VL Regulator VL is a 5V linear regulator that powers the MAX8903’s internal circuitry and charges the BST capacitor. VL is used externally to bias the battery’s thermistor. VL takes its input power from USB or DC. When input power is available from both USB and DC, VL takes power from DC. VL is enabled whenever the input voltage at USB or DC is greater than ~1.5V. VL does not turn off when the input voltage is above the overvoltage threshold. Similarly, VL does not turn off when the charger is disabled (CEN = high). Connect a 1μF ceramic capacitor from VL to GND. Thermistor Input (THM) The THM input connects to an external negative temperature coefficient (NTC) thermistor to monitor battery or system temperature. Charging is suspended when the thermistor temperature is out of range. The charge timers are suspended and hold their state but no fault is indicated. When the thermistor comes back into range, charging resumes and the charge timer continues from where it left off. Connecting THM to GND disables the thermistor monitoring function. Table 3 lists the fault temperature of different thermistors. Since the thermistor monitoring circuit employs an external bias resistor from THM to VL (RTB, Figure 7), the thermistor is not limited only to 10kΩ (at +25°C). Any resistance thermistor can be used as long as the value is equivalent to the thermistor’s +25°C resistance. For example, with a 10kΩ at +25°C thermistor, use 10kΩ at RTB, and with a 100kΩ at +25°C thermistor, use 100kΩ. For a typical 10kΩ (at +25°C) thermistor and a 10kΩ RTB resistor, the charger enters a temperature suspend state when the thermistor resistance falls below 3.97kΩ (too hot) or rises above 28.7kΩ (too cold). This corresponds to a 0°C to +50°C range when using a 10kΩ NTC thermistor with a beta of 3500. The general relation of thermistor resistance to temperature is defined by the following equation: ⎧ ⎛ 1 1 ⎞⎫ − ⎨β ⎜ ⎟⎬ ⎝ T C + ° °C ⎠ ⎭⎪ 273 298 RT = R25 × e ⎩⎪ ______________________________________________________________________________________ 21 MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power where: RT = The resistance in Ω of the thermistor at temperature T in Celsius R25 = The resistance in Ω of the thermistor at +25°C β = The material constant of the thermistor, which typically ranges from 3000K to 5000K T = The temperature of the thermistor in °C Table 3 shows the MAX8903_ THM temperature limits for different thermistor material constants. and let the system continue to operate with external power. If the THM pin is tied to GND (voltage at THM is below 3% of VL), the thermistor option is disabled and the system does not respond to the thermistor input. In those cases, it is assumed that the system has its own temperature sensing, and halts changing through CEN when the temperature is outside of the safe charging range. Some designs might prefer other thermistor temperature limits. Threshold adjustment can be accommodated by changing RTB, connecting a resistor in series and/or in parallel with the thermistor, or using a thermistor with different β. For example, a +45°C hot threshold and 0°C cold threshold can be realized by using a thermistor with a β of 4250 and connecting 120kΩ in parallel. Since the thermistor resistance near 0°C is much higher than it is near +50°C, a large parallel resistance lowers the cold threshold, while only slightly lowering the hot threshold. Conversely, a small series resistance raises the hot threshold, while only slightly raising the cold threshold. Raising RTB lowers both the cold and hot thresholds, while lowering RTB raises both thresholds. Note that since VL is active whenever valid input power is connected at DC or USB, thermistor bias current flows at all times, even when charging is disabled (CEN = high). When using a 10kΩ thermistor and a 10kΩ pullup to VL, this results in an additional 250μA load. This load can be reduced to 25μA by instead using a 100kΩ thermistor and 100kΩ pullup resistor. 28-PIN 4mm x 4mm THIN QFN Power Enable on Battery Detection The power enabled on battery detection function allows the MAX8903B/MAX8903E/MAX8903G to automatically enable/disable the USB and DC power inputs when the battery is applied/removed. This function utilizes the battery pack’s integrated thermistor as a sensing mechanism to determine when the battery is applied or removed. With this function, MAX8903B/MAX8903E/ MAX8903G-based systems shut down when the battery is removed regardless of whether external power is available at the USB or DC power inputs. The MAX8903B/MAX8903E/MAX8903G implement the power enabled on battery detection function with the thermistor detector comparator as shown in Figure 7. If no battery is present, the absence of the thermistor allows RTB to pull THM to VL. When the voltage at the THM pin increases above 87% of VL, it is assumed that the battery has been removed and the system powers down. However, there is also the option to bypass this thermistor sensing option completely, and so retain the ability to remove the battery 22 Power Dissipation Table 4. Package Thermal Characteristics Continuous Power Dissipation SINGLE-LAYER PCB MULTILAYER PCB 1666.7mW 2286mW Derate 20.8mW/°C above +70°C Derate 28.6mW/°C above +70°C θJA 48°C/W 35°C/W θJC 3°C/W 3°C/W Minimum SYS Output Capacitor Based on the version of the MAX8903_, the SYS load regulation is either 25mV/A or 40mV/A. The 25mV/A versions achieve better load regulation by increasing the feedback loop gain. To ensure feedback stability with this higher gain, a larger SYS output capacitor is required. Devices with 25m/V SYS load regulation require 22μF SYS output capacitor whereas devices with 40m/V only require 10μF. See Table 6 for more information about the various versions of the MAX8903_. Inductor Selection for Step-Down DC-DC Regulator The MAX8903_'s control scheme requires an external inductor (LOUT) from 1.0μH to 10μH for proper operation. This section describes the control scheme and the considerations for inductor selection. Table 5 shows recommended inductors for typical applications. For assistance with the calculations needed to select the optimum inductor for a given application, refer to the spreadsheet at: www.maxim-ic.com/tools/other/software/MAX8903-inductor-design.xls. The MAX8903 step-down DC-DC regulator implements a control scheme that typically results in a constant switching frequency (fSW). When the input voltage decreases to a value near the output voltage, high duty cycle operation occurs and the device can operate at less than fSW due to minimum off-time (tOFFMIN) constraints. In high duty cycle operation, the regulator operates with tOFFMIN and a peak current regulation. Similarly, when the input voltage is too high to allow fSW operation due to minimum ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Versions of the MAX8903 with fSW = 4MHz offer the smallest LOUT while delivering good efficiency with low input voltages (5V or 9V). For applications that use high input voltages (12V), the MAX8903G with fSW = 1MHz is the best choice because of its higher efficiency. For a given maximum output voltage, the minimum inductor ripple current condition occurs at the lowest input voltage that allows the regulator to maintain fSW operation. If the minimum input voltage dictates an offtime less than tOFFMIN, then the minimum inductor ripple condition occurs just before the regulator enters fixed minimum off-time operation. To allow the currentmode regulator to provide a low-jitter, stable duty factor operation, the minimum inductor ripple current (IL_RIPPLE_MIN) should be greater than 150mA in the minimum inductor ripple current condition. The maximum allowed output inductance LOUT_MAX is therefore obtained using the equations (1) and (2) below. (1) ⎛ VSYS(MAX) ⎞ 1 tOFF = tOFFMIN if ⎜ 1 − ≤ tOFFMIN , ⎟× V f ⎝ DC(MIN) ⎠ SW ( VDC(MAX) − VSYS(MIN) ) × tON K × ISDLIM where VDC(MAX) is maximum input voltage, VSYS(MIN) is the minimum charger output voltage, and tON is the ontime at high input voltage, as given by the following equation: (5) ⎛ VSYS(MIN) 1 ⎞ tON = tONMIN if ⎜ × ⎟ ≤ tONMIN , ⎝ VDC(MAX) fSW ⎠ otherwise, tON = VSYS(MIN) VDC(MAX) × 1 fSW The saturation current DC rating of the inductor (ISAT) must be greater than the DC step-down output current limit (ISDLIM) plus one-half the maximum ripple current, as given by equation (6). (6) ISAT > ISDLIM + ILRIPPLE _ MAX 2 where ILRIPPLE_MAX is the greater of the ripple currents obtained from (7) and (8). otherwise, ⎛ VSYS(MAX) ⎞ 1 tOFF = ⎜ 1 − ⎟× V f ⎝ DC(MIN) ⎠ SW where tOFF is the off-time, VSYS(MAX) is maximum charger output voltage, and VDC(MIN) is minimum DC input voltage. (2) (4) LOUT _ MIN _ t = ON LOUT _ MAX = VSYS(MAX) × tOFF IL _ RIPPLE _ MIN where LOUT_MAX is the maximum allowed inductance. To obtain a small-sized inductor with acceptable core loss, while providing stable, jitter-free operation at the advertised fSW, the actual output inductance (LOUT), is obtained by choosing an appropriate ripple factor K, and picking an available inductor in the range inductance yielded by equations (2), (3), and (4). LOUT should also not be lower than the minimum allowable inductance as shown in Table 6. The recommended ripple factor ranges from (0.2 ≤ K 0.45) for (2A ≥ ISDLIM ≥ 1A) designs. (3) VSYS(MAX) × tOFF LOUT _ MIN _ TOFF = K × ISDLIM (7) (8) ILRIPPLE _ MIN _ TOFF = ILRIPPLE _ MIN _ TON = VSYS(MAX) × tOFF LOUT ( VDC(MAX) − VSYS(MIN) ) × tON LOUT PCB Layout and Routing Good design minimizes ground bounce and voltage gradients in the ground plane, which can result in instability or regulation errors. The GND and PGs should connect to the power-ground plane at only one point to minimize the effects of power-ground currents. Battery ground should connect directly to the power-ground plane. The ISET and IDC current-setting resistors should connect directly to GND to avoid current errors. Connect GND to the exposed pad directly under the IC. Use multiple tightly spaced vias to the ground plane under the exposed pad to help cool the IC. Position input capacitors from DC, SYS, BAT, and USB to the power-ground plane as close as possible to the IC. Keep high current traces such as those to DC, SYS, and BAT as short and wide as possible. Refer to the MAX8903A Evaluation Kit for a suitable PCB layout example. where tOFF is the minimum off-time obtained from (1). ______________________________________________________________________________________ 23 MAX8903A–E/G/H/J/N/Y on-time constraints (tONMIN), the regulator becomes a fixed minimum on-time valley current regulator. MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Selector Guide The MAX8903_ is available in several options designated by the first letter following the root part number. The basic architecture and functionality of the MAX8903A–MAX8903E/MAX8903G/MAX8903Y are the same. Their differences lie in certain electrical and operational parameters. Table 6 outlines these differences. Table 5. Recommended Inductor Examples DC INPUT VOLTAGE RANGE 5V ±10% 5V ±10% 5V ±10% 5V ±10% 9V ±10% 9V ±10% 24 DC STEP-DOWN OUTPUT CURRENT LIMIT (ISDMAX) PART NUMBER, SWITCHING FREQUENCY* RECOMMENDED INDUCTOR MAX8903H/J/N/Y, 4MHz 1.0μH, IFSC1008ABER1R0M01, Vishay 2.5mm x 2mm x 1.2mm, 43mΩ (max), 2.6A or 1.0μH, LQH32PN1R0-NN0, Murata, 3.2mm x 2.5mm x 1.55mm, 54mΩ (max), 2.3A 1A MAX8903H/J/N/Y, 4MHz 1.5μH inductor, MDT2520-CN1R5M, TOKO 2.5mm x 2.0mm x 1.2mm, 123.5mΩ (max), 1.25A or 1.5uH Inductor, IFSC1008ABER1R5M01, Vishay 2.5mm x 2mm x 1.2mm, 72mΩ (max), 2.2A 2A MAX8903A/B/C/D/E, 4MHz 2.2μH inductor, DFE322512C-2R2N, TOKO 3.2mm x 2.5mm x 1.2mm, 91mΩ (max), 2.4A or 2.2μH inductor, IFSC1515AHER2R2M01, Vishay 3.8mm x 3.8mm x 1.8mm, 45mΩ (max), 3A 1A MAX8903A/B/C/D/E, 4MHz 2.2μH inductor, IFSC1008ABER2R2M01, Vishay 2.5mm x 2mm x 1.2mm, 90mΩ (max), 2.15A or 2.2μH Inductor, LQH32PN2R2-NN0, Murata 3.2mm x 2.5mm x 1.55mm, 91mΩ (max), 1.55A MAX8903H/J/N/Y, 4MHz 1.5uH inductor, IFSC1008ABER1R5M01, Vishay 2.5mm x 2mm x 1.2mm, 72mW (max), 2.2A or 1.5μH Inductor, VLS4012ET-1R5N, TDK 4mm x 4mm x 1.2mm, 72mW (max), 2.1A MAX8903H/J/N/Y, 4MHz 2.2μH inductor, IFSC1008ABER2R2M01, Vishay 2.5mm x 2mm x 1.2mm, 90mΩ (max), 2.15A or 2.2μH inductor, LQH3NPN2R2NJ0, Murata 3mm x 3mm x 1.1mm, 83mΩ (max), 1.15A 2A 2A 1A ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power DC INPUT VOLTAGE RANGE 9V ±10% 9V ±10% 9V ±10% 9V ±10% 12V ±10% 12V ±10% DC STEP-DOWN OUTPUT CURRENT LIMIT (ISDMAX) PART NUMBER, SWITCHING FREQUENCY* 2A MAX8903A/B/C/D/E, 4MHz 2.2μH inductor, DFE322512C-2R2N, TOKO 3.2mm x 2.5mm x 1.2mm, 91mΩ (max), 2.4A or 2.2μH Inductor, IFSC1515AHER2R2M01, Vishay 3.8mm x 3.8mm x 1.8mm, 45mΩ (max), 3A 1A MAX8903A/B/C/D/E, 4MHz 2.2μH Inductor, IFSC1008ABER2R2M01, Vishay 2.5mm x 2mm x 1.2mm, 90mΩ (max), 2.15A or 2.2μH Inductor, LQH3NPN2R2NJ0, Murata 3mm x 3mm x 1.1mm, 83mΩ (max), 1.15A 2A 1A 2A 1A MAX8903A–E/G/H/J/N/Y Table 5. Recommended Inductor Examples (continued) RECOMMENDED INDUCTOR MAX8903G, 1MHz 4.3uH Inductor, DEM4518C (1235AS-H-4R3M), TOKO 4.7mm x 4.5mm x 1.8mm, 84mΩ (max), 2.0A or 4.7μH Inductor, IFSC1515AHER4R7M01, Vishay 3.8mm x 3.8mm x 1.8mm, 90mΩ (max), 2.0A MAX8903G, 1MHz 4.7μH inductor, DEM2818C (1227AS-H-4R7M), TOKO 3.2mm x 2.8mm x 1.8mm, 92mΩ (max), 1.1A or 4.7μH inductor, IFSC1008ABER4R7M01, Vishay 2.5mm x 2mm x 1.2mm, 212mΩ (max), 1.2A MAX8903G, 1MHz 4.3μH inductor, DEM4518C (1235AS-H-4R3M), TOKO 4.7mm x 4.5mm x 1.8mm, 84mΩ (max), 2.0A or 4.7μH inductor, IFSC1515AHER4R7M01, Vishay 3.8mm x 3.8mm x 1.8mm, 90mΩ (max), 2.0A MAX8903G, 1MHz 6.8μH, IFSC1515AHER6R8M01, Vishay 3.8mm x 3.8mm x 1.8mm, 115mΩ (max), 1.5A or 6.8μH, LQH44PN6R8MP0, Murata 4mm x 4mm x 1.65mm, 144mΩ (max), 1.34A *See the Selector Guide for more information about part numbers. ______________________________________________________________________________________ 25 MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Selector Guide The MAX8903_ is available in several options designated by the first letter following the root part number. The basic architecture and functionality of the MAX8903A–MAX8903E/MAX8903G/MAX8903Y are the same. Their differences lie in certain electrical and operational parameters. Table 6 outlines these differences. Table 6. Selector Guide PARAMETER MAX8903A MAX8903B MAX8903C MAX8903D MAX8903E MAX8903G MAX8903H MAX8903J MAX8903N MAX8903Y Minimum SYS Regulation Voltage (VSYSMIN) 3.0V 3.0V 3.4V 3.4V 3.0V 3.0V 3.4V 3.4V 3.4V 3.0V SYS Regulation Voltage (VSYSREG) 4.4V 4.325V 4.4V 4.4V 4.325V 4.325V 4.4V 4.5V 4.4V 4.4V Minimum Allowable Inductor 2.2µH 2.2µH 2.2µH 2.2µH 2.2µH 2.2µH 1µH 1µH 1µH 1µH Switching Frequency 4MHz 4MHz 4MHz 4MHz 4MHz 1MHz 4MHz 4MHz 4MHz 4MHz SYS Load Regulation 40mV/A 25mV/A 40mV/A 40mV/A 25mV/A 25mV/A 40mV/A 25mV/A 25mV/A 25mV/A Minimum SYS Output Capacitor (CSYS) 10µF 22µF 10µF 10µF 22µF 22µF 10µF 10µF 22µF 22µF BAT Regulation Voltage (VBATREG) (Note 5) 4.2V 4.2V 4.2V 4.1V 4.1V 4.2V 4.2V 4.35V 4.15V 4.15V BAT Prequal Threshold (VBATPQ) (Note 5) 3V 2.5V 3V 3V 2.5V 2.5V 3V 3V 3V 3V Top-Off Timer (Note 6) 15s (fixed) 132min 15s (fixed) 15s (fixed) 132min 132min VL Output Current Rating 1mA 10mA 1mA 1mA 10mA 10mA 1mA 1mA 1mA 1mA Power-Enable On Battery Detection (Note 7) No Yes No No Yes Yes No No No No Comments — — — — — — (Note 8) — — — Note 5: Note 6: Note 7: Note 8: 26 15s (fixed) 15s (fixed) 15s (fixed) 15s (fixed) Typical values. See the Electrical Characteristics table for min/max values. Note that this also changes the timing for the prequal and fast-charge timers. See the Power Enable on Battery Detection section for details. The MAX8903H is a newer version of the MAX8903C that is a recommended for new designs. ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Chip Information USB THM USUS 20 UOK 21 FLT BAT TOP VIEW BAT PROCESS: BiCMOS 19 18 17 16 15 CHG 22 14 CEN SYS 23 13 ISET SYS 24 12 GND 11 IDC 10 CT MAX8903_ CS 25 CS 26 LX 27 EP 5 6 7 IUSB DC 4 BST 3 DCM 2 DC 1 PG + PG LX 28 9 VL 8 DOK TQFN ______________________________________________________________________________________ 27 MAX8903A–E/G/H/J/N/Y Pin Configuration MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Package Information For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 28 PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 28 TQFN-EP T2844-1 21-0139 90-0035 ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power ______________________________________________________________________________________ 29 MAX8903A–E/G/H/J/N/Y Package Information (continued) For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. MAX8903A–E/G/H/J/N/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Revision History REVISION NUMBER REVISION DATE 0 12/08 DESCRIPTION Initial release PAGES CHANGED — 1 8/09 Added MAX8903C/MAX8903D to data sheet 2 11/09 Made various corrections 1–20 3 10/10 Added MAX8903B, MAX8903E, MAX8903G, and MAX8903Y 1–29 4 5/11 Added MAX8903H and MAX8903J and updated components 1–29 5 9/11 Added the MAX8903N, and removed future product designation for MAX8903J 1–29 1–7, 9, 11–21 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. 30 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. 19-4413; Rev 2; 10/10 MAX8903A Evaluation Kit The MAX8903A evaluation kit (EV kit) is a fully assembled and tested circuit board for evaluating the 2A, 1-cell Li+ DC-DC battery charger. The EV kit charges a single-cell lithium-ion (Li+) battery from a DC input (AC adaptor) or a USB 100mA/500mA source and provides system power from the DC input, USB input, or battery. Battery charge current and SYS current limit are independently set. Charge current and DC converter output current limit can be set up to 2A, respectively. The USB input current can be set to 100mA or 500mA and USB suspend mode is also supported. Power not used by the system is available to charge the battery. The EV kit comes standard with the MAX8903A installed. However, the EV kit can also be used to evaluate the MAX8903B–MAX8903E and MAX8903Y by replacing the MAX8903A (U1) with the preferred IC. Features ♦ DC-DC Converter Output Current-Limit Adjustment Range of 0.5A to 2A (EV Kit Standard Configuration: 2A) ♦ Battery Charger Current-Limit Adjustment Range of 0.5A to 2A (EV Kit Standard Configuration: 1A) ♦ USB Current Limit of 100mA or 500mA ♦ Efficient 4MHz Switching DC-DC Converter Powers System Load and Charger ♦ Instant On—Works with No Battery or Low Battery ♦ 28-Pin, 4mm x 4mm Thin QFN Package with Exposed Pad ♦ Fully Assembled and Tested Ordering Information PART TYPE MAX8903AEVKIT+ EV Kit +Denotes lead(Pb)-free and RoHS compliant Component List DESIGNATION C1 C2 C3A, C4 C5, C7 Figure 1. MAX8903A EV Kit Photo C6 QTY DESCRIPTION 1 2.2μF ±10%, 16V X5R ceramic capacitor (0805) TDK C2012X7R1C225K or equivalent 1 4.7μF ±10%, 25V X5R ceramic capacitor (0805) Murata GRM21BR61E475KA12L or equivalent 2 10μF ±10%, 10V X5R ceramic capacitors (0805) Taiyo Yuden LMK212BJ106KG or equivalent 2 0.1μF ±10%, 10V X7R ceramic capacitors (0402) TDK C1005X5R1A104K or equivalent 1 2.2μF ±10%, 6.3V X5R ceramic capacitor (0603) Taiyo Yuden LMK107BJ225MA or equivalent ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 Evaluates: MAX8903A–MAX8903E/MAX8903Y General Description Evaluates: MAX8903A–MAX8903E/MAX8903Y MAX8903A Evaluation Kit Component List (continued) DESIGNATION QTY C8, C9, C11 0 Not installed, capacitors (0402) 1 4.7μF ±10%, 16V X5R ceramic capacitor (0805) Taiyo Yuden EMK212BJ475K or equivalent C10 D1, D3, D4 D2 J1, J2 DESCRIPTION DESIGNATION 3 Small green LEDs Panasonic LNJ308G8PRA 1 Small red LED Panasonic LNJ208R8ARA 2 USB type-AB right-angle mini jacks Molex 56579-0576 QTY DESCRIPTION L1 1 1μH, 2.8A, 54mΩ inductor (4.1mm x 4.1mm x 1.2mm) TOKO A1101AS-1R0 (DEA4012CK series) NTC 0 100kΩ NTC thermistor (0402) Murata NCP15WF104J03RC R1–R4 4 2.2kΩ ±5% resistors (0402) R5 1 100kΩ ±1% resistor (0402) R6, R10, R14, R17, R18 0 Not installed, resistors (0402) R7, R8 2 3.01kΩ ±1% resistors (0402) R9 1 6.04kΩ ±1% resistor (0402) R11, R12 2 604Ω ±1% resistors (0402) 1 1.21kΩ ±1% resistor (0402) 1 2.1mm male power connector CUI Inc. PJ-002A-SMT R13 1 1.25mm (0.049in) surface-mount, right-angle pitch header, lead-free, 10 circuits Molex 53261-1071 R15 1 0.56Ω ±1% resistor (0603) Panasonic ERJ-3RQJR56V 1 1-cell Li+ charger (28 TQFN-EP*) Maxim MAX8903AETI+ 5 3-pin headers Sullins PEC36SAAN Digi-Key S1012E-36-ND U1 JU1, JU2, JU3, JU8, JU9 — 10 Shunts (see Table 1) Digi-Key S900-ND or equivalent JU4–JU7, JU10, JU11 6 — 1 PCB: MAX8903A EVALUATION KIT+ J3 J4 2-pin headers Sullins PEC36SAAN Digi-Key S1012E-36-ND *EP = Exposed pad. Component Suppliers SUPPLIER PHONE WEBSITE CUI Inc. 503-612-2300 www.cui.com Digi-Key Corp. 800-344-4539 www.digikey.com Molex 800-768-6539 www.molex.com Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com Panasonic Corp. 800-344-2112 www.panasonic.com Sullins Electronics Corp. 760-744-0125 www.sullinselectronics.com Taiyo Yuden 800-348-2496 www.t-yuden.com TDK Corp. 847-803-6100 www.component.tdk.com TOKO America, Inc. 847-297-0070 www.tokoam.com Note: Indicate that you are using the MAX8903 when contacting these component suppliers. 2 _______________________________________________________________________________________ MAX8903A Evaluation Kit 7) Remove the shunt from pins 1-2 of jumper JU8 and place the shunt on pins 2-3 of jumper JU8. Recommended Equipment 8) If 3V ≤ V BAT ≤ 4.1V for MAX8903A/MAX8903B/ MAX8903C, or 3V ≤ VBAT ≤ 4.0V for MAX8903D/ MAX8903E/MAX8903Y, verify that the current from BATT into the battery is approximately 1A. • MAX8903A EV kit • Adjustable DC power supply capable of greater than 6V at 3A • Battery or simulated battery 1-cell Li+ or Li-poly battery (Figure 2A) Simulated battery—preloaded power supply (Figure 2B) • Two digital multimeters (DMM) • Up to 3A adjustable load • Three 10A ammeters 9) Increase the load current on SYS to 1A. 10) Verify that the voltage on SYS remains approximately equal to VBATT. 11) Verify that the charge current into the battery remains near 1A. 12) Increase the load current on SYS to 1.5A. 13) Verify that the voltage on SYS remains approximately equal to VBATT. Procedure 14) Verify that the charge current into the battery decreased to approximately 0.5A. The EV kit is fully assembled and tested. Follow the steps below to verify board operation. Use twisted wires of appropriate gauge that are as short as possible to connect the battery and power sources. 15) Increase the load current on SYS to 2.5A. 16) Verify that current out of the battery (from the battery to SYS) is near 0.5A. 1) Preset the DC power supply to 6V. Turn off the power supply. Caution: Do not turn on the power supply until all connections are completed. Detailed Description of Hardware Adjusting the EV Kit for In-Circuit Evaluation 2) Preset the adjustable load to 0A. 3) Connect the EV kit to the power supply, battery or preloaded power supply, adjustable load, and meters, as shown in Figure 3. Verify that the AC adapter source current limit is higher than the SYS and BAT current requirements. Note that if SYS current demand exceeds the DC-DC converter output current limit, then the battery will help supply the extra current. The DC-DC converter output current limit can also be adjusted on the MAX8903A EV kit by replacing R7 or adjusting JU4 and JU5. Verify that the USB source supplies at least 500mA. Verify the maximum charge current rating or desired charge current 4) Ensure that the EV kit has the jumper settings shown in Figure 3 and Table 1. 5) Turn on the power supply. 6) Verify that the voltage at SYS is approximately 4.4V and that the current from BATT into the battery is 0A. A. Li+\Li-POLY BATTERY B. SIMULATED BATTERY (PRELOADED POWER SUPPLY) BAT BAT MAX8903A EV KIT GND 0 TO 4.2V ≥ 2.5A 2Ω ≥ 10W MAX8903A EV KIT GND Figure 2. Battery Options for Evaluating the MAX8903A EV Kit _______________________________________________________________________________________ 3 Evaluates: MAX8903A–MAX8903E/MAX8903Y Quick Start JU11 SYS A MAX8903A EVALUATION KIT A 1 DC 2 3 JU1 BAT JU9/USUS JU8/CEN JU3/IUSB ADJUSTABLE LOAD BAT VOLTMETER BATTERY OR SIMULATED BATTERY 1 2 3 A JU10/THM GND 1 2 3 SYS VOLTMETER GND JU5 JU4 JU6 JU7 POWER SUPPLY JU2/DCM Evaluates: MAX8903A–MAX8903E/MAX8903Y MAX8903A Evaluation Kit GND *ALL AMMETERS NEED TO BE SET FOR 10A READINGS. THIS MINIMIZES THE SERIES IMPEDANCE OF THE AMMETER. Figure 3. Connection Diagram and Default Jumper Connections Table 1. Jumper Settings (JU1–JU11) DESCRIPTION JUMPER LABEL DEFAULT POSITION PINS 1-2 PINS 2-3 JU1 — Pins 2-3 shunted Use the DC pad or J2 as the DC input Use the DC pad or J3 as the DC input JU2 DCM Pins 1-2 shunted Configures DC input as adapter source (see Table 2) Configures DC input for USB power (see Table 2) JU3 IUSB Pins 1-2 shunted With DCM pins 1-2 shunted, IUSB sets 500mA USB charge current With DCM pins 2-3 shunted, IUSB sets 100mA USB charge current JU4 — Shunted JU5 — Shunted Shorts out R9 (see Table 3) JU6 — Open Shunting JU6 shorts out R12 (see Table 4) JU7 — Shunted Shorts out R13 (see Table 4) JU8 CEN Pins 1-2 shunted Disables the battery charger (when the charger is off, SYS remains on) Enables the battery charger (when the charger is on, SYS remains on) JU9 USUS Pins 2-3 USB suspend mode USB not suspended JU10 THM Shunted Connects THM to GND to bypass thermistor function JU11 — Shunted Indicator LED anodes connected to SYS 4 Shorts out R8 (see Table 3) _______________________________________________________________________________________ MAX8903A Evaluation Kit 3) When charging the battery with VBAT > VSYSMIN, the SYS voltage is regulated at the battery voltage for lowest power dissipation. When the input current limit is reached, the first action taken by the MAX8903 is to reduce battery charge current. This allows the charging current to be programmed for the fastest charge time, without dropping the SYS load at load currents that would cause the input supply regulation current to be exceeded. If, after the charge current is reduced to 0mA, the load at SYS still exceeds the input current limit, the battery helps supply power to support the system load. The MAX8903 features flexible input connections (at the DC and USB inputs) and current-limit settings (set by DCM and IUSB) to accommodate nearly any input power configuration. However, it is expected that most systems use one of two external power schemes: separate connections for USB and an AC adapter, or a single connector that accepts either USB or the AC adapter output. Input and charger current limits are shown in Table 2. Adjusting the DC-DC Converter Output Current Limit and BAT Fast-Charge Current Limit Input and charger current limits are set, as shown in Table 2. It is often preferable to change the input current limit as the input power source is changed. The MAX8903A facilitates this by allowing different input current limits for the DC and USB inputs. The SYS voltage regulates to three different regulation points depending on the state of the MAX8903: 1) If CEN is high to disable the charger, or charging is done, the SYS voltage regulates to 4.4V. 2) When charging the battery with VBAT < VSYSMIN, the SYS voltage regulates to VSYSMIN + 0.2V and stays above VSYSMIN during transient loads. Table 2. Input Limiter Control Logic POWER SOURCE AC Adapter at DC Input DOK UOK DCM IUSB USUS DC STEP-DOWN OUTPUT CURRENT LIMIT L X H X X 6000/RIDC L X L L L 100mA L X L H L 500mA L X L X H USB suspend USB INPUT CURRENT LIMIT Lesser of 1200/RISET and 6000/RIDC USB input off. DC input has priority. USB Power at DC Input H L X L L H L X H L USB Power at USB Input, DC Unconnected DC and USB Unconnected MAXIMUM CHARGE CURRENT*** Lesser of 1200/RISET and 100mA Lesser of 1200/RISET and 500mA 0 100mA Lesser of 1200/RISET and 100mA H L X X H USB suspend Lesser of 1200/RISET and 500mA 0 H H X X X No USB input 0 No DC input 500mA ***Charge current cannot exceed the input current limit. Charge may be less than the maximum charge current if the total SYS load exceeds the input current limit. X = Don’t care. _______________________________________________________________________________________ 5 Evaluates: MAX8903A–MAX8903E/MAX8903Y rating of the battery. Ensure that the charge current setting of the EV kit does not exceed the battery rating, or replace resistor R11 (or adjust JU6 and JU7) as required. See the Adjusting the DC-DC Converter Output Current Limit and BAT Fast-Charge Current Limit section for more details. Evaluates: MAX8903A–MAX8903E/MAX8903Y MAX8903A Evaluation Kit EV Kit On-Board Current-Limit Adjustment The MAX8903’s DC-DC converter output current limit can be adjusted on the EV kit by shunting JU4, JU5, or both. See Table 3 for jumper and resistor combinations and corresponding current limits. The BAT fast-charge current limit can be adjusted by shunting JU6, JU7, or both. See Table 4 for jumper and resistor combinations and corresponding fast-charge current limits. Thermistor (THM) The EV kit comes with a thermistor preinstalled on the NTC footprint. To evaluate the MAX8903A with a battery-pack thermistor, remove the thermistor and connect to the EV kit using the THM pad. Details of thermistors are covered in the MAX8903 IC data sheet. To disable the thermistor function, shunt jumper JU10. Charge Timers A fault timer prevents the battery from charging indefinitely. The fault prequalification and fast-charge timers are controlled by the capacitance at CT (C5). t PREQUAL = 33 min × C5 0. 15μF (tPREQUAL is when VBATT < 3V). t FST -CHG = 660 min × C5 0. 15μF t TOP -OFF = 15s (MAX8903 A / C / D / Y ) t TOP -OFF = 132min × While in fast-charge mode, a large system load or device self-heating could cause the MAX8903 to reduce charge current. Under these circumstances, the fast-charge timer is slowed by 2x if the charge current drops below 50% of the programmed fast-charge level, and suspended if the charge current drops below 20% of the programmed level. The fast-charge timer is not affected at any current if the charger is regulating the BAT voltage at 4.2V (i.e., the charger is in voltage mode). Indicator LEDs Indicator LEDs are provided for CHG, FLT, DOK, and UOK. The CHG LED (D3) is on when the battery charger is in its prequalification and fast-charge states. The FLT LED (D2) is on when the battery charger has entered a fault state after the charge timer expires. The DOK LED (D1) is on when 4.15V < VDC < 16V. The UOK LED (D4) is on when the source at USB is 4.1V < VUSB < 6.6V. Refer to the MAX8903 IC data sheet for more details regarding CHG, FLT, DOK, and UOK. Charge Enable (CEN) When CEN is low, the charger is on. When CEN is high, the charger turns off. CEN does not affect the SYS output, which remains on. In many systems, there is no need for the system controller (typically a microprocessor) to disable the charger, because the MAX8903 Smart Power Selector™ circuitry independently manages charging and adapter/battery power hand-off. In these situations, CEN may be connected to ground. C CT (MAX8903 B/ E) 0. 15μF Table 3. DC-DC Converter Output Current Limit (JU4, JU5) JUMPER JU5 RESISTORS FROM IDC TO GND RESISTANCE FROM IDC TO GND () SYS CURRENT LIMIT (A) Open Open R7 + R8 + R9 12k 0.5 Open Shunt R7 + R8 6k 1 Shunt Open R7 + R9 9k 0.66 Shunt Shunt R7 3k 2 RESISTANCE FROM IDC TO GND () BAT FAST-CHARGE CURRENT LIMIT (A) 0.5 JU4 Table 4. BAT Fast-Charge Current Limit (JU6, JU7) JUMPER JU7 RESISTORS FROM IDC TO GND Open Open R11 + R12 + R13 2.4k Open Shunt R11 + R12 1.2k 1 Shunt Open R11 + R13 1.8k 0.66 Shunt Shunt R11 604 2 JU6 Smart Power Selector is a trademark of Maxim Integrated Products, Inc. 6 _______________________________________________________________________________________ MAX8903A Evaluation Kit Evaluates: MAX8903A–MAX8903E/MAX8903Y DC DC 1 J2 2 2 3 3 JU1 LX 28 27 GND L1 1μH C1 2.2μF R15 0.56Ω 1% 5 J3 LX C10 4.7μF 4 1 3 2 3 DC 4 DC 1 1 PG 2 PG DC TP3 1 2 3 VL JU2 5 C7 0.1μF LX JU3 7 R1 2.2kΩ 1% LED DCM 8 D1 9 C5 0.1μF R10 OPEN D3 DOK 21 BAT 20 BAT R7 3.01kΩ 1% UOK R12 604Ω 1% VL 1 2 3 JU9 R4 2.2kΩ LED 1% 19 FLT 11 R2 2.2kΩ LED 1% IDC GND FLT 18 D2 TP2 USB R11 604Ω 1% 13 1 USB 17 JU8 14 15 2 3 C2 4.7μF GND J1 4 VL ISET VL 1 2 3 J4-10 J4-9 J4-8 J4-7 J4-6 J4-5 J4-4 J4-3 J4-2 J4-1 GND CT R18 OPEN R13 1.21kΩ 1% J4 C3A 10μF D4 12 JU6 BATT VL UOK R8 3.01kΩ 1% R14 OPEN JU7 22 TP1 JU4 R9 6.04kΩ 1% C9 OPEN R3 2.2kΩ LED 1% IUSB R17 OPEN JU5 GND THM 10 C8 OPEN C4 10μF MAX8903A VL C6 2.2μF SYS CHG BST CHG DOK JU11 24 SYS 23 SYS U1 6 1 2 3 LED 26 CS 25 CS CEN THM R5 100kΩ 1% 16 NTC USUS JU10 R6 OPEN THM THM C11 OPEN EP Figure 4. MAX8903A EV Kit Schematic _______________________________________________________________________________________ 7 Evaluates: MAX8903A–MAX8903E/MAX8903Y MAX8903A Evaluation Kit Figure 5. MAX8903A EV Kit Component Placement Guide—Top Layer 8 _______________________________________________________________________________________ MAX8903A Evaluation Kit Evaluates: MAX8903A–MAX8903E/MAX8903Y Figure 6. MAX8903A EV Kit PCB Layout—Top Layer _______________________________________________________________________________________ 9 Evaluates: MAX8903A–MAX8903E/MAX8903Y MAX8903A Evaluation Kit Figure 7. MAX8903A EV Kit PCB Layout—Inner Layer 2 10 ______________________________________________________________________________________ MAX8903A Evaluation Kit Evaluates: MAX8903A–MAX8903E/MAX8903Y Figure 8. MAX8903A EV Kit PCB Layout—Inner Layer 3 ______________________________________________________________________________________ 11 Evaluates: MAX8903A–MAX8903E/MAX8903Y MAX8903A Evaluation Kit Figure 9. MAX8903A EV Kit PCB Layout—Bottom Layer 12 ______________________________________________________________________________________ MAX8903A Evaluation Kit PAGES CHANGED REVISION NUMBER REVISION DATE 0 1/09 Initial release 1 8/09 Added MAX8903C and MAX8903D to parts evaluated 1–12 2 10/10 Added MAX8903B, MAX8903E, and MAX8903Y to parts evaluated 1–12 DESCRIPTION — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13 © 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. Evaluates: MAX8903A–MAX8903E/MAX8903Y Revision History