19-4410; Rev 4; 5/11 KIT ATION EVALU E L B A AVAIL 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power The MAX8903A–MAX8903E/MAX8903G/MAX8903H/ MAX8903J/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 on-chip. 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 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* MAX8903YETI+T -40°C to +85°C 28 Thin QFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. **Future product—contact factory for availability. T = Tape and reel. Typical Operating Circuit AC ADAPTER OR USB LX SYS DC 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 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/Y General Description MAX8903A–E/G/H/J/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 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 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 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 MAX8903A/MAX8903B/MAX8903E/ MAX8903G/MAX8903Y 3.0 MAX8903C/MAX8903D/MAX8903H/ MAX8903J 3.4 MAX8903A/MAX8903C/ MAX8903D/MAX8903H/MAX8903Y Regulation Voltage ISYS = 0A Load Regulation ISYS = 0 to 2A MAX8903B/MAX8903E/ MAX8903G V 4.3 4.4 4.5 4.265 4.325 4.395 MAX8903J 4.5 MAX8903A/MAX8903C/ MAX8903D/MAX8903H 40 V mV/A CS to SYS Resistance MAX8903B/MAX8903E/ MAX8903G/MAX8903J/MAX8903Y 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 25 _______________________________________________________________________________________ 3 MAX8903A–E/G/H/J/Y ELECTRICAL CHARACTERISTICS (continued) MAX8903A–E/G/H/J/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 TA = +25°C 4.179 4.200 4.221 TA = -40°C to +85°C 4.158 4.200 4.242 UNITS BATTERY CHARGER MAX8903A/ MAX8903B/ MAX8903C/ MAX8903G/ MAX8903H BAT Regulation Voltage (VBATREG) IBAT = 0mA MAX8903D/ MAX8903E MAX8903J MAX8903Y Charger Restart Threshold BAT Prequal Threshold (VBATPQ) Prequal Charge Current Fast-Charge Current DONE Threshold (ITERM) 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 Change in VBAT from DONE to fast-charge -150 -100 -60 MAX8903A/MAX8903C/MAX8903D/ MAX8903H/MAX8903J/MAX8903Y 2.9 3.0 3.1 MAX8903B/MAX8903E/MAX8903G 2.4 2.5 2.6 RISET = 600Ω 1800 2000 2200 RISET = 1.2kΩ (MAX8903A/MAX8903C/MAX8903D) 900 1000 1100 RISET = 2.4kΩ 450 500 550 VBAT rising 180mV hystersis Percentage of fast-charge current set at ISET 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 CCT = 0.15µF 33 min Fast-Charge Time CCT = 0.15µF 660 min Top-Off Timer (tTOP-OFF) MAX8903A/MAX8903C/MAX8903D/MAX8903H/ MAX8903J/MAX8903Y (fixed) 15 s Charger Thermal Limit Gain CHARGER TIMER Prequalification Time MAX8903B/MAX8903E/MAX8903G, 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 _______________________________________________________________________________________ 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 THM Input Leakage MAX8903A/MAX8903C/ MAX8903D/MAX8903H/ MAX8903J/MAX8903Y MAX8903B/MAX8903E/ MAX8903G 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 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/MAX8903C/ MAX8903D/MAX8903H/ MAX8903J/MAX8903Y) VINPUT = 0V to 5.5V (MAX8903B/MAX8903E/ MAX8903G) 50 TA = +25°C -1.000 TA = +85°C TA = -40°C to +85°C ±0.001 +1.000 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 ±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/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 VDC = VUSB = 6V VL UVLO Threshold MIN TYP MAX IVL = 0 to 1mA (MAX8903A/MAX8903C/ MAX8903D/MAX8903H/ MAX8903J/MAX8903Y) 4.6 5.0 5.4 IVL = 0 to 10mA (MAX8903B/MAX8903E/ MAX8903G) 4.6 UNITS V 5.0 VVL falling; 200mV hysteresis 5.4 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.) BATTERY CHARGER EFFICIENCY vs. BATTERY VOLTAGE EFFICIENCY (%) 70 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 1.5 2.0 2.5 3.0 3.5 4.0 BATTERY VOLTAGE (V) 4.5 5.0 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 4.0 0.5 10 0 6 VDC = 6V 80 4.5 MAX8903A toc02 VDC = 5V 90 SWITCHING FREQUENCY (MHz) 80 100 MAX8903A toc01a 90 SWITCHING FREQUENCY vs. VDC MAX8903G BATTERY CHARGER EFFICIENCY vs. BATTERY VOLTAGE MAX8903A toc01 100 EFFICIENCY (%) MAX8903A–E/G/H/J/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 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 10 10 100 10000 1000 1 10 100 SYS OUTPUT CURRENT (mA) USB SUPPLY CURRENT vs. USB VOLTAGE USB SUPPLY CURRENT vs. USB VOLTAGE (SUSPEND) BATTERY LEAKAGE CURRENT vs. BATTERY VOLTAGE 0.6 CHARGER DISABLED 0.4 100 80 60 40 20 0.2 MAX8903A toc06 120 80 BATTERY LEAKAGE CURRENT (nA) 0.8 140 MAX8903A toc05 MAX8903A toc04 1.0 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 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 60 50 40 30 20 350 300 VIUSB = VUSB 250 200 VIUSB = 0V 150 100 10 NO DC OR USB INPUT -15 10 35 TEMPERATURE (°C) 60 85 800 6 CHARGER ENABLED IBAT SET TO 1A IDC SET TO 2A MAX8903A/MAX8903C VBAT RISING 600 400 200 50 0 0 1000 CHARGE CURRENT (mA) 400 CHARGE CURRENT (mA) 70 CHARGE ENABLED IBAT SET TO 1.5A MAX8903D VBAT RISING 450 1200 MAX8903A toc08 500 MAX8903A toc07 80 -40 1 USB VOLTAGE (V) 90 BATTERY LEAKAGE CURRENT (nA) 0 0 0 10,000 1000 SYS OUTPUT CURRENT (mA) CHARGER ENABLED 1.2 VDC = 16V 50 DC VOLTAGE (V) 1.6 1.4 60 0 1 16 USB QUIESCENT CURRENT (µA) 4 70 20 VDC = 4.5V 0 0 USB SUPPLY CURRENT (mA) 60 80 MAX8903A toc09 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 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/Y Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) MAX8903A/C BATTERY REGULATION VOLTAGE vs. AMBIENT TEMPERATURE 1.005 1.000 0.995 0.990 0.985 -15 -40 10 35 60 100.3 4.0 100.1 100.0 99.9 VUSB FALLING 3.0 2.5 2.0 1.5 99.7 1.0 VUSB RISING 0.5 99.6 22ppm/°C -40 -15 10 35 0 85 60 RSYS = 1MΩ 0 99.5 1 2 3 4 5 6 7 USB VOLTAGE (V) MAX8903A/MAX8903C/MAX8903D SYS VOLTAGE vs. DC VOLTAGE SYS VOLTAGE vs. SYS OUTPUT CURRENT SYS VOLTAGE vs. SYS OUTPUT CURRENT, USB INPUT 4.40 SYS VOLTAGE (V) 3.5 VDC RISING 2.5 2.0 VDC FALLING 1.5 VCEN = 5V VBAT = 0V VUSB = 0V 0.5 4.38 MAX8903B/MAX8903E VDC = 5.75V 4.20 4.10 USB AND DC UNCONNECTED VBATT = 4V 6 8 10 12 14 16 4.35 4.34 MAX8903B/MAX8903E 4.31 4.30 0 18 0.5 1.0 1.5 2.0 0 100 SYS OUTPUT CURRENT (A) DC VOLTAGE (V) 5 VBAT (V) 4 3 2 1 0 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 2 4 6 8 10 12 DC VOLTAGE (V) 14 16 400 18 1.2 1.0 0.8 0.6 2.5 2.0 1.5 1.0 0.5 IBAT 0.4 0.2 MAX8903A/MAX8903B/MAX8903C 0 0 300 CHARGE PROFILE—1400mAh BATTERY ADAPTER INPUT—1A CHARGE MAX8903A toc16 6 200 SYS OUTPUT CURRENT (mA) VL VOLTAGE vs. DC VOLTAGE VL VOLTAGE (V) 4.36 4.32 3.80 4 4.37 4.33 3.90 0 2 MAX8903A/MAX8903C/ MAX8903D 4.39 4.30 4.00 1.0 VUSB = 5V 4.40 0 20 40 60 80 100 TIME (min) _______________________________________________________________________________________ 0.0 120 140 IBAT (A) 3.0 4.41 SYS VOLTAGE (V) 4.0 MAX8903A/MAX8903C/MAX8903D VDC = 5.75V MAX8903A toc14 MAX8903A toc13 4.50 MAX8903A toc15 TEMPERATURE (°C) 4.5 0 3.5 99.8 85 VCEN = 5V VBAT = 0V VDC = 0V 4.5 100.2 MAX8903A toc12 100.4 TEMPERATURE (°C) 5.0 8 5.0 SYS VOLTAGE (V) 1.010 SYS VOLTAGE vs. USB VOLTAGE 100.5 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/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/D/E/H/J/Y DC SWITCHING WAVEFORMS—LIGHT LOAD CHARGE PROFILE—1400mAh BATTERY USB INPUT—500mA CHARGE MAX8903A toc18 5.0 4.5 0.450 4.0 0.400 20mV/div AC-COUPLED VOUT VBAT 3.0 0.300 2.5 0.250 IBAT 2.0 0.200 1.5 0.150 1.0 MAX8903A/MAX8903B/MAX8903C IUSB SET TO 500mA IBAT SET TO 2A 0.5 0 0 IBAT (A) 0.350 3.5 VBAT (V) MAX8903A toc19 0.500 0.100 5V/div VLX 0V ILX 0.050 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/Y DC SWITCHING WAVEFORMS—HEAVY LOAD MAX8903G DC SWITCHING WAVEFORMS—LIGHT LOAD MAX8903A toc20 MAX8903A toc19a 50mV/div AC-COUPLED VSYS VDC = 9V, L = 2.2µH CSYS = 22µF, RSYS = 44I VLX 10V/div 20mV/div AC-COUPLED VOUT 5V/div 0V VLX 0V 1A/div ILX 0A ILX 500mA/div RSYS = 5Ω 0A 1µs/div 200ns/div MAX8903G DC SWITCHING WAVEFORMS—HEAVY LOAD DC CONNECT WITH USB CONNECTED (RSYS = 25Ω) MAX8903A toc21 MAX8903A toc20a 3.6V VSYS VDC = 9V, L = 2.2µH CSYS = 22µF, RSYS = 5I CEN = 1 50mV/div AC-COUPLED IDC 10V/div VLX 0V 2V/div VSYS IUSB 347mA 475mA 500mA/div 500mA/div -IBAT = CHARGING IBAT ILX 0A 500mA/div -335mA 1A/div 0A 1µs/div 200µs/div _______________________________________________________________________________________ 9 MAX8903A–E/G/H/J/Y Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) MAX8903A–E/G/H/J/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 3.68V 3.6V VSYS 3.6V VBAT 5V/div 1A/div IDC 0A -IBAT = CHARGING IBAT 144mA BATTERY CHARGER SOFT-START 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 3.6V 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 -1A MAX8903A/C/D/H/Y SYS LOAD TRANSIENT ISYS 1A/div 0A 850mA 400µs/div VSYS 2V/div 3.75V 3.5V 2V/div 5V 5V/div VUSB CUSB CHARGING 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 USB RESUME MAX8903A toc27 VUSUS IUSB 0V 475mA 3V MAX8903A toc28 5V/div 0A VUSUS 500mA/div IUSB 0V 3V 500mA/div VSYS IBAT -330mA 144mA 100µs/div 2V/div 3.7V 500mA/div IBAT -475mA 0A 3.6V VSYS IBAT 500mA/div 475mA 0A 475mA IUSB 5V/div CUSB CHARGING 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/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/Y Pin Description (continued) PIN NAME FUNCTION 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 a 10µF (MAX8903A/MAX8903C/MAX8903D/MAX8903H/MAX8903J/MAX8903Y) or 22µF (MAX8903B/MAX8903E/MAX8903G/MAX8903Y) X5R or X7R ceramic capacitor. 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 ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power AC ADAPTER DC LX BST CS MAX8903A– MAX8903E MAX8903G MAX8903Y DC POWER MANAGEMENT PWR OK Li+ BATTERY CHARGER AND SYS LOAD SWITCH PWM STEP-DOWN REGULATOR DOK MAX8903A–E/G/H/J/Y PG CHARGER CURRENTVOLTAGE CONTROL SET INPUT LIMIT SYS TO SYSTEM LOAD ISET BATTERY CONNECTOR BAT BAT+ + BAT- USB POWER MANAGEMENT USB USB PWR OK T THERMISTOR MONITOR (SEE FIGURE 7) CURRENTLIMITED VOLTAGE REGULATOR UOK IC THERMAL REGULATION NTC VL CHARGE TERMINATION AND MONITOR SET INPUT LIMIT THM CHG DC DCM FLT DC MODE USB LIMIT 500mA IUSB 100mA USB SUSPEND USUS 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/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power RPU 4 x 100kΩ TO VL 1 2 PG PG CDC 4.7µF 3 DC ADAPTER MAX8903A– MAX8903E MAX8903G MAX8903Y 4 DC 6 CBST 0.1µF FLT UOK DOK CHG BST 27 LX 18 FAULT OUTPUT 19 USB PWR OK 8 DC PWR OK 22 CHARGE INDICATOR 13 RISET 11 RIDC ISET 28 LX IDC L1 1µH 25 CS (SEE TABLE 5 FOR INDUCTOR SELECTION) 26 CS SYS 24 SYS 23 BAT 21 BAT 20 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 TO SYSTEM LOAD CSYS 10µF (MAX8903A/MAX8903C/MAX8903D/MAX8903H/MAX8903J) 22µF (MAX8903B/MAX8903E/MAX8903G/MAX8903Y) 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 TO VL 1 2 PG PG CDC 4.7µF 3 DC VBUS 4 DC D- 6 D+ CBST 0.1µF ID GND FLT UOK DOK CHG BST 27 LX 18 FAULT OUTPUT 19 USB PWR-OK 8 DC PWR-OK 22 CHARGE INDICATOR 13 RISET 11 RIDC ISET 28 LX L1 1µH 499kΩ IDC 25 CS 26 CS (SEE TABLE 5 FOR INDUCTOR VALUE SELECTION) 17 DC MODE MAX8903A– MAX8903E MAX8903G MAX8903Y USB ADAPTER 5 OFF CHARGE ON 14 500mA 100mA 7 USB SUSPEND 15 10 CCT 0.15µF USB SYS 24 SYS 23 BAT 21 BAT 20 TO SYSTEM LOAD CSYS 10µF (MAX8903A/MAX8903C/MAX8903D/MAX8903H/MAX8903J) 22µF (MAX8903B/MAX8903E/MAX8903Y) 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/Y RPU 4 x 100kΩ MAX8903A–E/G/H/J/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 3.0V in the MAX8903A/MAX8903B/MAX8903E/ MAX8903G/MAX8903Y and 3.4V for MAX8903C/ MAX8903D/MAX8903H/MAX8903J. 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 16 4MHz operation due to the minimum on-time, the controller 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 ______________________________________________________________________________________ 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. MAX8903A– MAX8903E MAX8903G MAX8903Y VSYSREG VBATREG VSYS IBAT x RON VSYSMIN VBAT VCEN = 0V VDC AND/OR VUSB = 5.0V Figure 4. SYS Tracking VBAT to the Minimum System Voltage 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. 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. USB Input When charging from the USB input, the DC input stepdown regulator turns off and a linear regulator from ______________________________________________________________________________________ 17 MAX8903A–E/G/H/J/Y 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 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/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 USB INPUT CURRENT LIMIT UOK DCM*** L X H X X 6000V/RIDC L X L L L 100mA L X L H L 500mA Lesser of 1200V/RISET and 500mA L X L X H USB suspend 0 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 IUSB USUS 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** DOK 100mA No DC input 500mA Lesser of 1200V/RISET and 100mA Lesser of 1200V/RISET and 100mA **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. 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. 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 out18 put. 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. 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 ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power 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. 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 maxiMONITORING THE BATTERY CHARGE CURRENT WITH VISET VISET (V) 0 0 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. 1.5 DISCHARGING mum 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. 1200V/RISET BATTERY CHARGING CURRENT (A) Figure 5. Monitoring the Battery Charge Current with the Voltage from ISET to GND 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). ______________________________________________________________________________________ 19 MAX8903A–E/G/H/J/Y again as long as the SYS load current is less than the set current limit. MAX8903A–E/G/H/J/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) ANY STATE 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 ICHG > ITERM RESET TIMER ANY CHARGING STATE THM OK TIMER RESUME TIMER > tPREQUAL 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 THM NOT OK TIMER SUSPEND TEMPERATURE SUSPEND ICHG = 0mA UOK OR DOK PREVIOUS STATE CHG = HIGH IMPEDANCE FLT = HIGH IMPEDANCE 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 VBAT < VBATPQ - 180mV RESET TIMER TOGGLE CEN OR REMOVE AND RECONNECT THE INPUT SOURCE(S) 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 tPREQUAL = 33 min × CCT 0.15µF tFST − CHG = 660 min × CCT 0.15µF t TOP − OFF = 15s (MAX8903 A/MAX8903C/MAX8903D/ MAX8903H/MAX8903J /MAX8903Y t TOP − OFF = 132 min × 20 CCT 0.15µF (MAX8903B MAX8903E MAX8903G) 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/Y CEN MAX8903A– MAX8903E MAX8903G MAX8903Y VL THERMISTOR CIRCUITRY VL 0.87 VL RTB ALTERNATE THERMISTOR CONNECTION 0.74 VL MAX8903B/MAX8903E/ MAX8903G ONLY THERMISTOR DETECTOR COLD THM RTS 0.28 VL RTP HOT RT 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) 25.14 27.15 29.32 31.66 36.91 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: RT = R25 × e ⎧ ⎛ 1 1 ⎞⎫ − ⎨β ⎜ ⎟⎬ 298°C ⎠ ⎭⎪ ⎩⎪ ⎝ T + 273°C ______________________________________________________________________________________ 21 MAX8903A–E/G/H/J/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 MAX8903A–MAX8903E/MAX8903Y THM temperature limits for different thermistor material constants. 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. 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 22 completely, and so retain the ability to remove the battery 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. Power Dissipation Table 4. Package Thermal Characteristics 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 Minimum SYS Output Capacitor The MAX8903B/MAX8903E/MAX8903G have a SYS load regulation of 25mV/A versus a load regulation of 40mV/A on the MAX8903A/MAX8903C/MAX8903D/ MAX8903Y. To achieve tighter load regulation, the loop gain on the MAX8903B/MAX8903E/MAX8903G is higher. To ensure feedback loop stability with higher gain, a larger SYS output capacitor is required (see Table 7). 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 ontime constraints (tONMIN), the regulator becomes a fixed minimum on-time valley current regulator. ______________________________________________________________________________________ 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power 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 , ⎟× VDC(MIN) ⎠ fSW ⎝ otherwise, ⎛ VSYS(MAX) ⎞ 1 tOFF = ⎜ 1 − ⎟× VDC(MIN) ⎠ fSW ⎝ where tOFF is the off-time, VSYS(MAX) is maximum charger output voltage, and VDC(MIN) is minimum DC input voltage. (2) 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 ≥ I SDLIM ≥ 1A) designs. (3) LOUT _ MIN _ TOFF = VSYS(MAX) × tOFF K × ISDLIM (4) LOUT _ MIN _ t = ON ( 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 , V f ⎝ DC(MAX) SW ⎠ ⎝ 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). (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/Y 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. MAX8903A–E/G/H/J/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power 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/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/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/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/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 MAX8903A–E/G/H/J/Y Table 5. Recommended Inductor Examples (continued) 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 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/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 MAX8903Y Minimum SYS Regulation Voltage (VSYSMIN) 3.0V 3.0V 3.4V 3.4V 3.0V 3.0V 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 Minimum Allowable Inductor 2.2µH 2.2µH 2.2µH 2.2µH 2.2µH 2.2µH 1µH 1µH 1µH Switching Frequency 4MHz 4MHz 4MHz 4MHz 4MHz 1MHz 4MHz 4MHz 4MHz SYS Load 40mV/A 25mV/A 40mV/A 40mV/A 25mV/A 25mV/A 40mV/A 25mV/A 25mV/A Minimum SYS Output Capacitor 10µF 22µF 10µF 10µF 22µF 22µF 10µF 10µF 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 BAT Prequal Threshold (VBATPQ) (Note 5) 3V 2.5V 3V 3V 2.5V 2.5V 3V 3V 3V Top-Off Timer (Note 6) 15s (fixed) 132min 15s (fixed) 15s (fixed) 132min 132min 15s (fixed) 15s (fixed) 15s (fixed) 1mA 10mA 1mA 1mA 10mA 10mA 1mA 1mA 1mA Power-Enable On Battery Detection (Note 7) No Yes No No Yes Yes No No No Comments — — — — — — (Note 8) — — VL Output Note 5: Note 6: Note 7: Note 8: 26 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 12 GND 11 IDC CS 26 10 CT LX 27 9 VL 8 DOK SYS 24 MAX8903_ CS 25 3 4 5 6 7 DC DCM BST IUSB 2 DC 1 PG + PG LX 28 EP TQFN 4mm x 4mm ______________________________________________________________________________________ 27 MAX8903A–E/G/H/J/Y Pin Configuration MAX8903A–E/G/H/J/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 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. ______________________________________________________________________________________ 29 MAX8903A–E/G/H/J/Y Package Information (continued) MAX8903A–E/G/H/J/Y 2A 1-Cell Li+ DC-DC Chargers for USB and Adapter Power Revision History REVISION NUMBER REVISION DATE 0 12/08 Initial release 1 8/09 Added MAX8903C/MAX8903D to data sheet 2 11/09 Made various corrections 3 10/10 Added MAX8903B, MAX8903E, MAX8903G, and MAX8903Y 1–29 4 5/11 Added MAX8903H and MAX8903J and updated components 1–29 DESCRIPTION PAGES CHANGED — 1–20 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. 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.