19-2800; Rev 0; 4/03 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications The device achieves high flexibility by providing an adjustable fast-charge current, top-off current, safety timer, and thermal-regulation setpoint. Other features include input power detection (ACOK) and input under-/ overvoltage protection. The MAX1501 provides activelow control inputs. The MAX1501 accepts a 4.5V to 13V supply, but disables charging when the input voltage exceeds 6.5V, preventing excessive power dissipation. The MAX1501 operates over the extended temperature range (-40°C to +85°C) and is available in a compact 16-pin thermally enhanced 5mm x 5mm thin QFN package with 0.8mm profile. Features ♦ Stand-Alone or Microprocessor-Controlled (µP) Linear 1-Cell Li+ or 3-Cell NiMH/NiCd Battery Charger ♦ No FET, Reverse-Blocking Diode, or CurrentSense Resistor Required ♦ 1.4A (max) Programmable Fast-Charge Current ♦ +95°C, +115°C, and +135°C Proprietary Programmable Die Temperature Regulation Control ♦ 4.5V to 13V Input Voltage Range with Input Overvoltage (OVLO) Protection Above 6.5V ♦ Programmable Top-Off Current Threshold: 10%, 20%, or 30% of the Fast-Charge Current ♦ Charge-Current Monitor for Fuel Gauging ♦ Programmable Safety Timer (3, 4.5, or 6 hours) ♦ Input Power Detection Output (ACOK) and Charge Enable Input (CHGEN) ♦ Automatic Recharge ♦ Digital Soft-Start Limits Inrush Current ♦ Charge Status Outputs for LEDs or µP Interface Ordering Information PART MAX1501ETE TEMP RANGE PIN-PACKAGE -40°C to +85°C 16 Thin QFN Typical Operating Circuit INPUT 4.5V TO 13V 4.2V 1-CELL Li+ IN Applications 1µF BATT 10µF INP Cellular and Cordless Phones MAX1501 PDAs FULLI Digital Cameras and MP3 Players GLED VL USB Appliances RLED SELV Charging Cradles and Docks TEMP MODE Bluetooth™ Equipment TMAX CHGEN VLOGIC (≤ 5.5V) RPULLUP SETI Pin Configuration appears at end of data sheet. ACOK 2.8kΩ GND Bluetooth is a trademark of Ericsson. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX1501 General Description The MAX1501 intelligent, constant-current, constantvoltage (CCCV), temperature-regulated battery charger charges a single lithium-ion (Li+) cell or three-cell NiMH/NiCd batteries. The device integrates the currentsense resistor, PMOS pass element, and thermalregulation circuitry, while eliminating the reverseblocking Schottky diode to create the simplest charging solution for hand-held equipment. The MAX1501 functions as a stand-alone charger to control the charging sequence from the prequalification state through fast charge, top-off, and charge termination for single-cell Li+ or three-cell NiMH/NiCd batteries. Alternatively, the MAX1501 collaborates with a host microprocessor to determine the best charging algorithm. Proprietary thermal-regulation circuitry limits the die temperature when fast charging or while exposed to high ambient temperatures, allowing maximum charging current without damaging the charger. The MAX1501 continually supplies a regulated output voltage under no-battery conditions, allowing battery changing. MAX1501 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications ABSOLUTE MAXIMUM RATINGS IN, INP, RLED, GLED to GND ................................-0.3V to +14V IN to INP ................................................................-0.3V to +0.3V VL, BATT, SETI, ACOK, MODE, CHGEN, SELV, FULLI, TMAX, TEMP to GND ................................-0.3V to +6V VL to IN...................................................................-14V to +0.3V Continuous Power Dissipation (TA = +70°C) 16-Pin 5mm ✕ 5mm Thin QFN (derate 21.3mW/°C above +70°C) .............................1702mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°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 (VIN = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ, CIN = 1µF, CBATT = 10µF, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS IN, INP Input Voltage MIN TYP 0 IN, INP Input Operating Range UNITS 13 V 6.25 V 4.5V ≤ VIN ≤ 6.25V, IVL < 250µA 2.7 3 3.3 V VIN - VBATT, rising 40 70 100 ACOK Trip Point VIN - VBATT, falling 30 55 85 ACOK Sink Current 4.5V ≤ VIN ≤ 6.25V, V ACOK = 0.6V VL Output Voltage 4.50 MAX VIN - VBATT, hysteresis Undervoltage Lockout Trip Point 15 75 4.05 4.125 4.20 VIN falling 3.9 4.025 4.1 6.25 6.50 100 VIN rising Li+, NiMH/NiCd, and no-battery modes IN Input Current µA VIN rising Hysteresis Overvoltage Lockout Trip Point Disable mode Leakage into Battery 5 8 3 45 80 VIN = 0 3 10 Disable mode 2 6 Disable mode RMS Charge Current Li+ mode Battery Regulation Voltage NiMH/NiCd mode V mA 0.25 VBATT = 4.3V VIN = VINP = 13V, VBATT = 0 V mV 6.75 1.5 Off mode (VIN = 4V) BATT Input Current mV 5 µA 1.4 A SELV = VL 4.166 4.2 4.234 SELV = GND 4.067 4.1 4.133 SELV = VL, VIN = VINP = 6V 4.85 4.95 5.05 SELV = GND µA V 4.4 4.5 4.6 Output Regulation Voltage No-battery mode 3.700 4.0 4.234 V BATT Precharge Threshold Voltage BATT rising 2.675 2.8 2.925 V Fast-Charge Current-Loop System Accuracy 2 RSETI = 2.8kΩ 460 500 540 RSETI = 1.75 kΩ 736 800 864 _______________________________________________________________________________________ mA Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications (VIN = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ, CIN = 1µF, CBATT = 10µF, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Precharge Current System Accuracy Die Temperature Regulation Setpoint (Note 1) Current-Sense Amplifier Gain CONDITIONS % of fast-charge current, VBATT = 2V MIN TYP MAX UNITS 5 10 15 % TEMP = GND 95 TEMP = open 115 TEMP = VL 135 IBATT to ISETI, precharge mode, VBATT = 2V 0.70 1 1.30 IBATT to ISETI, fast-charge mode 0.95 1 1.05 Internal Current-Sense Resistance 84 Regulator Dropout Voltage VIN - VBATT, NiMH/NiCd mode, VBATT = 4.3V, IBATT = 425mA Logic Input Low Voltage CHGEN, MODE, 4.5V ≤ VIN ≤ 6.25V Logic Input High Voltage CHGEN, MODE, 4.5V ≤ VIN ≤ 6.25V 1.25 Internal Pulldown Resistance CHGEN, MODE 100 Internal Pullup Resistance SELV 100 Internal Bias Resistance FULLI, TEMP, TMAX 50 Internal Bias Voltage FULLI, TEMP, TMAX RLED Output Low Current V RLED = 1V 7 GLED Output Low Current V GLED = 1V 14 GLED, RLED Output High Leakage Current V GLED = V RLED = VIN = VINP = 13V Full-Battery Detection Current Threshold % of fast-charge current VBATT Restart Threshold Li+ mode NiMH/NiCd mode Charge-Timer Accuracy Charge-Timer Duration o 190 350 mV 0.52 V 175 400 kΩ 175 400 kΩ 90 200 kΩ 10 18 mA 20 34 mA 0.1 1 µA V VVL/2 V 5 10 15 FULLI = VL 15 20 25 FULLI = open 25 30 35 SELV = VL 3.9 4.0 4.1 3.8 3.9 4.0 3.9 4.0 4.1 -10 +10 TMAX = GND 3 TMAX = open 4.5 TMAX = VL mA/A mΩ FULLI = GND SELV = GND C % V % hrs 6 _______________________________________________________________________________________ 3 MAX1501 ELECTRICAL CHARACTERISTICS (continued) MAX1501 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications ELECTRICAL CHARACTERISTICS (VIN = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ, CIN = 1µF, CBATT = 10µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2) PARAMETER CONDITIONS IN, INP Input Voltage IN, INP Input Operating Range VL Output Voltage ACOK Trip Point ACOK Sink Current Undervoltage Lockout Trip Point BATT Input Current Leakage into Battery TYP MAX 13 V 4.50 6.25 V V 2.7 3.3 VIN - VBATT, rising 40 100 VIN - VBATT, falling 30 85 4.5V ≤ VIN ≤ 6.25V, V ACOK = 0.6V 75 4.00 4.25 VIN falling 3.90 4.15 6.25 6.75 Li+, NiMH/NiCd, and no-battery modes 8 Disable mode 3 VBATT = 4.3V 80 VIN = 0 10 Disable mode 6 Disable mode RMS Charge Current Li+ mode Battery Regulation Voltage NiMH/NiCd mode V V mA µA 5 µA 1.4 A SELV = VL 4.148 4.252 SELV = GND 4.05 4.15 SELV = VL 4.85 5.05 V 4.4 4.6 Output Regulation Voltage No-battery mode 3.700 4.234 V BATT Precharge Threshold Voltage BATT rising 2.675 2.925 V RSETI = 2.8kΩ 460 540 RSETI = 1.75kΩ 736 864 5 15 Fast-Charge Current-Loop System Accuracy Precharge Current System Accuracy Current-Sense Amplifier Gain SELV = GND mV µA VIN rising VIN = VINP = 13V, VBATT = 0 UNITS 0 4.5V ≤ VIN ≤ 6.25V, IVL < 250µA Overvoltage Lockout Trip Point IN Input Current MIN % of fast-charge current, VBATT = 2V IBATT to ISETI, precharge mode, VBATT = 2V 0.60 1.40 IBATT to ISETI, fast-charge mode 0.93 1.07 Regulator Dropout Voltage VIN - VBATT, NiMH/NiCd mode, VBATT = 4.3V, IBATT = 425mA Logic Input Low Voltage CHGEN, MODE, 4.5V < VIN < 6.25V Logic Input High Voltage CHGEN, MODE, 4.5V < VIN < 6.25V 350 0.52 1.3 mA % mA/A mV V V Internal Pulldown Resistance CHGEN, MODE 100 400 Internal Pullup Resistance SELV 100 400 kΩ Internal Bias Resistance FULLI, TEMP, TMAX 50 200 kΩ 4 _______________________________________________________________________________________ kΩ Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications (VIN = VINP = 5V, VBATT = 3.5V, ACOK = GLED = RLED = TEMP = TMAX = FULLI = open, CHGEN = MODE = GND, RSETI = 2.8kΩ, CIN = 1µF, CBATT = 10µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS RLED Output Low Current V RLED = 1V 7 18 mA GLED Output Low Current V GLED = 1V 14 34 mA GLED, RLED Output High Leakage Current V GLED = V RLED = VIN = VINP = 13V 1 µA +10 % Charge-Timer Accuracy -10 Note 1: Temperature regulation setpoint variation is typically ±9°C. Note 2: Specifications to TA = -40°C are guaranteed by design, not production tested. Typical Operating Characteristics (VIN = VINP = 5V, ACOK = RLED = GLED = TEMP = TMAX = FULLI = open, CBATT = 10µF, CIN = 1µF, TA = +25°C, unless otherwise noted.) DISABLE-MODE SUPPLY CURRENT vs. INPUT VOLTAGE 2.5 2.0 1.5 1.0 0.5 0 1.4 1.2 1.0 0.8 0.6 0.4 0.2 350 300 250 200 150 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 0 1 2 3 4 5 6 7 8 9 10 11 12 13 INPUT VOLTAGE (V) INPUT VOLTAGE (V) BATTERY VOLTAGE (V) CHARGE CURRENT vs. BATTERY VOLTAGE CHARGE CURRENT vs. INPUT VOLTAGE CHARGE CURRENT vs. INPUT-VOLTAGE HEADROOM CHARGE CURRENT (mA) 400 350 300 250 200 150 100 50 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 BATTERY VOLTAGE (V) 500 450 0 Li+ MODE, SELV = VL, RSETI = 2.7kΩ 400 350 300 250 200 150 100 50 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 INPUT VOLTAGE (V) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 600 550 CHARGE CURRENT (mA) 600 550 MAX1501 toc04 NiMH/NiCd, RSETI = 2.7kΩ, VIN = 5.5V, SELV = VL 550 500 450 MAX1501 toc03 400 50 0 0 600 CHARGE CURRENT (mA) 1.6 Li+ MODE, RSETI = 2.7kΩ, VIN = 5V, SELV = VL 500 450 500 450 NiMH/NiCd MODE, SELV = GND, RSETI = 2.7kΩ, VBATT = 4.3V 400 350 MAX1501 toc06 3.0 600 550 CHARGE CURRENT (mA) 3.5 1.8 MAX1501 toc05 SUPPLY CURRENT (mA) 4.0 2.0 CHARGE CURRENT vs. BATTERY VOLTAGE MAX1501 toc02 Li+ MODE OR NiMH/NiCd MODE, SELV = VL, IBATT = 0 4.5 DISABLE-MODE SUPPLY CURRENT (mA) 5.0 MAX1501 toc01 SUPPLY CURRENT vs. INPUT VOLTAGE 300 250 200 150 100 50 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 VIN - VBATT (V) _______________________________________________________________________________________ 5 MAX1501 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VIN = VINP = 5V, ACOK = RLED = GLED = TEMP = TMAX = FULLI = open, CBATT = 10µF, CIN = 1µF, TA = +25°C, unless otherwise noted.) BATTERY REGULATION VOLTAGE vs. TEMPERATURE 3.0 2.5 2.0 1.5 1.0 0.5 Li+ MODE 0 4.20 4.16 4.14 4.12 4.08 -15 10 35 60 TEMPERATURE (°C) CHARGE CURRENT vs. AMBIENT TEMPERATURE CHARGE CURRENT vs. AMBIENT TEMPERATURE 1000 MAX1501 toc09 900 800 CHARGE CURRENT (mA) Li+ MODE, TEMP = VL, VBATT = 3.6V, VIN = 5V, RSETI = 2.7kΩ 540 520 500 480 460 700 600 85 Li+ MODE, TEMP = VL, VBATT = 3.6V, VIN = 6V, RSETI = 1.75kΩ 500 400 300 440 200 420 100 400 0 -40 -15 10 35 60 AMBIENT TEMPERATURE (°C) 6 -40 INPUT VOLTAGE (V) 600 560 SELV = GND 4.10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 580 SELV = VL 4.18 MAX1501 toc10 OUTPUT VOLTAGE (V) 3.5 4.22 MAX1501 toc08 NO BATTERY MODE IBATT = 0 BATTERY REGULATION VOLTAGE (V) 4.0 MAX1501 toc07 OUTPUT VOLTAGE vs. INPUT VOLTAGE CHARGE CURRENT (mA) MAX1501 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications 85 -40 -15 10 35 60 AMBIENT TEMPERATURE (°C) _______________________________________________________________________________________ 85 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications PIN NAME 1 INP 2 IN 3, 13 GND Ground. Connect the exposed paddle to GND. 4 SETI Current-Sense Transconductance Amplifier Output. Connect a resistor from SETI to GND to program the maximum charge current and to monitor the actual charge current. SETI pulls to GND during shutdown. 5 VL Linear Regulator Output. Connect CHGEN, TEMP, TMAX, FULLI, and MODE to VL to program logic high. VL discharges to GND during shutdown. TMAX Maximum Charging-Time Select Input. TMAX sets the maximum charging time. Connect TMAX to GND to set the maximum charging time to 3 hours. Leave TMAX floating to set the maximum charging time to 4.5 hours. Connect TMAX to VL to set the maximum charging time to 6 hours. TMAX pulls to GND through a 50kΩ resistor in shutdown. FULLI Top-Off-Current Select Input. FULLI sets the end-of-charge threshold as a percentage of the fast-charge current. Connect FULLI to GND to set the end-of-charge threshold to 10% of the fast-charge current. Connect FULLI to VL to set the end-of-charge threshold to 20% of the fast-charge current. Leave FULLI floating to set the end-of-charge threshold to 30% of the fast-charge current. FULLI pulls to GND through a 50kΩ resistor in shutdown. 8 TEMP Die Temperature Select Input. TEMP sets the die temperature regulation point for the thermal-control loop. Connect TEMP to GND to regulate the die temperature at +95°C. Leave TEMP floating to regulate the die temperature at +115°C. Connect TEMP to VL to regulate the die temperature at +135°C. TEMP pulls to GND through a 50kΩ resistor in shutdown. 9 MODE Mode Select Input. MODE and CHGEN together control charging functions (Table 1). An internal 175kΩ pulldown resistor pulls MODE low. 10 CHGEN 11 ACOK Input Voltage Range Indicator. The open-drain ACOK output asserts low when 4.2V ≤ VIN ≤ 6.25V and VIN - VBATT ≥ 100mV. ACOK requires an external 100kΩ pullup resistor. ACOK floats in shutdown. 12 BATT Battery Connection. Connect the positive terminal of the battery to BATT. BATT draws less than 5µA during shutdown. 14 SELV Battery Voltage Selection Input. SELV sets the battery regulation voltage in Li+ and NiMH/NiCd modes (Table 2). For no-battery mode, the battery voltage defaults to 4.0V. An internal 175kΩ resistor to VL pulls SELV high. RLED Battery Charging Indicator. Connect the anode of a red LED to IN and the cathode to RLED. RLED asserts low when the input supply is present and the battery is charging, regardless of cell chemistry. RLED sinks 10mA. RLED goes high impedance in shutdown. Connect a pullup resistor to the µP’s I/O supply when interfacing with a µP logic input. GLED Full-Charge Indicator. Connect the anode of a green LED to IN and the cathode to GLED. GLED asserts low when the input supply is present and the battery has reached the top-off current threshold set by FULLI, regardless of cell chemistry. GLED sinks 20mA. GLED goes high impedance in shutdown. Connect a pullup resistor to the µP’s I/O supply when interfacing with a µP logic input. 6 7 15 16 FUNCTION High-Current Charger Input. Connect an AC adapter to INP and IN as close to the device as possible. INP provides charge current to the battery. INP draws current while the device is in shutdown mode. Low-Current Charger Input. Bypass IN to GND with a 1µF ceramic capacitor. Connect IN to INP as close to the device as possible. IN powers the internal LDO and reference. IN draws current while the device is in shutdown mode. Charge Enable Input. CHGEN and MODE together control charging functions (Table 1). An internal 175kΩ pulldown resistor pulls CHGEN low. _______________________________________________________________________________________ 7 MAX1501 Pin Description MAX1501 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications MAX1501 INP BATT VREF CS OUTPUT DRIVER AND LOGIC SETI TEMP REF TEMPERATURE SENSOR IREF IN SHUTDOWN UVLO VL CHGEN VL MODE REF SELV OVLO ON LOGIC TEMP ACOK RLED FULLI GLED OSC GND TMAX GND Figure 1. Functional Diagram 8 _______________________________________________________________________________________ Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications MAX1501 OFF ACOK = HIGH CHARGER OFF ACOK = LOW RLED = OFF GLED = OFF ACOK = (4.2V < VIN < 6.25V) AND (VIN - VBATT > 100mV) ACOK = LOW CHGEN = LOW VBATT < 2.8V CHGEN = HIGH MODE = LOW NOBATT DISABLE PREQUAL CHARGER OFF ACOK = LOW RLED = OFF GLED = OFF 10% SETI CURRENT ACOK = LOW RLED = ON GLED = OFF CHGEN = LOW SOFT-START CHGEN = HIGH MODE = HIGH (CURRENT LIMITED AND CHGEN = LOW THERMALLY PROTECTED) ACOK = LOW RLED = OFF GLED = OFF SOFT-START VBATT < 2.8V FAST CHARGE (THERMALLY PROTECTED) 100% SETI CURRENT ACOK = LOW RLED = ON GLED = OFF ICHG < ITOP-OFF TIME > TMAX VBATT < 4V (Li+ MODE, SELV = VL, AND NiMH/NiCd MODE) VBATT < 3.9V (Li+ MODE, SELV = GND) TOP OFF (VOLTAGE LOOP) RLED = OFF GLED = ON TIME > TMAX DONE CHARGER OFF RLED = OFF GLED = ON Figure 2. Charge State Diagram Detailed Description Modes of Operation CHGEN and MODE together set the operating modes of the MAX1501. Both inputs possess internal 175kΩ pulldown resistors to GND. Table 1 describes the four operating modes of the MAX1501. Table 1. Modes of Operation MODE Li+ Charge Mode CHGEN MODE 0 0 NiMH/NiCd Charge Mode 0 1 Disable Mode 1 0 No-Battery Mode 1 1 _______________________________________________________________________________________ 9 MAX1501 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications The thermal-regulation loop limits the MAX1501 die temperature to the value selected by the TEMP input by reducing the charge current as necessary (see the Thermal-Regulation Selection section). This feature not only protects the MAX1501 from overheating, but also allows the charge current to be set higher without risking damage to the system. Table 2. Battery Regulation Voltage SELV CHARGING MODE GND VL Li+ 4.1V 4.2V NiMH/NiCd 4.5V 4.95V Li+ Charge Mode Connect CHGEN and MODE to GND to place the MAX1501 in Li+ charging mode. The Li+ charger consists of a voltage-control loop, a current-control loop, and a thermal-control loop. Connect SELV to GND to set the Li+ battery voltage to 4.1V. Connect SELV to VL to set the Li+ battery voltage to 4.2V (Table 2). The MAX1501 precharges the Li+ battery with 10% of the user-programmed fast-charge current at the start of a charge cycle. A soft-start algorithm ramps up the charging current (10% steps with 20ms duration per step) to the fast-charge current when the battery voltage reaches 2.8V. The MAX1501 enters constant-voltage mode and decreases the charge current when the BATT voltage reaches the selected regulation voltage (4.1V or 4.2V). Set the fast-charge current with a resistor between SETI and GND (see the Charge-Current Selection section). REGULATION VOLTAGE PREQUALIFICATION Set the top-off-current threshold with the three-state FULLI input (see the Top-Off-Current Selection section). RLED goes high impedance and GLED asserts low when the top-off-current threshold is reached. The MAX1501 automatically initiates recharging when the battery voltage drops below 95% of the voltage set by SELV. NiMH/NiCd Charge Mode Connect CHGEN to GND and MODE to VL to place the MAX1501 in NiMH/NiCd charging mode. The NiMH/NiCd battery charger consists of a current-control loop, a voltage-control loop, and a thermal-control loop. Connect SELV to GND to set the regulation voltage to 4.5V. Connect SELV to VL to set the regulation voltage to 4.95V (Table 2). When charging three NiMH/NiCd cells to 4.95V, VIN must be at least 5.25V and a µP must be used to terminate the charge sequence. FAST CHARGING TOP-OFF DONE FAST-CHARGE CURRENT BATTERY CURRENT RLED TURNS OFF AND GLED TURNS ON WHEN CHARGE CURRENT DROPS TO VALUE SET BY FULLI (10%, 20%, OR 30% OF FASTCHARGE CURRENT). BATTERY VOLTAGE MINIMUM CHARGE VOLTAGE (2.8V) CHARGE TERMINATED 10% OF FAST-CHARGE CURRENT tPREQUAL tMAX Figure 3. Li+ Charge Sequence 10 ______________________________________________________________________________________ Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications MODE Li+ Mode or NiMH/NiCd Mode STATE • 10% current-limited precharge • Current-limited charge • Voltage-limited charge before top-off • Temperature-limited charge before top-off • Voltage-limited charge after top-off • Safety timer expires RLED GLED Sinks 10mA High impedance High impedance Sinks 20mA Disable Mode — High impedance High impedance No Battery Mode — High impedance High impedance The MAX1501 precharges the NiMH/NiCd battery with 10% of the user-programmed fast-charge current at the start of a charge cycle. Precharge ends and fast charge begins when the battery voltage exceeds 2.8V. Set the fast-charge current with a resistor between SETI and GND (see the Charge-Current Selection section). The MAX1501 enters constant-voltage mode and decreases the charge current when the battery voltage reaches 4.5V. The thermal-regulation loop limits the MAX1501 die temperature to the value selected by the TEMP input by reducing the charge current as necessary (see the Thermal-Regulation Selection section). This feature protects the MAX1501 from overheating when supplying high charge currents, or while operating from high input voltages. Set the top-off-current threshold with the three-state FULLI input (see the Top-Off-Current Selection section). RLED goes high impedance and GLED asserts low when the top-off current threshold is reached. The MAX1501 automatically initiates recharging when the battery voltage drops below 4V. No-Battery Mode Connect CHGEN and MODE to VL to place the MAX1501 in no-battery mode. An external load can be connected to BATT in this mode. VBATT regulates to 4V in no-battery mode, regardless of the state of SELV. The current-control loop, voltage-control loop, and thermal-control loop all function in no-battery mode. The loop gain of the voltage-control loop decreases to ensure stability with no battery present. Connect a 10µF ceramic capacitor to BATT for stability. RLED and GLED are both high impedance in no-battery mode. ACOK The ACOK output asserts low when VIN is present, 4.2V ≤ VIN ≤ 6.25V, and VIN - VBATT > 100mV. The ACOK open-drain output requires an external 100kΩ pullup MAX1501 Table 3. RLED and GLED Behavior resistor to an external supply voltage. The external supply voltage must be less than 5.5V. RLED and GLED Indicators RLED and GLED serve as visual indicators that power is applied as well as the charge status of a battery. RLED asserts low when a wall adapter is connected and a battery is charging, regardless of cell chemistry. GLED asserts low when power is applied and the battery is fully charged. Both outputs go high-impedance in shutdown. Connect the anode of each LED to IN, and the cathode to RLED or GLED. Table 3 summarizes the behavior of RLED and GLED under normal operating conditions. Connect pullup resistors to the µP I/O supply when interfacing RLED and GLED with a µP’s logic inputs. Soft-Start A ten-step, soft-start algorithm activates when entering fast-charge mode. The charging current ramps up in 10% increments, 20ms per step, to the full charging current when VBATT exceeds 2.8V. Applications Information Charge-Current Selection Program the charging current using an external resistor between SETI and GND. Set the charge-current resistor with the following equation: RSETI = 1000 × 1.4V IBATT If VSETI = 1.4V, the current-control loop controls the battery charging. If VSETI < 1.4V, either the voltagecontrol loop or the thermal-control loop operates. Measure the charging current by monitoring VSETI and using the following equation: I VSETI = BATT × RSETI 1000 ______________________________________________________________________________________ 11 MAX1501 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications Thermal-Regulation Selection Set the regulated die temperature of the MAX1501 with the TEMP three-level logic input. The MAX1501 reduces the charge current to limit the die temperature to the value set by TEMP. The MAX1501 operates normally while the thermal loop is active. An active thermal loop does not indicate a fault condition. TEMP allows the MAX1501 to maximize the charge current while providing protection against excessive power dissipation. Connect TEMP to GND to regulate the die temperature at +95°C. Leave TEMP floating to regulate the die temperature at +115°C. Connect TEMP to VL to regulate the die temperature at +135°C. Top-Off-Current Selection Set the top-off-current threshold in the Li+ and NiMH/NiCd charge modes with the FULLI three-level logic input. The top-off-current threshold determines when RLED turns off and GLED turns on, indicating the charge status of the battery. Connect FULLI to GND to set the top-off-current threshold to 10% of the fast-charge current. Connect FULLI to VL to set the top-off-current threshold to 20% of the fast-charge current. Leave FULLI floating to set the topoff-current threshold to 30% of the fast-charge current. Charge-Timer Selection Set the maximum charging time with the TMAX threelevel logic input. TMAX limits the duration of charging to protect the battery from overcharging. Connect TMAX to GND to set the maximum charging time to 3 hours. Leave TMAX floating to set the maximum charging time AC ADAPTER 4.5V TO 6.5V Capacitor Selection Connect a ceramic capacitor from BATT to GND for proper stability. Use a 10µF X5R ceramic capacitor for most applications. Connect IN and INP together and bypass to GND with a 1µF ceramic capacitor. Use a larger input bypass capacitor for high input voltages or high charging currents to reduce supply noise. Thermal Considerations The MAX1501 is available in a thermally enhanced thin QFN package with exposed paddle. Connect the exposed paddle of the MAX1501 to a large copper ground plane to provide a thermal contact between the device and the circuit board. The exposed paddle transfers heat away from the device, allowing the MAX1501 to charge the battery with maximum current, while minimizing the increase in die temperature. Application Circuits Figure 4 shows the MAX1501 as a stand-alone Li+ battery charger. The 2.8kΩ resistor connected to SETI sets a charging current of 500mA. Figure 5 shows the MAX1501 as a µP-based Li+ battery charger. Drive CHGEN low to charge the battery. Drive CHGEN high to disable the charger. Connect a 100kΩ pullup resistor from ACOK to the logic supply voltage of the µP to detect the presence of an input supply. The logic supply voltage must be less than 5.5V. 4.2V 1-CELL Li+ IN 1µF to 4.5 hours. Connect TMAX to VL to set the maximum charging time to 6 hours. BATT 10µF INP AC ADAPTER 4.5V TO 6.5V 4.2V 1-CELL Li+ IN 1µF BATT 10µF INP MAX1501 MAX1501 GLED MODE RLED CHGEN TMAX VI/O ACOK TEMP TEMP FULLI VL SELV ACOK µP CHGEN VL SELV SETI SETI GND GND Figure 4. Stand-Alone Li+ Battery Charger 12 TMAX RLED RPULLUP FULLI 2.8kΩ GLED 2.8kΩ MODE GND GND Figure 5. µP-Based Li+ Battery Charger ______________________________________________________________________________________ Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications 4.5V 3-CELL NiMH OR NiCd 4.75V TO 6.5V IN 1µF BATT 10µF INP 4.95V 3-CELL NiMH OR NiCd 5.25V TO 6.5V AC ADAPTER IN 1µF MAX1501 AC ADAPTER BATT 10µF INP MAX1501 MAX1501 GLED TEMP RLED ACOK TMAX FULLI SETI SELV VI/O TMAX RLED TEMP RPULLUP FULLI ACOK µP VL 2.8kΩ GLED VL CHGEN MODE SELV MODE SETI CHGEN GND GND 2.8kΩ GND GND Figure 6. Stand-Alone 3-Cell NiMH or NiCd Battery Charger Figure 7. µP-Based NiMH or NiCd Battery Charge Figure 6 shows the MAX1501 as a stand-alone NiMH/NiCd battery charger. Connecting SELV to GND sets the charge termination voltage to 4.5V. Figure 7 shows the MAX1501 as a µP-based NiMH/NiCd battery charger. Connecting SELV to VL sets the charge regulation voltage at 4.95V. Connect a 100kΩ pullup resistor from ACOK to the logic supply voltage of the µP. The logic supply voltage must be less than 5.5V. Figure 8 shows the MAX1501 as a µP-based single Li+ or 3-cell NiMH/NiCd charger. The states of MODE and CHGEN set the operating mode of the MAX1501 (Table 1). Connect a 100kΩ pullup resistor from ACOK to the logic supply voltage of the µP. The logic supply voltage must be less than 5.5V. Figure 9 shows the MAX1501 as an accurate currentlimited low-dropout linear regulator with input overvoltage protection (no-battery mode). The output voltage regulates to 4V, regardless of the state of SELV. Connect MODE to VL to enable the linear regulator. Connect MODE to GND to put the device into shutdown. RSETI sets the maximum output current. AC ADAPTER 4.1V 1-CELL Li+ OR 4.5V 3-CELL NiMH/NiCd 4.75V TO 6.5V IN 1µF BATT 10µF INP 4.5V TO 6.5V MAX1501 1µF GLED 4V IN BATT INP GLED MAX1501 RLED VI/O 100kΩ µP 2.8kΩ 10µF RLED VL VL ACOK FULLI FULLI CHGEN CHGEN TMAX TEMP MODE MODE SELV TMAX SETI TEMP ON OFF ACOK SELV SETI GND GND CURRENT-LIMIT ADJUST GND GND UP TO 1.4A Figure 8. µP-Based Single Li+/3-Cell NiMH/NiCd Battery Charger Figure 9. Input Overvoltage-Protected and Current-Limited Low-Dropout Linear Regulator ______________________________________________________________________________________ 13 MAX1501 Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications 5V 3kΩ 4.1kΩ 5.1kΩ 200kΩ 3kΩ IN 100kΩ MAX1501 CHGEN 1kΩ 5V 2.24kΩ GND 3kΩ 100kΩ RT = 10kΩ AT +25°C 10kΩ 3.66kΩ 1kΩ TBATT RT 0°C 27.28kΩ +25°C +50°C 10.00kΩ 4.16kΩ Figure 10. Battery Temperature Protection Figure 10 shows a circuit that adds temperature protection to the battery. Install the thermistor as close to the battery as possible to ensure accurate temperature measurement. The output of this circuit is logic high when the battery temperature is less than 0°C and greater than +50°C. Driving CHGEN high disables the charger. Chip Information TRANSISTOR COUNT: 5717 PROCESS: BiCMOS Layout and Bypassing RLED SELV GND Pin Configuration GLED 16 15 14 13 INP 1 12 BATT IN 2 11 ACOK GND 3 SETI 4 MAX1501 10 CHGEN **EXPOSED PADDLE 6 7 8 FULLI TEMP VL 5 9 TMAX Connect IN and INP together as close to the device as possible and bypass with a 1µF ceramic capacitor. Bypass BATT to GND with a 10µF ceramic capacitor. Provide a large copper GND plane to allow the exposed paddle to sink heat away from the device. Connect the battery to BATT as close to the device as possible to provide the most accurate battery voltage sensing. Make all high-current traces short and wide to minimize voltage drops. 5mm x 5mm THIN QFN **CONNECT EXPOSED PADDLE TO GND 14 ______________________________________________________________________________________ MODE Highly Integrated, Linear Battery Charger with Thermal Regulation for Portable Applications b CL 0.10 M C A B D2/2 D/2 PIN # 1 I.D. QFN THIN.EPS D2 0.15 C A D k 0.15 C B PIN # 1 I.D. 0.35x45 E/2 E2/2 CL (NE-1) X e E E2 k L DETAIL A e (ND-1) X e CL CL L L e e 0.10 C A C 0.08 C A1 A3 PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE 16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm APPROVAL COMMON DIMENSIONS DOCUMENT CONTROL NO. REV. 21-0140 C 1 2 EXPOSED PAD VARIATIONS NOTES: 1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994. 2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES. 3. N IS THE TOTAL NUMBER OF TERMINALS. 4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE. 5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.25 mm AND 0.30 mm FROM TERMINAL TIP. 6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY. 7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION. 8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS. 9. DRAWING CONFORMS TO JEDEC MO220. 10. WARPAGE SHALL NOT EXCEED 0.10 mm. PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE 16, 20, 28, 32L, QFN THIN, 5x5x0.8 mm APPROVAL DOCUMENT CONTROL NO. REV. 21-0140 C 2 2 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 ____________________ 15 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX1501 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)