EVALUATION KIT AVAILABLE Click here for production status of specific part numbers. MAX745 Switch-Mode Lithium-Ion Battery-Charger General Description Features The MAX745 provides all functions necessary for charging Charges 1 to 4 Li+ Battery Cells lithium-ion (Li+) battery packs. It provides a regulated 0.75% Voltage-Regulation Accuracy charging current of up to 4A without getting hot, and a Using 1% Resistors regulated voltage with only 0.75% total error at the battery Provides up to 4A without Excessive Heating terminals. It uses low-cost, 1% resistors to set the output 90% Efficient voltage, and a low-cost N-channel MOSFET as the power switch. Uses Low-Cost Set Resistors and N-Channel Switch The MAX745 regulates the voltage set point and charging Up to 24V Input current using two loops that work together to transition Up to 18V Maximum Battery Voltage smoothly between voltage and current regulation. The 300kHz Pulse-Width Modulated (PWM) Operation per-cell battery voltage regulation limit is set between 4V and 4.4V using standard 1% resistors, and then the number Low-Noise, Small Components of cells is set from 1 to 4 by pin-strapping. Total output Stand-Alone OperationNo Microcontroller Needed voltage error is less than 0.75%. For a similar device with an SMBus microcontroller Ordering Information interface and the ability to charge NiCd and NiMH cells, PART TEMP RANGE PIN-PACKAGE refer to the MAX1647 and MAX1648. For a low-cost Li+ charger using a linear-regulator control scheme, refer to MAX745C/D 0C to +70C Dice* the MAX846A. MAX745EAP -40C to +85C 20 SSOP Applications *Dice are tested at T = +25C. A Li+ Battery Packs Desktop Cradle Chargers Pin Configuration appears at end of data sheet. Cellular Phones Notebook Computers Hand-Held Instruments Typical Operating Circuit V IN (UP TO 24V) DCIN VL BST CELL CELL0 COUNT N DHI CELL1 SELECT ON LX OFF THM/SHDN MAX745 REF N DLO I CHARGE SETI CS VADJ R SENSE SET PER STATUS CELL VOLTAGE BATT WITH 1% RESISTORS CCV CCI GND IBAT PGND VOUT 14 Li+ CELLS (UP TO 18V) SMBus is a trademark of Intel Corp. 19-1182 Rev 4 6/19MAX745 Switch-Mode Lithium-Ion Battery-Charger Absolute Maximum Ratings DCIN to GND ...........................................................-0.3V to 26V BATT, CS to GND ....................................................-0.3V to 20V BST, DHI to GND ....................................................-0.3V to 30V PGND to GND ........................................................-0.3V to 0.3V BST to LX ..................................................................-0.3V to 6V VL Current ..........................................................................50mA DHI to LX ......................................... (LX - 0.3V) to (BST + 0.3V) Continuous Power Dissipation (T = +70C) A LX to GND .............................................. -0.3V to (DCIN + 0.3V) SSOP (derate 8.00mW/C above +70C) ...................640mW VL to GND .................................................................-0.3V to 6V Operating Temperature Range ........................... -40C to +85C CELL0, CELL1, IBAT, STATUS, CCI, CCV, REF, SETI, Storage Temperature ........................................ -60C to +150C VADJ, DLO, THM/SHDN to GND ............-0.3V to (VL + 0.3V) Lead Temperature (soldering, 10s) .................................+300C 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 (V = 18V, V = 8.4V, T = 0C to +85C. Typical values are at T = +25C, unless otherwise noted.) DCIN BATT A A PARAMETER CONDITIONS MIN TYP MAX UNITS SUPPLY AND REFERENCE DCIN Input Voltage Range 6 24 V DCIN Quiescent Supply Current 6.0V < V < 24V, logic inputs = VL 4 6 mA DCIN VL Output Voltage 6.0V < V < 24V, no load 5.15 5.40 5.65 V DCIN T = +25C 4.17 4.2 4.23 A REF Output Voltage V 6.0V < V < 24V 4.16 4.2 4.24 DCIN REF Output Load Regulation 0 < I < 1mA 10 20 mV/mA REF SWITCHING REGULATOR Oscillator Frequency 270 300 330 kHz DHI Maximum Duty Cycle 89 93 % DHI On-Resistance Output high or low 4 7 DLO On-Resistance Output high or low 6 14 VL < 3.2V, V = 12V 5 BATT BATT Input Current A VL > 5.15V, V = 12V 500 BATT VL < 3.2V, V = 12V 5 CS CS Input Current A VL > 5.15V, V = 12V 400 CS BATT, CS Input Voltage Range 4V < V < 16V 0 19 V BATT CS to BATT Offset Voltage (Note 1) 1.5 mV SETI = V (full scale) 170 185 205 CS to BATT REF mV Current-Sense Voltage SETI = 400mV 14 18 22 Not including VADJ resistor tolerance -0.65 +0.65 Absolute Voltage Accuracy % With 1% tolerance VADJ resistors -0.75 +0.75 Maxim Integrated 2 www.maximintegrated.com