EVALUATION KIT AVAILABLE MAX1737 Stand-Alone Switch-Mode Lithium-Ion Battery-Charger Controller General Description Features The MAX1737 is a switch-mode lithium-ion (Li+) battery Stand-Alone Charger for Up to Four Li+ Cells charger that charges one to four cells. It provides a 0.8% Accurate Battery Regulation Voltage regulated charging current and a regulated voltage with Low Dropout: 98% Duty Cycle only a 0.8% total voltage error at the battery terminals. The external N-channel switch and synchronous rectifier Safely Precharges Near-Dead Cells provide high efficiency over a wide input voltage range. Continuous Voltage and Temperature Monitoring A built-in safety timer automatically terminates charging <1A Shutdown Battery Current once the adjustable time limit has been reached. Input Voltage Up to +28V The MAX1737 regulates the voltage set point and charging Safety Timer Prevents Overcharging current using two loops that work together to transition smoothly between voltage and current regulation. An Input Current Limiting additional control loop monitors the total current drawn Space-Saving 28-Pin QSOP from the input source to prevent overload of the input supply, 300kHz PWM Oscillator Reduces Noise allowing the use of a low-cost wall adapter. 90% Conversion Efficiency The per-cell battery voltage regulation limit is set between +4.0V and +4.4V and can be set from one to four by pin Ordering Information strapping. Battery temperature is monitored by an external thermistor to prevent charging if the battery temperature PART TEMP. RANGE PIN-PACKAGE is outside the acceptable range. MAX1737EEI -40C to +85C 28 QSOP The MAX1737 is available in a space-saving 28-pin QSOP package. Use the evaluation kit (MAX1737EVKIT) Typical Operating Circuit to help reduce design time. INPUT SUPPLY Applications DCIN CSSP VL SYSTEM CSSN Notebook Computers Li+ Battery Packs LOAD DHI Hand-Held Instruments Desktop Cradle Chargers MAX1737 LX REF Pin Configuration BST ISETIN VLO ISETOUT TOP VIEW CELL VL 1 28 DCIN DLO VADJ ISETIN 2 27 CSSP PGND ISETOUT 3 26 CSSN THM 4 25 DHI CS MAX1737 REF 5 24 LX R S GND 6 23 BST CCS BATT BATT 7 22 VLO Li+ VADJ 8 21 DLO BATTERY CCV THM 1 TO 4 CCV 9 20 PGND CELLS CCI FASTCHG CCS 10 19 CS TIMER1 FULLCHG CCI 11 18 SHDN TIMER2 FAULT CELL 12 17 FULLCHG TIMER1 13 16 FASTCHG ON SHDN OFF TIMER2 14 15 FAULT GND QSOP 19-1626 Rev 5 7/17MAX1737 Stand-Alone Switch-Mode Lithium-Ion Battery-Charger Controller Absolute Maximum Ratings CSSP, CSSN, DCIN to GND .................................-0.3V to +30V BATT, CS to GND ..................................................-0.3V to +20V BST, DHI to GND ..................................................-0.3V to +36V PGND to GND, CSSP to CSSN ...........................-0.3V to +0.3V BST to LX ................................................................-0.3V to +6V VL to VLO .............................................................-0.3V to +0.3V DHI to LX ........................................-0.3V to ((BST - LX) + 0.3V) VL Source Current............................................................50mA LX to GND ............................................. -0.3V to (CSSN + 0.3V) Continuous Power Dissipation (T = +70C) A FULLCHG, FASTCHG, FAULT to GND ................-0.3V to +30V 28-Pin QSOP (derate 10.8mW/C above +70C) .......860mW VL, VLO, SHDN, CELL, TIMER1, TIMER2, CCI, Operating Temperature Range ........................... -40C to +85C CCS, CCV, REF, ISETIN, ISETOUT, VADJ, Junction Temperature ......................................................+150C THM to GND ........................................................-0.3V to +6V Storage Temperature Range ............................ -65C to +150C DLO to GND .............................................-0.3V to (VLO + 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 (Circuit of Figure 1, V = V = V = +18V, SHDN = VL, CELL = GND, V = V = +4.2V, V = V / 2, ISETIN = DCIN CSSN CSSP BATT CS VADJ REF ISETOUT = REF, R = 10k, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) THM A A PARAMETER CONDITIONS MIN TYP MAX UNITS SUPPLY AND REFERENCE DCIN Input Voltage Range 6 28 V DCIN Quiescent Supply Current 6.0V < V < 28V 5 7 mA DCIN DCIN to BATT Undervoltage Threshold, 0.05 0.155 V DCIN Falling DCIN to BATT Undervoltage Threshold, 0.19 0.40 V DCIN Rising VL Output Voltage 6.0V < V < 28V 5.10 5.40 5.70 V DCIN VL Output Load Regulation I = 0 to 15mA 44 65 mV VL REF Output Voltage 4.179 4.20 4.221 V REF Line Regulation 6V < V < 28V 2 6 mV DCIN REF Load Regulation I = 0 to 1mA 6 14 mV REF SWITCHING REGULATOR PWM Oscillator Frequency V = 15V, CELL = VL 270 300 330 kHz BATT In dropout f / 4, V = 2.4V, OSC CCV LX Maximum Duty Cycle 97 98 % V = 15V, CELL = VL BATT CSSN + CSSP Off-State Leakage V = V = V = 28V, SHDN = GND 2 10 A CSSN CSSP DCIN DHI, DLO On-Resistance 7 LX Leakage LX = V = 28V, SHDN = GND 0.1 10 A DCIN SHDN = GND, V = 19V 0.1 5 A BATT BATT, CS Input Current CELL = SHDN = VL, V = 17V 225 500 BATT BATT, CS Input Voltage Range 0 19 V Battery Regulation Voltage (V ) CELL = float, GND, VL, or REF (Note 1) 4.167 4.2 4.233 V/cell BATTR Not including VADJ resistor tolerances -0.8 +0.8 Absolute Voltage Accuracy % With 1% VADJ resistors -1 +1 V = GND 3.948 3.979 4.010 VADJ Battery Regulation Voltage Adjustment V = 2V V/cell CCV Range V = REF 4.386 4.421 4.453 VADJ Maxim Integrated 2 www.maximintegrated.com