EVALUATION KIT AVAILABLE Stand-Alone, Switch-Mode MAX1757 Li+ Battery Charger with Internal 14V Switch General Description Benefits and Features The MAX1757 is a switch-mode lithium-ion (Li+) battery Stand-Alone Charger Safely Charges Up to Three Li+ charger that charges one to three cells. It provides a Batteries regulated charging current accurate to 10% and a Continuous Voltage and Temperature Monitoring regulated voltage with only a 0.8% total voltage error Input Current Limiting at the battery terminals. The internal high-side switch 0.8% Battery Regulation Voltage Accuracy delivers a programmable current of up to 1.5A to Up to 1.5A Programmable Charge Current charge the battery. The built-in safety timer automati- cally terminates charging once the adjustable time limit Low Power Consumption Extends Battery Life has been reached. 0.1 A Shutdown Battery Current The MAX1757 regulates the voltage set point and Low-Dropout 98% Duty Cycle charging current using two loops that work together to Flexible Input Voltage Range Enables the Use of Low transition smoothly between voltage and current regula- Cost Wall Adapters tion. An additional control loop monitors the total cur- Input Voltage Up to 14V rent drawn from the input source (charging + system) and by automatically reducing battery-charging current Precharges Near-Dead Cells prevents overload of the input supply, allowing the use Fixed 300kHz PWM Oscillator Allows Effective Noise of a low-cost wall adapter. Filtering The per-cell battery regulation voltage is set between 28-Pin SSOP Package Saves Board Space 4.0V and 4.4V using standard 1% resistors. The number of cells is set from 1 to 3 by pin strapping. Battery tem- perature is monitored by an external thermistor to prevent Ordering Information charging outside the acceptable temperature range. PART TEMP. RANGE PIN-PACKAGE The MAX1757 is available in a space-saving 28-pin SSOP package. Use the MAX1757EVKIT to help MAX1757EAI -40C to +85C 28 SSOP reduce design time. For a stand-alone charger with a 28V switch, refer to the MAX1758 data sheet. For a charger controller capable of up to 4A charging cur- Typical Operating Circuit rent, refer to the MAX1737 data sheet. VIN Applications 6V to 14V DCIN CSSP Li+ Battery Packs PDAs SYSTEM CSSN LOAD Notebook Computers Desktop Cradle Chargers REF HSD Hand-Held Instruments MAX1757 LX ISETOUT BST Pin Configuration VL TOP VIEW ISETIN PGND VL 1 28 DCIN CELL CS ISETTIN 2 27 CSSP VADJ ISETOUT 3 26 CSSN BATT THM 4 25 CCV THM REF 5 24 CCI MAX1757 CCS Li+ BATTERY GND 6 23 CCS THERM 1 TO 3 CELLS VADJ 7 22 BST CCI BATT 8 21 CS HSD 9 20 LX CCV FASTCHG HSD 10 19 LX CELL 11 18 PGND TIMER1 FULLCHG TIMER1 12 17 SHDN TIMER2 FAULT TIMER2 13 16 FULLCHG ON OFF SHDN FAULT 14 15 FASTCHG GND SSOP 19-1754 Rev 2 5/15Stand-Alone, Switch-Mode MAX1757 Li+ Battery Charger with Internal 14V Switch Absolute Maximum Ratings BATT, CS, DCIN, CSSP, CSSN, HSD to GND........-0.3V to +15V PGND to GND .......................................................-0.3V to +0.3V CSSP to CSSN.......................................................-0.6V to +0.6V VL Source Current...............................................................50mA BST to GND............................................................-0.3V to +21V Continuous Power Dissipation (T = +70C) A BST to LX..................................................................-0.3V to +6V 28-Pin SSOP (derate 9.5mW/C above +70C) ...........762mW LX to PGND ..............................................-0.6V to (V + 0.3V) Operating Temperature Range ...........................-40C to +85C HSD VL, SHDN, ISETIN, ISETOUT, REF, VADJ, CELL, TIMER1, Junction Temperature......................................................+150C TIMER2, CCI, CCS, CCV, THM to GND ................-0.3V to +6V Storage Temperature Range .............................-65C to +150C FASTCHG, FULLCHG, FAULT to GND ..................-0.3V to +30V Lead Temperature (soldering, 10s) .................................+300C CS to BATT Current ............................................................3.5A 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 = V = 12V, V = V , V = GND, V = V = 4.2V, V = V /2, DCIN HSD CSSP CSSN SHDN VL CELL BATT CS VADJ REF V = V = V , R = 10k, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) ISETIN ISETOUT REF THM A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SUPPLY AND REFERENCE DCIN Input Voltage Range 614 V DCIN Quiescent Supply Current 6V < V < 14V 57 mA DCIN DCIN to BATT Dropout Falling edge 0.075 0.125 0.175 V Threshold, DCIN Falling DCIN to BATT Dropout Rising edge 0.20 0.30 0.40 V Threshold, DCIN Rising VL Output Voltage 6V < V < 14V 5.10 5.40 5.70 V DCIN VL Output Load Regulation I = 0 to 15mA 44 65 mV VL REF Output Voltage V 6V < V < 14V 4.179 4.20 4.221 V REF DCIN REF Line Regulation 6V < V < 14V 26 mV DCIN REF Load Regulation I = 0 to 1mA 614 mV REF SWITCHING REGULATOR PWM Oscillator Frequency f Nondropout f 270 300 330 kHz OSC OSC LX Maximum Duty Cycle In dropout, f / 4 97 98 % OSC CSSN/CSSP Off-State Leakage V = V = V = 14V, V = GND 210 A CSSN CSSP DCIN SHDN V = PGND, V = V = 14V, LX HSD DCIN HSD Off-State Leakage 0.1 10 A V = GND SHDN LX Off-State Leakage V = V = V =14V, V = GND 0.1 10 A LX HSD DCIN SHDN HSD to LX On-Resistance V = V + 4.5V 150 250 m BST LX LX to PGND On-Resistance See PWM Controller section 12 CS to BATT Current-Sensing Internal resistor between CS and BATT, R 110 170 m CS Resistance 1.5A RMS operating V = GND, V =14V 0.1 5 A SHDN BATT BATT, CS Input Current CELL = REF, V = 12V, any charging state 280 540 A BATT V = 14V, done state 150 270 A BATT www.maximintegrated.com Maxim Integrated 2