MAX1873 19-2099 Rev 0 7/01 Simple Current-Limited Switch-Mode Li+ Charger Controller General Description Features The low-cost MAX1873R/S/T provides all functions Low-Cost and Simple Circuit needed to simply and efficiently charge 2-, 3-, or 4- Charges 2-, 3-, or 4-Series Lithium-Ion Cells series lithium-ion cells at up to 4A or more. It provides a regulated charging current and voltage with less than AC Adapter Input-Current-Limit Loop 0.75% total voltage error at the battery terminals. An Also Charges Ni-Based Batteries external P-channel MOSFET operates in a step-down DC-DC configuration to efficiently charge batteries in Analog Output Monitors Charge Current low-cost designs. 0.75% Battery-Regulation Voltage The MAX1873R/S/T regulates the battery voltage and 5A Shutdown Battery Current charging current using two control loops that work together to transition smoothly between voltage and Input Voltage Up to 28V current regulation. An additional control loop limits cur- 200mV Dropout Voltage/100% Duty Cycle rent drawn from the input source so that AC adapter size and cost can be minimized. An analog voltage out- Adjustable Charging Current put proportional to charging current is also supplied so 300kHz PWM Oscillator Reduces Noise that an ADC or microcontroller can monitor charging current. Space-Saving 16-Pin QSOP The MAX1873 may also be used as an efficient current- MAX1873 Evaluation Kit Available to Speed limited source to charge NiCd or NiMH batteries in mul- Designs tichemistry charger designs. The MAX1873R/S/T is available in a space-saving 16-pin QSOP package. Use Ordering Information the evaluation kit (MAX1873EVKIT) to help reduce design time. PART TEMP. RANGE PIN-PACKAGE Applications MAX1873REEE -40C to +85C 16 QSOP Notebook Computers MAX1873SEEE -40C to +85C 16 QSOP Portable Internet Tablets MAX1873TEEE -40C to +85C 16 QSOP 2-, 3-, or 4-cell Li+ Battery Pack Chargers Typical Operating Circuit 6-, 9-, or 10-cell Ni Battery Pack Chargers Hand-Held Instruments SYSTEM VIN 9V TO LOAD 28V Portable Desktop Assistants (PDAs) (9V MIN FOR 2- Desktop Cradle Chargers CELLS) VH VL CSSP MAX1873 Selector Guide DCIN CSSN PART SERIES CELLS TO CHARGE 4V OUT PER MAX1873REEE 2-Cell Li+ or 5- or 6-cell Ni Battery IOUT 200mV ON R CS 3-Cell Li+ or 7- or 9-cell Ni Battery EXT MAX1873SEEE ICHG/EN MAX1873TEEE 4-Cell Li+ 10-cell Ni Battery Packs REF CSB BATT CCI VADJ CCS Pin Configuration appears at end of data sheet. GND CCV 2- TO 4-CELL Li+ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLESimple Current-Limited Switch-Mode Li+ Charger Controller ABSOLUTE MAXIMUM RATINGS CSSP, CSSN, DCIN to GND...................................-0.3V to +30V VL Source Current ............................................................+50mA VL, ICHG/EN to GND................................................-0.3V to +6V VH Sink Current ................................................................+40mA VH, EXT to DCIN.......................................................-6V to +0.3V Continuous Power Dissipation (T = +70C) A VH, EXT to GND ......................................(V + 0.3V) to -0.3V 16-Pin QSOP (derate 8.3mW/C above +70C..........+667mW DCIN EXT to VH .................................................................+6V to -0.3V Operating Temperature Range DCIN to VL..............................................................+30V to -0.3V MAX1873 EEE................................................-40C to +85C VADJ, REF, CCI, CCV, CCS, Junction Temperature..................................................... +150C IOUT to GND.............................................-0.3V to (VL + 0.3V) Storage Temperature Range .............................-65C to +150C BATT, CSB to GND.................................................-0.3V to +20V Lead Temperature (soldering, 10s) ................................ +300C CSSP to CSSN.......................................................-0.3V to +0.6V CSB to BATT..........................................................-0.3V to +0.6V 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, V = V , V = V /2. MAX1873R: V = V = 8.4V DCIN CSSP CSSN ICHG/EN REF VADJ REF BATT CSB MAX1873S: V = V = 12.6V MAX1873T: V = V = 16.8V T = 0C to +85C. Typical values are at T = +25C, unless BATT CSB BATT CSB A A otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS INPUT SUPPLY AND REFERENCE DCIN Input Voltage Range 628V 6.0V < V < 28V 4 7 mA DCIN D C IN Qui escent Sup p l y Cur r ent DCIN BATT 0.1 10 A DCIN to BATT Undervoltage Threshold CSSP = DCIN, input falling 0.05 0.175 V DCIN to BATT Undervoltage Threshold CSSP = DCIN, input rising 0.22 0.38 V VL Output Voltage 6.0V < V < 28V 5.15 5.40 5.65 V DCIN VL Output Load Regulation I = 0 to 3mA 15 50 mV VL REF Output Voltage I = 21A (200k load) 4.179 4.20 4.221 V REF 26 mV REF Line Regulation 6.0V < V < 28V DCIN 22 65 ppm/V REF Load Regulation I = 0 to 1mA 6 13 mV REF SWITCHING REGULATOR PWM Oscillator Frequency 270 300 330 kHz EXT Driver Source On-Resistance 47 EXT Driver Sink On-Resistance 2.5 4.5 VH Output Voltage DCIN - VH, 6V < V <28V, I = 0 to 20mA 4.75 5.75 V DCIN VH CSSN/CSSP Input Current V /V = 28V, V = 28V 70 200 A CSSN CSSP DCIN CSSN/CSSP Off-State Leakage V = V /V = 18V, V = V = 18V 1.5 5 A DCIN SSN CSSP BATT CSB ICHG/EN = 0 (charger disabled) 0.2 1 BATT, CSB Input Current A ICHG/EN = REF (charger enabled) 250 500 BATT, CSB Input Current DCIN BATT (input power removed) 1.5 5 A 2 MAX1873