MAX1679 19-1545 Rev 0 9/99 Single-Cell Li+ Battery Charger for Current-Limited Supply General Description Features The MAX1679 battery charger for a single lithium-ion (Li+) Simple Stand-Alone Application Circuit cell comes in a space-saving 8-pin MAX package. This Lowest Power Dissipation simple device, in conjunction with a current-limited wall 8-Pin MAX Package Saves Space cube and a PMOS transistor, allows safe and fast charg- ing of a single Li+ cell. No Inductor Required The MAX1679 initiates charging in one of three ways: 0.75% Overall System Accuracy battery insertion, charger power-up, or external manip- Continuous Voltage and Temperature Protection ulation of the THERM pin. Charging terminates when the average charging current falls to approximately 1% Safely Precharges Near-Dead Cells of the fast-charge current, or when the on-chip counter Programmable Safety Timeout times out. Top-Off Charging to Achieve Full Battery Capacity Key safety features include continuous voltage and temperature monitoring, a programmable charger time- Automatic Power-Down when Power Source is out, and a 5mA precharge current mode to charge Removed near-dead cells. Automatic detection of input power removal shuts down the device, minimizing current drain from the battery. An overall system accuracy of 0.75% ensures that the cell capacity is fully utilized without cycle life degradation. The MAX1679 evaluation kit (MAX1679EVKIT) is avail- Ordering Information able to help reduce design time. PART TEMP. RANGE PIN-PACKAGE MAX1679EUA -40C to +85C 8 MAX Applications Single-Cell Li+ Portable Applications Self-Charging Battery Packs PDAs Cell Phones Typical Operating Circuit Cradle Chargers CURRENT- LIMITED PFET VOLTAGE Pin Configuration SOURCE LED GATE IN TOP VIEW CHG BATT BATTERY MAX1679 IN 1 8 BATT TIMER RANGE TSEL GND GATE 2 7 THERM SELECT MAX1679 CHG 3 6 GND THERM ADJ TSEL 4 5 ADJ THERMISTOR MAX Maxim Integrated Products 1 For free samples & the latest literature: Single-Cell Li+ Battery Charger for Current-Limited Supply ABSOLUTE MAXIMUM RATINGS Continuous Power Dissipation (T = +70C) IN, CHG, GATE to GND ........................................ -0.3V to +26V A BATT, TSEL, THERM, ADJ to GND ........................ -0.3V to +6V 8-Pin MAX (derate 4.1mW/C above +70C) ........... 330mW Operating Temperature Range ...........................-40C to +85C GATE to IN................................................................-6V to +0.3V THERM, ADJ to BATT...............................................-6V to +0.3V Storage Temperature Range ............................ -65C to +150C Lead Temperature (soldering, 10sec) ............................ +300C GATE Continuous Current ................................................ -10mA 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 = V = +10V, V = +4.2V, TSEL = GND, GATE = unconnected, ADJ = unconnected, THERM = 10k to GND, T = 0C IN CHG BATT A to +85C, unless otherwise noted. Typical values are at T = +25C.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Voltage (Note 1) V External PMOS FET off 522 V IN Input Voltage for Removable V External PMOS FET off 622 V IN Battery (Note 1) Undervoltage Lockout Trip Point V rising 2.1 2.2 2.3 V BATT Undervoltage Lockout Trip-Point V falling 60 mV BATT Hysteresis Fast-Charge Qualification V rising, transition from precharge to full BATT 2.425 2.500 2.575 V Threshold current V falling, transition from DONE to BATT Fast-Charge Restart Threshold 3.783 3.89 4.00 V PREQUAL state (Figure 2) Precharge Source Current V = 2V 45 6 mA BATT BATT Regulation Voltage 4.1685 4.2000 4.2315 V BATT Regulation Adjust Range 4.0 4.2 V ADJ Source Impedance 9.8 10 10.2 k ADJ Output Voltage No load on ADJ 1.393 1.400 1.407 V Battery Removal Detection V rising 4.875 5.0 5.125 V BATT Threshold % Battery Removal Detection V falling 125 mV BATT Threshold Hysteresis BATT Input Current (Note 2) V V -0.3V 0.1 1 A IN BATT BATT Input Current, Fast- I V = 4V 900 1500 A BATT BATT Charge State BATT Input Current, Done State I V = 4.25V 500 1000 A BATT BATT IN Input Current, Fast-Charge I V = 4V, V = 4V 30 100 A IN BATT IN State IN Input Current, Done State I V = 4.25V, V = 22V 250 600 A IN BATT IN Timer Accuracy See Table 3 -10 +10 % CHG Output Leakage Current V = 22V, CHG = high -1 +1 A CHG 2 MAX1679