MAX8731 19-3923 Rev 0 1/06 SMBus Level 2 Battery Charger with Remote Sense General Description Features The MAX8731 is an SMBus programmable multichem- 0.5% Battery Voltage Accuracy istry battery charger. The MAX8731 uses a minimal 3% Input Current-Limit Accuracy command set to easily program the charge voltage, 3% Charge-Current Accuracy charge current, and adapter current limit. SMBus 2-Wire Serial Interface The MAX8731 charges one to four Li+ series cells and Cycle-by-Cycle Current Limit delivers up to 8A charge current. The MAX8731 drives Battery Short-Circuit Protection n-channel MOSFETs for improved efficiency and reduced cost. Low-offset current-sense amplifiers pro- Fast Response for Pulse Charging vide high accuracy with 10m sense resistors. Fast System-Load-Transient Response The MAX8731 current-sense amplifiers provide high Dual-Remote-Sense Inputs accuracy (3% at 3.5A) and also provide fast cycle-by- Monitor Outputs for cycle current-mode control to protect against battery Adapter Current (4% Accuracy) short circuit and system load transients. AC Adapter Detection The charger employs dual remote-sense, which reduces 11-Bit Battery Voltage Setting charge time by measuring the feedback voltage directly at the battery, improving accuracy of initial transition into 6-Bit Charge-Current/Input-Current Setting constant-voltage mode. The MAX8731 provides 0.5% 8A (max) Battery Charger Current battery voltage accuracy directly at the battery terminal. 11A (max) Input Current The MAX8731 provides a digital output that indicates the +8V to +26V Input Voltage Range presence of the AC adapter, as well as an analog output Charges Li+, NiMH, and NiCd Battery Chemistries that indicates the adapter current within 4% accuracy. The MAX8731 is available in a small 5mm x 5mm, Ordering Information 28-pin, thin (0.8mm) QFN package. An evaluation kit is available to reduce design time. The MAX8731 is avail- PART TEMP RANGE PIN-PACKAGE able in lead-free packages. MAX8731ETI+ -40C to +85C 28 Thin QFN (5mm x 5mm) SMBus is a trademark of Intel Corp. +Indicates lead-free packaging. Applications Notebook Computers Typical Operating Circuit Tablet PCs EXTERNAL LOAD Medical Devices OPTIONAL Portable Equipment with Rechargeable Batteries CSSP CSSN DHI N Pin Configuration ACIN DCIN LX ACOK TOP VIEW DLO N MAX8731 21 20 19 18 17 16 15 REF PGND BST DCIN 22 14 BATSEL CSIP CSIN GND LX 23 13 ACOK SELECTOR BATSEL 12 GND BATTERY DHI 24 FBSA A V BST 25 11 DD HOST BATSEL MAX8731 SCL SCL V 26 10 SCL CC SDA SDA BATTERY FBSB B VDD CSSN 27 9 SDA VDD *EXPOSED PADDLE 28 8 IINP CSSP LDO GND V CC 12 3 45 6 7 IINP CCV DAC CCS CCI THIN QFN 5mm x 5mm 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 AVAILABLE GND LDO ACIN DLO REF PGND CCS CSIP CCI CSIN CCV FBSB DAC FBSASMBus Level 2 Battery Charger with Remote Sense ABSOLUTE MAXIMUM RATINGS DCIN, CSSN, CSIN, FBSA, FBSB to GND..............-0.3V to +28V V , SCL, SDA, BATSEL, ACIN, ACOK, V to GND, DD CC CSSP to CSSN, CSIP to CSIN, PGND to GND ......-0.3V to +0.3V LDO to PGND......................................................-0.3V to +6V BST to GND............................................................-0.3V to +32V Continuous Power Dissipation (T = +70C) A BST to LX..................................................................-0.3V to +6V 28-Pin Thin QFN DHI to LX.................................................-0.3V to +(V + 0.3)V (derate 20.8mW/C above +70C)........................1666.7 mW BST DLO to PGND..........................................-0.3V to +(LDO + 0.3)V Operating Temperature Range ...........................-40C to +85C LX to GND .................................................................-6V to +28V Junction Temperature......................................................+150C CCI, CCS, CCV, DAC, REF, Storage Temperature Range .............................-60C to +150C IINP to GND...........................................-0.3V to (V + 0.3)V Lead Temperature (soldering, 10s) .................................+300C VCC 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 = V = V = 19V, V - V = 4.5V, V = V = V = V = 16.8V, BATSEL = GND = PGND = 0, DCIN LX CSSP CSSN BST LX FBSA FBSB CSIP CSIN C = 1F, V = LDO, C = 1F, C = 0.1F, V = 3.3V, ACIN = 2.5V pins CCI, CCV, and CCS are compensated per LDO CC REF DAC DD Figure 1 T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) A A PARAMETER CONDITIONS MIN TYP MAX UNITS CHARGE-VOLTAGE REGULATION 16.716 16.8 16.884 V ChargingVoltage() = 0x41A0 -0.5 +0.5 % 12.491 12.592 12.693 V ChargingVoltage() = 0x3130 -0.8 +0.8 % Battery Full-Charge Voltage and Accuracy 8.333 8.4 8.467 V ChargingVoltage() = 0x20D0 -0.8 +0.8 % 4.15 4.192 4.234 V ChargingVoltage() = 0x1060 -1.0 +1.0 % Battery Undervoltage-Lockout 2.5 V Trip Point for Trickle Charge CHARGE-CURRENT REGULATION CSIP to CSIN Full-Scale Current- 78.22 80.64 83.06 mV Sense Voltage 7.822 8.064 8.306 A RS2 (Figure 1) = 10m ChargingCurrent() = 0x1f80 -3 +3 % 3.809 3.968 4.126 A RS2 (Figure 1) = 10m Charge Current and Accuracy ChargingCurrent() = 0x0f80 -4 +4 % RS2 (Figure 1) = 10m 64 400 mA ChargingCurrent() = 0x0080 (128mA) Charge-Current Gain Error Based on ChargeCurrent() = 128mA and 8.064A -2 +2 % FBSA/FBSB/CSIP/CSIN 0 19 V Input Voltage Range 2 MAX8731