LTC1760

` Complete SMBus Charger/Selector for Two Smart Batteries
` Voltage and Current Accuracy within 0.2% of Value Reported by Battery
` Simplifies Construction of "Smart Battery System Manager"
` Includes All SMBus Charger V1.1 Safety Features
` Supports Autonomous Operation without a Host
` SMBus Switching for Dual Batteries while Maintaining Alarm Monitoring for Charging Battery at All Times
` Pin Programmable Limits for Maximum Charge Current and Voltage Improve Safety
` Allows Both Batteries to Discharge Simultaneously into Single Load with Low Loss (FET Diode)
` Fast Autonomous Power Path Switching (<10ms)
` Low Loss Simultaneous Charging of Two Batteries
` >95% Efficient Synchronous Buck Charger
` AC Adapter Current Limiting* Maximizes Charge Rate

· Portable Computers and Instruments
· Standalone Dual Smart Battery Chargers
· Battery Backup Systems

Voltage from DCIN, SCP, SCN, CLP,
V_PLUS, SW to GND.......................................... 32V/0.3 V
Voltage from SCH1, SCH2 to GND .................. 28V/0.3 V
Voltage from BOOST to GND .......................... 37V/ 0.3V
CSP, CSN, BAT1, BAT2 to GND ......................... 28V/0.3V
LOPWR, DCDIV to GND ................................... 10V/ 0.3V
Voltage from V_CC2, V_DDS to GND ...................... 7V/0.3 V
SDA1, SDA2, SDA, SCL1, SCL2, SCL, SMBALERT
to GND ................................................................ 7V/0.3V
MODE to GND .........................................V_CC2 +0.3V/0.3V
COMP1 to GND ................................................... 5V/ 0.3V
Operating Ambient Temperature (Note 6) .... 0°C to 70°C
Operating Junction Temperature ............40°C to 125°C
Storage Temperature .............................65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................... 300°C

The LTC^®1760 Smart Battery System Manager is a highly integrated level 3 battery charger and selector intended for products using dual smart batteries. Three SMBus interfaces allow the LTC1760 to servo to the internal voltage and currents measured by the batteries while allowing an SMBus Host to monitor either battery's status. Charging accuracy is determined by the battery's internal voltage and current measurement, typically better than ±0.2%.

A proprietary PowerPath^TMarchitecture supports simultaneous charging or discharging of both batteries. Typical battery run times are extended by up to 10%, while charging times are reduced by up to 50%. The LTC1760 automatically switches between power sources in less than 10ms to prevent power interruption upon battery or wall adapter removal.

The LTC1760 implements all elements of a version 1.1 "Smart Battery System Manager" except for the generation of composite battery information. An internal multiplexer cleanly switches the SMBus Host to either of the two attached Smart Batteries without generating partial messages to batteries or SMBus Host. Thermistors on both batteries are automatically monitored for temperature and disconnection information (SafetySignal).