●The bq2040 Gas Gauge IC With SMBus Interface is intended for battery-pack or in-system installation to maintain an accurate record of available battery charge. The bq2040 directly supports capacity monitoring for NiCd, NiMH, and Li-Ion battery chemistries.

●The bq2040 uses the System Management Bus v1.0 (SMBus) protocol and supports the Smart Battery Data (SBData) commands. The bq2040 also supports the SBData charge control functions. Battery state-of-charge, remaining capacity, remaining time, and chemistry are available over the serial link. Battery-charge state can be directly indicated using a four-segment LED display to graphically depict battery full-to-empty in 25% increments.

●The bq2040 estimates battery self-discharge based on an internal timer and temperature sensor and user-programmable rate information stored in external EEPROM. The bq2040 also automatically recalibrates or \x93learns\x94 battery capacity in the full course of a discharge cycle from full to empty.

●The bq2040 may operate directly from three nickel chemistry cells. With the REF output and an external transistor, a simple, inexpensive regulator can be built to provide VCC for other battery cell configurations.

●An external EEPROM is used to program initial values into the bq2040 and is necessary for proper operation.

● Provides accurate measurement of available charge in NiCd, NiMH, and Li-Ion batteries

● Supports SBS v1.0 data set and two-wire interface

● Monitors charge FET in Li-Ion pack protection circuit

● Designed for battery pack integration

●\- Low operating current

●\- Complete circuit can fit on less than 3/4 square inch of PCB space

● Supports SBS charge control commands for NiCd, NiMH, and Li-Ion

● Drives a four-segment LED display for remaining capacity indication

● 16-pin narrow SOIC