1FEATURES
2• Next Generation Patented Impedance Track™
Technology Accurately Measures Available
Charge in Li-Ion and Li-Polymer Batteries
– Better Than 1% Error Over the Lifetime of
the Battery
• Supports the Smart Battery Specification
SBS V1.1
• Flexible Configuration for 2 to 4 Series Li-Ion
and Li-Polymer Cells
• Powerful 8-Bit RISC CPU With Ultralow Power
Modes
• Full Array of Programmable Protection
Features
– Voltage, Current, and Temperature
• Satisfies JEITA Guidelines
• Added Flexibility to Handle More Complex
Charging Profiles
• Lifetime Data Logging
• Supports SHA-1 Authentication
• Available in a 20-Pin TSSOP (PW) package

APPLICATIONS
• Notebook PCs
• Medical and Test Equipment
• Portable Instrumentation

DESCRIPTION
The bq20z40 SBS-compliant gas gauge and
protection IC, incorporating patented Impedance
Track™ technology, is designed for battery-pack or
in-system installation. The bq20z40 measures and
maintains an accurate record of available charge in
Li-ion or Li-polymer batteries using its integrated
high-performance analog peripherals. The bq20z40
monitors capacity change, battery impedance,
open-circuit voltage, and other critical parameters of
the battery pack, and reports the information to the
system host controller over a serial-communication
bus. It is designed to work with the bq29330 analog
front-end (AFE) protection IC to maximizes
functionality and safety while minimizing external
component count and cost in smart battery circuits.
The Impedance Track™ technology continuously
analyzes the battery impedance, resulting in superior gas-gauging accuracy. This enables the remaining
capacity to be calculated with discharge rate,
temperature, and cell aging that are all accounted for
during each stage of every cycle.