1 Features
1• Fuel gauge and battery diagnostics for flow meter
applications predict end-of-service or early battery
failure
– Supports lithium thionyl chloride (Li-SOCl2)
and lithium manganese dioxide (Li-MnO2)
chemistry batteries
– Accurate voltage, temperature, current, and
coulomb counter measurements that report
battery health and service life
– State-of-health (SOH) algorithm for Li-MnO2
– End-of-service (EOS algorithm for Li-SOCl2)
– Coulomb accumulation (ACC) algorithm for all
battery types
• Ultra-low average power consumption to
maximize battery run time
– Gauge enabled through host-controlled
periodic updates
– State-of-health (SOH) ~0.06 μA
– End-of-service (EOS) ~0.35 μA
– Coulomb accumulation (ACC) diagnostic
updates ~0.3 μA
• System interaction capabilities
– I2C host communication, providing battery
parameter and status access
– Configurable host interrupt
– Battery information data logging options for in
operation diagnostics and failure analysis
– SHA-1 authentication to help prevent
counterfeit battery use

2 Applications
• Used in primary battery systems and suitable for
dynamic load and large ambient temperature
change applications
– Smart meters and flow meters
– Door access control
– Smoke and gas leak detectors
– Building automation
– IoT, including sensor nodes
– Asset tracking
• Battery status reporting and diagnostics with early
failure detection for flow meter systems
• Extends battery runtime with accurate battery
gauging for smoke detector, sensor node, and
asset tracker applications

3 Description
The BQ35100 Battery Fuel Gauge and End-Of-
Service Monitor provides highly configurable fuel
gauging for non-rechargeable (primary) lithium
batteries without requiring a forced discharge of the
battery. Built so that optimization is not necessary to
achieve accurate gauging, the BQ35100 device uses
patented TI gauging algorithms to support the option
to seamlessly replace an old battery with a new one.
The BQ35100 device provides accurate results with
ultra-low average power consumption where less
than 2 μA can be achieved through host control via
the GAUGE ENABLE (GE) pin. The device is only
required to be powered long enough, at a systemdetermined
update frequency, to gather data and to
make calculations to support the selected algorithm.
A typical system may need to only be updated once
every 8 hours as the gauge is not required to be
powered to measure all discharge activity.
The fuel gauging functions use voltage, current, and
temperature measurements to provide state-of-health
(SOH) data and end-of-service (EOS) warning
information where the host can read the gathered
data through a 400-kHz I2C bus. An ALERT output,
based on a variety of configurable status and data
options, is also available to interrupt the host.