Data Sheet

bq27441-G1
SLUSBH1C –NOVEMBER 2013–REVISED DECEMBER 2014 www.ti.com
Typical Applications (continued)
10.2.2 Detailed Design Procedure
10.2.2.1 BAT Voltage Sense Input
A ceramic capacitor at the input to the BAT pin is used to bypass AC voltage ripple to ground, greatly reducing
its influence on battery voltage measurements. It proves most effective in applications with load profiles that
exhibit high-frequency current pulses (that is, cell phones) but is recommended for use in all applications to
reduce noise on this sensitive high-impedance measurement node.
10.2.2.2 Integrated LDO Capacitor
The fuel gauge has an integrated LDO with an output on the V
DD
pin of approximately 1.8 V. A capacitor of value
at least 0.47 μF should be connected between the V
DD
pin and V
SS
. The capacitor should be placed close to the
gauge IC and have short traces to both the V
DD
pin and V
SS
.
10.2.2.3 Sense Resistor Selection
Any variation encountered in the resistance present between the SRP and SRN pins of the fuel gauge will affect
the resulting differential voltage, and derived current, it senses. As such, it is recommended to select a sense
resistor with minimal tolerance and temperature coefficient of resistance (TCR) characteristics. The standard
recommendation based on best compromise between performance and price is a 1% tolerance, 50 ppm drift
sense resistor with a 1-W power rating.
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