BQ27520-G4 Datasheet, PDF (25/34 Pages) Texas Instruments – System-Side Impedance Track Fuel Gauge

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bq27520-G4
SLUSB20B – NOVEMBER 2012 – REVISED DECEMBER 2015
9.2.2.6 REGIN Power Supply Input Filtering
A ceramic capacitor is placed at the input to the fuel gauge internal LDO to increase power supply rejection
(PSR) and improve effective line regulation. It ensures that voltage ripple is rejected to ground instead of
coupling into the internal supply rails of the fuel gauge.
9.2.2.7 V_CC LDO Output Filtering
A ceramic capacitor is also needed at the output of the internal LDO to provide a current reservoir for fuel gauge
load peaks during high peripheral utilization. It acts to stabilize the regulator output and reduce core voltage
ripple inside of the fuel gauge.
9.2.3 Application Curves
2.65
8.8
VREGIN = 2.7 V
VREGIN = 4.5 V
8.7
2.6
8.6
2.55
8.5
2.5
8.4
8.3
2.45
8.2
2.4
8.1
2.35
Temperature (qC)
8
-40 -20
0
20
40
60
80 100
D001
Temperature (qC)
D002
Figure 13. Regulator Output Voltage vs. Temperature
34
33.5
33
32.5
32
31.5
31
30.5
30
-40 -20
0
20
40
60
Temperature (qC)
80 100
D003
Figure 14. High-Frequency Oscillator Frequency vs.
Temperature
5
4
3
2
1
0
-1
-2
-3
-4
-5
-30 -20 -10 0 10 20 30 40 50 60
Temperature (qC)
D004
Figure 15. Low-Frequency Oscillator Frequency vs.
Temperature
Figure 16. Reported Internal Temperature Measurement
vs. Temperature
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