Monitor The Power Supply - Quectel BG96 Manual

VBAT
Min.3.3V
Figure 4: Power Supply Limits during Burst Transmission
To decrease voltage drop, a bypass capacitor of about 100µF with low ESR should be used, and a
multi-layer ceramic chip capacitor (MLCC) array should also be reserved due to its low ESR. It is
recommended to use three ceramic capacitors (100nF, 33pF, 10pF) for composing the MLCC array, and
place these capacitors close to VBAT pins. The main power supply from an external application has to be
a single voltage source and can be expanded to two sub paths with star structure. The width of VBAT_BB
trace should be no less than 0.5mm, and the width of VBAT_RF trace should be no less than 2mm. In
principle, the longer the VBAT trace is, the wider it will be.
In addition, in order to get a stable power source, it is suggested to use a TVS with low leakage current
and suitable reverse stand-off voltage, and also it is recommended to place it as close to the VBAT pins
as possible. The following figure shows the star structure of the power supply.
VBAT
D1
TVS

3.5.3. Monitor the Power Supply

AT+CBC command can be used to monitor the VBAT_BB voltage value. For more details, please refer to
document [2].
BG96_Hardware_Design
Burst
Transmission
+
C4
C2 C3
C 1
100nF 10pF
100uF 33pF
Figure 5: Star Structure of the Power Supply
Burst
Transmission
Drop
+
C5
C6 C7 C8
100uF 100nF 33pF 10pF
LPWA Module Series
BG96 Hardware Design
Ripple
VBAT_RF
VBAT_BB
Module
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