LPWA Module Series
BG96 Hardware Design
BG96_Hardware_Design 29 / 79
VBAT
Burst
Transmission
Min.3.3V
Ripple
Drop
Burst
Transmission
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.
Module
VBAT_RF
VBAT_BB
VBAT
C 1
100uF
C6
C7
C8
+
+
C2
100nF
C5
C3
33pF
C4
10pF
D1
TVS
100uF
100nF 33pF 10pF
Figure 5: Star Structure of the Power Supply
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]
.