Product Info

LTE Standard Module Series
EC25 Series Hardware Design
EC25_Series_Hardware_Design 41 / 126
diode with suggested low reverse stand-off voltage V
RWM
4.5 V, low clamping voltage V
C
and high reverse
peak pulse current I
PP
should be used. The following figure shows the star structure of the power supply.
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Figure 7: Star Structure of the Power Supply
3.6.3. Reference Design for Power Supply
Power design for the module is very important, as the performance of the module largely depends on the
power source. The power supply should be able to provide sufficient current up to 2.0 A at least. If the
voltage drop between the input and output is not too high, it is suggested that an LDO should be used to
supply power for the module. If there is a big voltage difference between the input source and the desired
output (VBAT), a buck converter is preferred to be used as the power supply.
The following figure shows a reference design for +5.0 V input power source. The typical output of the
power supply is about 3.8 V and the maximum load current is 3.0 A.
DC_IN
MIC29302WU
IN OUT
EN
GND
ADJ
2 4
1
3
5
VBAT
100K
47K
470R
51K
1%
1%
4.7K
47K
VBAT_EN
470 μF
470 μF
100 nF
100 nF
Figure 8: Reference Circuit of Power Supply
In order to avoid damaging internal flash, please do not switch off the power supply when the module
works normally. Only after the module is shut down by PWRKEY or AT command, then the power supply
can be cut off.
3.6.4. 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].
NOTE