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SIM800L(MT6261)_Hardware Design_V1.01 20 2016-07-07
4. Application Interface
4.1. Power Supply
The power supply range of SIM800L is from 3.4V to 4.4V.Recommended voltage is 4.0V.The transmitting burst
will cause voltage drop and the power supply must be able to provide sufficient current up to 2A. For the VBAT
input, a bypass capacitor (low ESR) such as a 100 uF is strongly recommended.
Increase the 33pF and 10pF capacitors can effectively eliminate the high frequency interference. A
5.1V/500mW Zener diode is strongly recommended, the diode can prevent chip from damaging by the voltage
surge. These capacitors and Zener diode should be placed as close as possible to SIM800L VBAT pins.
VBAT
5.1V
500mW
C
A
C
B
33pF
10pF
Figure 5: Reference circuit of the VBAT input
Table 6: Recommended zener diode
2 Prisemi PZ3D4V2H 500mW SOD323
4 Crownpo CDZ55C5V1SM 500mW 0805
The following figure is the reference design of +5V input power supply. The designed output for the power
supply is 4.1V, thus a linear regulator can be used.
Vin
Vout
GND
FB
3
+
PWR_CTRL
R102
R101
VBAT
100K
43K
+
C103
330uF
C104
100nF
U101
MIC29302
5
4
1
2
C101 C102
100uF
1uF
DC INPUT
R103
470R
On/Off
Figure 6: Reference circuit of the LDO power supply
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