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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
Vendor
Part number
Power(watts)
Packages
1
On semi
MMSZ5231BT1G
500mW
SOD123
2
Prisemi
PZ3D4V2H
500mW
SOD323
3
Vishay
MMSZ4689-V
500mW
SOD123
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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