Reference Design For Power Supply - Quectel M12 Hardware Design

M12 Hardware Design

3.3.3. Reference design for power supply

The power design for the module is very important, since the performance of power supply for the
module largely depends on the power source. The power supply is capable of providing the
sufficient current up to 2A at least. If the voltage drop between the input and output is not too high,
it is suggested to use a LDO as module's power supply. If there is a big voltage difference between
the input source and the desired output (VBAT), a switcher power converter is preferred to use as
a power supply.
The following figure shows a reference design for +5V input power source. The designed output
for the power supply is 4.16V and the maximum load current is 3A. In addition, in order to get a
stable output voltage, a zener diode is placed close to the pins of VBAT. As to the zener diode, it is
suggested to use a zener diode which reverse zener voltage is 5.1V and dissipation power is more
than 1 Watt.
DC_IN
C1
470uF 100nF
M12_Hardware_Design_V3.3
VBAT
+
C1
100uF
GND
Figure 4 : Reference circuit for the VBAT input
MIC29302WU U1
2 IN
C2
Figure 5 : Reference circuit for power supply
C3 C4
C2
100nF 10pF 33pF
0603 0603
OUT 4
R1
120K
R2
51K
VBAT
C3 C4
D1
5.1V
470uF 100nF
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