Reference Design For Power Supply - Quectel SC600Y-EM Series Hardware Design

To decrease voltage drop, a bypass capacitor of about 100µF with low ESR (ESR=0.7Ω) should be used,
and a multi-layer ceramic chip capacitor (MLCC) array should also be reserved due to its ultra-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/VDD_RF/VPH_PWR pins. The width of VBAT trace should be
no less than 3mm. 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 0.5W TVS and place it as close
to the VBAT pins as possible to increase voltage surge withstand capability. The following figure shows
the structure of the power supply.
VBAT VPH_PWR
+
D1 C1
100uF

3.4.3. Reference Design for Power Supply

The power design for the module is very important, as the performance of module largely depends on the
power source. The power supply of SC600Y&SC600T should be able to provide sufficient current up to
3A at least. By default, it is recommended to use a battery to supply power for SC600Y&SC600T. But if
battery is not intended to be used, it is recommended to use a regulator for SC600Y&SC600T. If the
voltage difference between the input and output is not too high, it is suggested to use an LDO 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 +5V input power source which adopts an LDO
(MIC29502WU) from MICROCHIP. The typical output voltage is 3.8V and the maximum rated current is
5.0A.
SC600Y&SC600T_Hardware_Design
+
C5
C4 C6
C2 C3
100nF 33pF 10pF NM 100nF 33pF
Figure 4: Star Structure of Power Supply
SC600Y&SC600T Hardware Design
+
C9
C7 C8
C10 C11 C12
10pF
100nF 33pF 10pF
NM
Smart LTE Module Series
VDD_RF
VPH_PWR
VBAT
Module
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