Requirements For Voltage Stability - Quectel SG560D Series Hardware Design

The following figure illustrates a reference design for +5 V input power source.
DC_IN
C1
100 nF
470 μF

3.1.4. Requirements for Voltage Stability

The recommended power supply value of the module is 4 V. The power supply performance, such as load
capacity, voltage ripple, directly influences the module's performance and stability. Under ultimate
conditions, the module may have a transient peak current of up to 5 A. If the power supply capability is not
sufficient, there will be voltage drops, and if the voltage drops below 3.2 V, the module will be turned off
automatically. Therefore, make sure the input voltage never drops below 3.2 V.
Load (A)
Power
Supply (V)
Figure 4: Power Supply Limits During Burst Transmission
To prevent the voltage from dropping below 3.2 V, it is recommended to connect a tantalum capacitor of
about 100 µF with low ESR (ESR ≤ 0.7 Ω) and reserve a multi-layer ceramic chip capacitor (MLCC) array
due to its ultra-low ESR. It is recommended to use three ceramic capacitors (100 nF, 33 pF, 10 pF) to
compose the MLCC array, and place these capacitors close to VBAT pins. Additionally, add a 4.7 µF
capacitor in parallel. The width of VBAT trace should be no less than 5 mm. In principle, the longer the
VBAT trace is, the wider it should be.
SG560D_Series_Hardware_Design
2
IN
R1
C2
51K
Figure 3: Reference Circuit of Power Supply
Burst
Transmission
U1
4
OUT
R2
220K
1%
R4
470R
R3
100K
1%
Burst
Transmission
Drop
Smart Module Series
VBAT
C3
C4
470 μF
100 nF
Ripple
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