Decrease Voltage Drop - Quectel RM500Q-AE Manual

2, 4, 70, 72, 74
3, 5, 11, 27, 33, 39, 45, 51, 57,
71, 73
3.3.1.3.4.1.

Decrease Voltage Drop

The power supply range of the module is from 3.135 V to 4.4 V. Please ensure that the input voltage will
never drop below 3.135 V, otherwise the module will be powered off automatically. The following figure
shows the maximum voltage drop during radio transmission in 3G/4G/5G networks.
Figure 3: Power Supply Limits during Radio Transmission
The main power supply from an external system must be a single voltage source. To decrease voltage
drop, a bypass capacitor of about 100 µF with low ESR (ESR = 0.7 Ω) should be used, and a multi-layer
ceramic chip capacitor (MLCC) array also should be used due to its ultra-low ESR. It is recommended to
use four ceramic capacitors (1 µF, 100 nF, 33 pF, 10 pF) for composing the MLCC array, and place these
capacitors close to VCC pins. The width of VCC trace should be no less than 2 mm. In principle, the
longer the VCC trace is, the wider it should be.
In addition, to guarantee stability of the power supply, please use a zener diode with a reverse zener
voltage of 5.1 V and a dissipation power of higher than 0.5 W. The following figure shows a reference
circuit of VCC.
RM500Q-AE&RM502Q-AE_Hardware_Design
VCC PI
GND
RM500Q-AE&RM502Q-AE Hardware Design
3.135–4.4 V 3.7 V typical DC supply
Ground
5G Module Series
27 / 83