LTE Module Series
EC25-V User Manual
EC25-V_User_Manual
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Table 6: VBAT and GND Pins
Pin Name
Pin No.
Description
Min.
Typ.
Max.
Unit
VBAT_RF
57, 58
Power supply for module RF
part.
3.3
3.8
4.3
V
VBAT_BB
59, 60
Power supply for module
baseband part.
3.3
3.8
4.3
V
GND
8, 9, 19, 22, 36,
46, 48, 50~54,
56, 72, 85~112
Ground.
-
0
-
V
3.6.2. Decrease Voltage Drop
The power supply range of the module is from 3.3V to 4.3V. Make sure the input voltage will never drop
below 3.3V. The following figure shows the voltage drop during transmitting burst in
4
G network.
VBAT
Transmit
burst
Transmit
burst
Min.3.3V
Ripple
Drop
Figure 7: Power Supply Limits during Transmit Burst
To decrease voltage drop, a bypass capacitor of about 100µF with low ESR should be used. Multi-layer
ceramic chip (MLCC) capacitor can provide the best combination of low ESR. The main power supply
from an external application has to be a single voltage source and expanded to two sub paths with star
structure. The width of VBAT_BB trace should be no less than 1mm; and the width of VBAT_RF trace
should be no less than 2mm. In principle, the longer the VBAT trace is, the wider it will be.
Three ceramic capacitors (100nF, 33pF, 10pF) are recommended to be applied to the VBAT pins. The
capacitors should be placed close to the VBAT pins. In addition, in order to get a stable power source, it is
suggested that you should use a zener diode of which reverse zener voltage is 5.1V and dissipation
power is more than 0.5W. The following figure shows the star structure of the power supply.