Product Info

LTE Standard Module Series
EC25 Series Hardware Design
EC25_Series_Hardware_Design 40 / 126
3.6. Power Supply
3.6.1. Power Supply Pins
EC25 provides four VBAT pins for connection with the external power supply. There are two separate
voltage domains for VBAT.
⚫ Two VBAT_RF pins for module’s RF part
⚫ Two VBAT_BB pins for module’s baseband part
The following table shows the details of VBAT pins and ground pins.
Table 6: VBAT and GND Pins
3.6.2. Decrease Voltage Drop
The power supply range of EC25 is from 3.3 V to 4.3 V. Please make sure that the input voltage will never
drop below 3.3 V. The following figure shows the voltage drop during burst transmission in 2G network.
The voltage drop will be less in 3G and 4G networks.
错误!不能通过编辑域代码创建对象。
Figure 6: Power Supply Limits during Burst Transmission
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 (MLCC) capacitor array should also be reserved due to its ultra-low
ESR. It is recommended to use three ceramic capacitors (100 nF, 33 pF, 10 pF) for composing the MLCC
array, and place these capacitors close to VBAT_BB/VBAT_RF pins. The main power supply from an
external application has to be a single voltage source and can be expanded to two sub paths with star
structure. The width of VBAT_BB trace should be no less than 1 mm; and the width of VBAT_RF trace
should be no less than 2 mm. In principle, the longer the VBAT trace is, the wider it will be.
In addition, in order to avoid the damage caused by electric surge and ESD, it is suggested that a TVS
Pin Name
Pin No.
Description
Min.
Typ.
Max.
Unit
VBAT_RF
57, 58
Power supply for module’s RF
part
3.3
3.8
4.3
V
VBAT_BB
59, 60
Power supply for module’s
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