Vbat Interface - Huawei MG301 Hardware Manual

HUAWEI MG301 B2B Module
HardwareGuide
Table 3-2 Definitions of the pins on the power supply interface
Pin No.
42, 44, 46, 48, 50
41, 43, 45, 47, 49
35
40

3.3.2 VBAT Interface

When the MG301 B2B module works normally, power is supplied through the VBAT
pins and the voltage ranges from 3.3 V to 4.8 V (typical value: 3.8 V). The 50-pin B2B
connector provides five VBAT pins and five GND pins for external power input. To
ensure that the MG301 module works normally, all the pins must be used efficiently.
When the MG301 B2B module is used for different external applications, pay special
attention to the design for the power supply. When the MG301 B2B module transmits
signals at the maximum power, the transient current may reach the transient peak
value of about 2.0 A due to the differences in actual network environments. In this
case, the VBAT voltage greatly drops. Make sure that the voltage does not decrease
below 3.3 V in any case. Otherwise, exceptions such as restart of the MG301 B2B
module may occur.
A low-dropout (LDO) regulator or switch power with current output of more than 2 A is
recommended for external power supply. Furthermore, At least five 220 µF storage
capacitors should be connected in parallel at the power interface of the MG301 B2B
module. In addition, to reduce the impact of channel impedance on voltage drop, you
are recommended to try to shorten the power supply circuit of the VBAT interface.
It is recommended to employ a ferrite bead in series on VBAT power circuit to
improve the EMI performance. And the rated current of the ferrite bead is required at
least 2 A.
Figure 3-2 shows the recommended power circuit of MG301 B2B module.
Figure 3-2 Recommended power circuit of MG301 B2B module
Signal Name
VBAT
GND
VCOIN
VIO
Module
(DCE)
VBAT
10 μF
100 nF 220 μF 220 μF 220 μF 220 μF 220 μF
Description of the Application Interfaces
I/O Description
P Pins for Power supply input
- GND
P Pin for standby power input of
the RTC
P Pin for external power output
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Huawei Proprietary and Confidential Copyright ©
Huawei Technologies Co., Ltd
Issue 06 (2013-06-13)
VBAT
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