Power Supply Vbat Interface - Huawei MU709 Series Hardware Manual

HUAWEI MU709 Series HSPA+ LGA Module
Hardware Guide
Table 3-2 Definitions of the pins on the power supply interface
Pin
Pin No.
Name
12 and 13 VBAT
48, 50, 52,
54, 56, 58,
59, 106,
GND
108, 110,
112, 114
and 116
VCC_E
32
XT1
USIM_
34
VCC
92 SD_VC
C
121–145 GND

3.3.2 Power Supply VBAT Interface

When the MU709 module works normally, power is supplied through the VBAT pins
and the voltage ranges from 3.3 V to 4.2 V (typical value: 3.8 V). The 145-pin LGA
provides two VBAT pins and some GND pins for external power input. To ensure that
the MU709 module works normally, all the pins must be used efficiently.
When the MU709 module is used for different external applications, pay special
attention to the design for the power supply. When the MU709 module works at 2G
mode and transmits signals at the maximum power, the transient current may reach
the transient peak value of about 2.75 A due to the differences in actual network
environments. In this case, the VBAT voltage drops. If you want wireless good
performance, please make sure that the voltage does not decrease below 3.3 V in any
case. Otherwise, exceptions such as restart of the MU709 module may occur.
A low-dropout (LDO) regulator or switch power with current output of more than 3 A is
recommended for external power supply. Furthermore, five 220 µF or above energy
storage capacitors are connected in parallel at the power interface of the MU709
Issue 09 (2017-12-15)
Pad
Description
Type
Power supply
input.
The rising time of
PI
VBAT must be
greater than 100
us
- GND
Pin for external
PO
power output
Power supply for
PO
USIM card
PO SD Card Power.
Only used for
debugging.
Please reserve
the test point.
Thermal Ground
-
Pad
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
Min. Typ.
Parameter
(V) (V)
-
3.3 3.8
- - -
-
1.75 1.8
-
–0.3
1.8
–0.3
3.0
- 2.9 3.0
- - -
Max.
Comments
(V)
4.2
- -
-
1.85
USIM_VCC
1.98
=1.8 V
3.3 USIM_VCC
=3.0 V
3.1
- -
24