Huawei MU509 - VBAT Interface Compatibility Design; Detailed Interface Differences; VBAT Interface Design Guide

HUAWEI 30 mm × 30 mm LGA Module
Hardware Migration Guide
LGA Interface Differences
Issue 08 (2016-12-12)
HUAWEI Proprietary and Confidential
Copyright © HUAWEI Technologies Co., Ltd.
38
2.7 VBAT Interface Compatibility Design
2.7.1 Detailed Interface Differences
The VBAT voltage ranges from 3.3 V to 4.2 V, and it ranges from 3.2 V to 4.2 V for
ME909s, with a typical value being 3.8 V. The 30 mm × 30 mm LGA module provides
two VBAT pads.
When the 30 mm × 30 mm LGA module works in the GSM mode, the peak current
can reach 2.75 A. To ensure that the module works normally, place a large-capacity
capacitor (1.1 mF is the best) near VBAT pads. This ensures that the VBAT voltage is
not lower than 3.3 V, and for ME909s, it is not lower than 3.2 V.
All the 30 mm × 30 mm LGA modules must be installed with a large-capacity
capacitor on the VBAT. Furthermore, five 220 µF or above energy storage capacitors
are connected in parallel at the power interface of the LGA module (VBAT Pin). But
for MC509, a 220 µF or above energy storage capacitors in parallel are enough.
Table 2-14 Differences of capacitors in parallel at the VBAT Pin
Pin
No.
Interface
Name
MC509
MU509
MU609
ME209u
-526
ME909u
MU709
ME909s
12
and
13
Power
interface
VBAT
(3.3 V–4.2 V)
VBAT
(3.2 V–4.2 V)
is only for
ME909s
A 220 µF
capacitor
needed
Five 220 µF capacitors needed
2.7.2 VBAT Interface Design Guide
It is recommended that you add ferrite beads and five 220 µF capacitors (a 220 µF
capacitor for MC509) are connected in parallel at VBAT pin to the power circuit. The
diagram of recommended circuit is shown in the following figures.