Input Power Supply Interface - Huawei MU509-65 HSDPA Hardware Manual

HUAWEI MU509-65 HSDPA LGA Module
Hardware Guide

3.3.2 Input Power Supply Interface

VBAT Interface
When the MU509-65 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 module
provides VBAT pins and GND pins for external power input. To ensure that the
MU509-65 module works normally, all the pins must be used efficiently.
If you want good wireless performance, please make sure that the voltage does not
drop below 3.2 V in any case. Otherwise, exceptions such as restart of the 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, at least five 220 µF storage
capacitors are connected in parallel at the power interface of the MU509-65 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 that add the EMI ferrite bead (FBMJ1608HS280NT manufactured
by TAIYO YUDEN or MPZ1608S300ATAH0 manufactured by TDK is recommended)
to directly isolate DTE from DCE in the power circuit. In addition, the ESD diode
(BAT60B E6327 manufactured by INFINEON is recommended) should be added.
Figure 3-3 shows the recommended power circuit of MU509-65 module.
Figure 3-3 Recommended power circuit of MU509-65 module
VCOIN Interface
VCOIN pin of MU509-65 module is used as an analog input from the 3 V coin cell for
Sudden Momentary Power Loss (SMPL) and RTC keep-alive power. A capacitor
(rather than a coin cell) can be used if only SMPL is supported (not RTC). VCOIN pin
is also used as an analog output for a coin cell or a capacitor charging.
If RTC is used, a manganese-lithium rechargeable battery is recommended, for
example, the SII Micro Parts HB-414 and the Panasonic ML-series. Two sets of coin
cell specifications are compared in Table 3-3 . When the MU509-65 is off, RTC and its
oscillator source are still active, provided by a coin cell battery which is installed. This
allows continued monitoring of RTC alarms programmed via software.
Issue 01 (2016-04-08)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
23