Audio Interface - Huawei MU709 Series Hardware Manual

HUAWEI MU709 Series HSPA+ LGA Module
Hardware Guide


To meet the requirements of 3GPP TS 51.010-1 protocols and electromagnetic
compatibility (EMC) authentication, the USIM socket should be placed near the
LGA interface (it is recommended that the PCB circuit connects the LGA interface
and the USIM socket does not exceed 100 mm), because a long circuit may lead to
wave distortion, thus affecting signal quality.

It is recommended that you wrap the area adjacent to the USIM_CLK and
USIM_DATA signal wires with ground. The Ground pin of the USIM socket and the
Ground pin of the USIM card must be well connected to the power Ground pin
supplying power to the MU709 module.
A 100 nF capacitor and 1 μF capacitor are placed between the USIM_VCC and

GND pins in a parallel manner (If USIM_VCC circuit is too long, that the larger
capacitance such as 4.7 μF can be employed if necessary). Three 33 pF
capacitors are placed between the USIM_DATA and Ground pins, the
USIM_RESET and Ground pins, and the USIM_CLK and Ground pins in parallel to
filter interference from RF signals.
 It is recommended to take electrostatic discharge (ESD) protection measures near
the USIM socket. The TVS diode with Vrwm of 5 V and junction capacitance less
than 10 pF must be placed as close as possible to the USIM socket, and the
Ground pin of the ESD protection component is well connected to the power
Ground pin that supplies power to the MU709 module.
It is recommended to place a 1 kΩ resistor in series on the USIM_DET interface for

ESD protection if USIM_DET is used.

3.8 Audio Interface

MU709 module provides one PCM digital audio interface. Table 3-11 lists the signals
on the digital audio interface.
Table 3-11 Signals on the digital audio interface
Pin Pin Name Pad
No. Type
5 PCM_SYNC O
6 PCM_DIN I
7 PCM_DOUT O
Issue 09 (2017-12-15)
If the USIM card is absent, USIM_DET pin should be low, and the CD is
connected to ground.
Description Parameter
PCM sync V
V
PCM data in V
V
PCM data out V
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
Min. Typ.
(V) (V)
1.35 1.80
OH
0 -
OL
1.26 1.80
IH
–0.30
-
IL
1.35 1.80
OH
Max. Comments
(V)
2.10 The pin is output when the
module is used as PCM
0.45
master; input when the
module is used as PCM
slave.
2.10 -
0.63
2.10 -
38