Audio Interface; Analogue Audio - Huawei MU509 Series Hardware Manual

HUAWEI MU509 Series HSDPA LGA Module
Hardware Guide
 To meet the requirements of 3GPP TS 51.010-1 protocols and electromagnetic
compatibility (EMC) authentication, the SIM card socket should be placed near the
LGA interface (it is recommended that the PCB circuit connecting the LGA
interface and the SIM card socket 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 SIM_CLK and
SIM_DATA signal wires with a ground wire. The GND pin of the SIM card socket
and the GND pin of the SIM card must be well connected to the power GND pin
supplying power to the MU509 module.
A 0.1 μF or a 0.22 μF capacitor and a 1 μF capacitor are placed between the

SIM_VCC and GND pins in a parallel manner. Three 10 pF capacitors are placed
between the SIM_DATA and GND pins, the SIM_RST and GND pins, and the
SIM_CLK and GND pins in parallel to filter interference from RF signals.

You do not need to pull the SIM_DATA pin up during design as a 20000-Ω resistor
is used to connect the SIM_DATA pin to the VSIM pin.
 It is recommended to take electrostatic discharge (ESD) protection measures near
the USIM card 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 MU509 module.

3.8 Audio Interface

3.8.1 Analogue Audio

The MU509 provides two audio I/O channels (Data only does not support the voice
function).
The two audio I/O channels are completely different and thus have good performance
of resisting RF interferences. The routes on the printed circuit board (PCB) should be
placed in parallel with each other and should be short. The filter circuit on the two
sides should be symmetric. The differential signals should be close to each other. The
audio output signals in differential pairs and the audio input signals in differential pairs
should be separated effectively through ground. In addition, the audio signals should
be located away from the circuits of the power supply, RF, and antenna.
The first audio channel can be used for the handset without requiring any audio
amplifier. The output power for the differential ear output is typically 50 mW into a 32
Ω speaker.
The second audio channel can be used for the hands-free without requiring any audio
amplifier. The output pins are configured differently, with a rated output of 500 mW into
an 8 Ω speaker. Considerable current flows between the audio output pins and the
speaker, and thus wide PCB traces are recommended (20 mils).
Issue 09 (2014-03-06)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
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