Audio Interface; Analogue Audio - Huawei MC509 Series Hardware Manual

HUAWEI MC509 Series CDMA LGA Module
Hardware Guide

To meet the requirements of 3GPP TS 11.11protocols and electromagnetic
compatibility (EMC) authentication, the RUIM card socket should be placed near
the LGA interface (it is recommended that the PCB circuit connecting the LGA
interface and the RUIM card socket not exceed 100mm), because a long circuit
may lead to wave distortion, thus affecting signal quality.
 It is recommended that the user should wrap the area adjacent to the RUIM_CLK
and RUIM_DATA signal wires with a ground wire. The GND pin of the RUIM card
socket and the GND pin of the RUIM card must be well connected to the power
GND pin supplying power to the MC509 module.
A 0.1 μF capacitor and1 μF capacitor are placed between the RUIM_VCC and

GND pins in a parallel manner (If RUIM_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 RUIM_DATA and Ground pins, the RUIM_RST
and Ground pins, and the RUIM_CLK and Ground pins in parallel to filter
interference from RF signals.
 It is not recommended that pull the RUIM_DATA pin up during design as a 15000-
ohm resistor is used to connect the RUIM_DATA pin to the RUIM_VCC.
 It is recommended to take electrostatic discharge (ESD) protection measures near
the RUIM 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 MC509 module.

3.8 Audio Interface

3.8.1 Analogue Audio

The MC509 provides two audio channels (Data only doesn't support the voice
function).
The two audio 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 circuits, 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 for a full-
scale +3 dBm sine wave into a 32-ohm 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 02 (2013-05-06)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
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