Audio Interface - Huawei ME909u-521 Hardware Manual

HUAWEI ME909u-521 LTE 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 ME909u-521 module.
 A 100 nF capacitor (0402 package is recommended so that greater capacitance
such as 1 µF can be employed if necessary) and a 33 pF capacitor are placed
between the USIM_VCC and Ground pins in parallel. 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.
 USIM_DATA is already pulled up internally.
 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 ME909u-521 module.
 The ESD protection component should choose low capacitance. The capacitance
of the component should be lower than 10 pF.

3.8 Audio Interface

ME909u-521 module provided one PCM digital audio interface. Table 3-9 lists the
signals on the digital audio interface.
Table 3-9 Signals on the digital audio interface
Pin Pin Name
No.
5 PCM_SYNC
6 PCM_DIN
7 PCM_DOUT
8 PCM_CLK
Issue 05 (2017-12-15)
Pad Description
Type
O PCM interface sync
I PCM interface data in
O PCM interface data
out
O PCM interface clock
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Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
Parameter Min.
(V)
V 1.35
OH
V 0
OL
V 1.17
IH
–0.3
V
IL
V 1.35
OH
V 0
OL
V 1.35
OH
V 0
OL
Typ. Max. Comments
(V) (V)
1.8 1.8 -
- 0.45 -
1.8 2.1 -
- 0.63 -
1.8 1.8 -
- 0.45 -
1.8 1.8 -
- 0.45 -
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