Audio Interfaces; Pcm Interface - Quectel EC2 Series Design Manualline

DVDD_1V1 is output by AR8033's LX pin through an LC circuit. The 4.7 μH inductor in the LC circuit
should be able to provide 1 A current with low direct current resistance. The trace width for the inductor is
recommended to be at least 1 mm. Besides, there is a reference ground plane needed for inductance
isolation near the 4.7 μH inductor The following figure shows the recommended inductor placement as
well as trace routing and trace width for AR8033 pins.
RJ45
RJ45
Figure 18: Layout of Recommended 4.7 μH Inductor, GND and Traces of AR8033 (EVB 1st Layer)

3.5. Audio Interfaces

3.5.1. PCM Interface


The filter capacitors for PCM_CLK/PCM_SYNC should be placed close to the two pins.

The PCM bus is recommended to be routed on inner layers, and it is recommended that each trace
be surrounded by ground traces separately. If there are limits of space, at least ensure PCM_CLK is
surrounded by ground traces, and other three signal traces can be surrounded together by ground
traces.

PCM traces should be kept away from interference sources such as clock, RF, crystals, power
supplies, etc.
EC2x&EG2x-G_Series_PCB_Design_Guideline
Network
Network
GND
GND
transformer
transformer
GND
GND
LTE Standard Module Series
EC2x&EG2x-G Series PCB Design Guideline
GND
GND
GND
GND
4.7 μH inductor
4.7 μH inductor
GND
GND
≥ 1 mm
≥ 1 mm
GND
GND
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