Sd Card Interface - Quectel EC2 Series Design Manualline

MIC_P
SPK_L
AGND
Figure 21: Overview of Analog Audio Signal Traces (EVB 1st Layer)

3.6. SD Card Interface


Keep SDIO signals far away from other sensitive circuits/signals such as RF circuits, analog signals,
etc, as well as noisy signals such as clock and DC-DC signals, etc.
Keep the impedance of SDIO signal traces at 50 Ω 10 %, maintaining the integrity of the reference

plane. SD_CLK and SD_CMD should be surrounded with ground on the layer and ground planes
above and below. If limited by space, the SD_DATA0 to SD_DATA3 could be surrounded with
ground together.

The total length of each SDIO signal trace should be less than 50 mm, and the difference between
them should be less than 1 mm.

The load capacitance for SD card signals should be less than 15 pF.

If a SD card is applied, a TVS should be placed close to the SD card connector.
EC2x&EG2x-G_Series_PCB_Design_Guideline
SPK1_P
SPK1_M
MIC_N
MIC1_P
SPK2_P
Earphone
SPK_R
application
MIC2_P
LTE Standard Module Series
EC2x&EG2x-G Series PCB Design Guideline
Speaker
Amplifier
MIC1_N
SPK2_M
Handset
Application
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