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VDDSD is the power supply for SD card. The maximum drive current is 400 mA. Because of the large
drive current, it is recommended that the trace width is 0.5 mm or above. To ensure the stability of drive
power, add 4.7 μF and 33 pF capacitors in parallel near the SD card connector.
SD_CMD, SD_CLK, SD_DATA0, SD_DATA1, SD_DATA2 and SD_DATA3 are all high-speed signal lines.
In PCB design, control the impedance of them as 50 Ω ±10 %, and do not cross them with other traces.
Meanwhile, it is recommended to route these traces on the inner layer of PCB, and keep them of the
same length. Additionally, SD_CLK needs separate ground shielding.
Trace length requirements:
⚫
Control impedance as 50 Ω ±10 %, and add ground shielding.
⚫
The trace length difference between SD_CLK and SD_CMD/SD_DATA should be less than 1 mm.
Table 15: SD Card Signal Trace Length Inside Module
Pin No.
39
40
41
42
43
44
NOTE
1.
The maximum output current of VDDSD is 400 mA. It is suggested to add an LDO with output
current of 1 A if an external large-capacity SD card is needed.
2.
VDDSDIO is only used for pulling up SD_DATA and SD_CMD and cannot supply power to other
peripherals.
SC200K_Series_Hardware_Design
Pin Name
SD_CLK
SD_CMD
SD_DATA0
SD_DATA1
SD_DATA2
SD_DATA3
Smart Module Series
Length (mm)
34.25
36.32
33.27
32.71
32.63
33.36
51 / 105
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