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SD_DATA2
SD_DATA3
SD_CMD
SD_CLK
SD_DATA0
SD_DATA1
SD_DET
GND
Module
SD_LDO11 is the power supply for the SD card and can provide up to 800 mA output current. Due to the
high output current, it is recommended that the trace width should be at least 0.8 mm. In order to ensure
stability of output current, add a 4.7 μF and a 33 pF capacitor 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 characteristic impedance of them to 50 Ω, and do not cross them with other
traces. It is recommended to route the traces on the inner layer of PCB and keep them of the same length.
Additionally, SD_CLK needs ground shielding separately.
Layout guidelines:
⚫
Control the impedance to 50 Ω ± 10 % and add ground shielding.
⚫
The trace length difference between SD_CLK and other signal traces like SD_CMD and SD_DATA
should not exceed 1 mm.
Table 14: SD Card Trace Length Inside the Module
Pin No.
39
40
41
42
43
SC262R_Series_Hardware_Design
LDO 5_1V8
R1
R2
R3
120K
NM_51K
NM_51K NM_10K NM_51K NM_51K
R7
33R
R8
33R
R9
33R
R10
33R
R11
33R
R12
33R
R13
1K
D1
D2
D3
Figure 18: Reference Circuit for SD Card Interface
Signal
SD_CLK
SD_CMD
SD_DATA0
SD_DATA1
SD_DATA2
SD_LDO11
SD_LDO12
R6
R4
R5
R14
0R
C1
D4
D5
D7
D6
4.7 μF
Length (mm)
21.50
21.40
21.45
21.60
21.40
Smart Module Series
1
P1-DAT2
2
P2-CD/DAT3
3
P3-CMD
4
P4-VDD
5
P5-CLK
6
P6-VSS
7
P7-DAT0
8
P8-DAT1
9
DETECTIVE
10
GND
D8
C2
11
GND
12
33 pF
GND
13
GND
SD Card Connector
50 / 115
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