Smart Module Series
SC606T Series Hardware Design
SC606T_Series_Hardware_Design 51 / 116
SD_CMD
120K
NM_51K
SD_DATA3
SD_DATA2
LDO5_1P8
SD_CLK
SD_DATA0
SD_DET
SD_DATA1
P1-DAT2
P2-CD/DAT3
P3-CMD
P4-VDD
P5-CLK
P8-DAT1
GND
P6-VSS
P7-DAT0
DETECTIVE
GND
GND
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
SD_LDO11
33R
33R
33R
33R
33R
33R
1K
33 pF
4.7
μ
F
SD_LDO12
Module
R1
R2
R3
R4
R5
R6
NM_51K NM_10K NM_51K NM_51K
R7
R8
R9
R10
R11
R12
R13
D1
D2
D3
D4
D5
D6
D7
D8
C1
C2
SD Card Connector
Figure 17: Reference Design for SD Card Interface
SD_LDO11 is a peripheral driver power supply for SD card. The maximum drive current of the pin is
approximately 800 mA. Because of the high drive current, it is recommended to keep the trace width at
0.5 mm or above. To ensure the stability of supply power, a 4.7
μF and a 33 pF capacitor should be added
in parallel near the SD card connector.
SD_CMD, SD_CLK, SD_DATA0, SD_DATA1, SD_DATA2, and SD_DATA3 traces are all high speed
signal traces. In PCB design, control the characteristic impedance of these traces at 50
Ω ±10 %, and
avoid crossing them with other traces. It is recommended to route the traces on the inner layer of PCB
and keep their lengths the same. The CLK trace should be encircled by ground traces individually.
Please follow these guidelines in your design:
⚫
SD_DATA0, SD_DATA1, SD_DATA2, and SD_DATA3 should be encircled by ground traces.
⚫
The trace length difference between CLK and other signal traces should not exceed 1 mm.
⚫
Keep the maximum bus capacitance of SD card traces within 15 pF.
Table 14: SD Card Signal Trace Length Inside the Module
Pin No.
Signal
Length (mm)
70
SD_CLK
32.11
69
SD_CMD
32.11
68
SD_DATA0
32.11
67
SD_DATA1
32.11