Quectel Smart LTE Module Series Hardware Design page 55

Table 12: Pin Definition of SD Card Interface
Pin Name Pin No.
SD_LDO11 63
SD_LDO12 179
SD_CLK 70
SD_CMD 69
SD_DATA0 68
SD_DATA1 67
SD_DATA2 66
SD_DATA3 65
SD_DET 64
A reference circuit for SD card interface is shown as below.
SD_DATA2
SD_DATA3
SD_CMD
R10
SD_CLK
R11
SD_DATA0
R12
SD_DATA1
R13
SD_DET
Module
SD_LDO11 is a peripheral driver power supply for SD card. The maximum drive current is approx. 800mA.
Because of the high drive current, it is recommended that the trace width is 0.5mm or above. In order to
ensure the stability of drive power, a 4.7uF and a 33pF capacitor should be added in parallel near the SD
card connector.
SC650T_Hardware_Design
I/O Description
PO Power supply for SD card
SD card pull-up power
PO
supply
High speed digital clock
DO
signal of SD card
I/O Command signal of SD card
I/O
High speed bidirectional
I/O
digital signal lines of SD
I/O
card
I/O
DI SD card insertion detection
LDO5_1P8
R1 R2 R3
120K
NM_51K NM_51K NM_10K NM_51K NM_51K
R7
33R
R8 33R
R9
33R
33R
33R
33R
1K
D1 D2
D3
Figure 17: Reference Circuit for SD Card Interface
Comment
Vnorm=2.95V
I max=800mA
O
Support 1.8V or 2.95V power supply.
The maximum drive current is 50mA.
Control characteristic impedance as
50Ω.
Active low.
SD_LDO11
SD_LDO12
R6
R4 R5
C1
D4 D5 D7
D6
4.7uF
Smart LTE Module Series
SC650T Hardware Design
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
33pF
GND
13
GND
SD Card Connector
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