Sd Card Interface - Quectel SC206E Series Hardware Design

To enhance the reliability and availability of the (U)SIM card in applications, please follow the criteria
below in (U)SIM circuit design:
⚫
Place the (U)SIM card connector as close to the module as possible. Keep the trace length as short
as possible, at most 200 mm.
⚫
Keep (U)SIM card signals away from RF and VBAT traces.
⚫ Reserve a filter capacitor for USIM_VDD, and its maximum capacitance should not exceed 1 μF.
Additionally, place the capacitor near the (U)SIM card connector.
⚫
To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and
shield them with ground. USIM_RST also needs ground protection.
⚫
To ensure better ESD protection, it is recommended to add a TVS array with a parasitic capacitance
not exceeding 10 pF. Add 22 Ω resistors in series between the module and (U)SIM card to suppress
EMI such as spurious transmission. Please note that the (U)SIM peripheral circuit should be close to
the (U)SIM card connector.
⚫
Add 22 pF capacitors in parallel on USIM_DATA, USIM_CLK and USIM_RST signal lines to filter RF
interference, and place them as close to the (U)SIM card connector as possible.

3.12. SD Card Interface

SD Card interface of the module supports SD 3.0 protocol. The pin definition of SD card interface is
shown below.
Table 14: Pin Definition of SD Card Interface
Pin Name Pin No.
SD_CLK 39
SD_CMD 40
SD_DATA0 41
SD_DATA1 42
SD_DATA2 43
SD_DATA3 44
SD_DET 45
SD_LDO21 38
SD_LDO4 32
SC206E_Series_Hardware_Design
I/O Description
DO SD card clock
DO SD card command
DIO SDIO data bit 0
DIO SDIO data bit 1
DIO SDIO data bit 2
DIO SDIO data bit 3
DI SD card hot-plug detect
PO SD card power supply
1.8/2.95 V output power for SD
PO
card pull-up circuits
Smart Module Series
Comment
50 Ω characteristic impedance.
Active low.
-
-
49 / 115