Product Info
Table Of Contents
- About the Document
- Contents
- Table Index
- Figure Index
- 1Introduction
- 2Product Concept
- 3Application Interfaces
- 3.1.General Description
- 3.2.Pin Assignment
- 3.3.Pin Description
- 3.4.Power Supply
- 3.5.Turn on and off Scenarios
- 3.6.VRTC Interface
- 3.7.Power Output
- 3.8.Battery Charge and Management
- 3.9.USB Interface
- 3.10.UART Interfaces
- 3.11.(U)SIM Interfaces
- 3.12.SD Card Interface
- 3.13.GPIO Interfaces
- 3.14.I2C Interfaces
- 3.15.ADC Interfaces
- 3.16.Motor Drive Interface
- 3.17.LCM Interface
- 3.18.Touch Panel Interface
- 3.19.Camera Interfaces
- 3.20.Sensor Interfaces
- 3.21.Audio Interfaces
- 3.22.Emergency Download Interface
- 4Wi-Fi and BT
- 5GNSS
- 6Antenna Interface
- 7Electrical, Reliability and Radio Characteristics
- 8Mechanical Dimensions
- 9Storage, Manufacturing and Packaging
- 10Appendix A References
- 11Appendix B GPRS Coding Schemes
- 12Appendix C GPRS Multi-slot Classes
- 13Appendix D EDGE Modulation and Coding Schemes
Smart LTE Module Series
SC20 Hardware Design
SC20_Hardware_Design Confidential / Released
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Figure 19: Reference Circuit for SD Card Interface
SD_LDO11 is a peripheral driver power supply for SD card. The maximum drive current is approx. 600mA.
Because of the high drive current, it is recommended that the trace width is 0.6mm or more. In order to
ensure the stability of drive power, a 2.2uF capacitor should be added in parallel near the SD card
connector.
CMD, CLK, DATA0, DATA1, DATA2 and DATA3 are all high speed signal lines. In PCB design, please
control the characteristic impedance of them as 50Ω, and do not cross with other traces. It is
recommended to route the trace on the inner layer of PCB, and keep the same trace length for CLK, CMD,
DATA0, DATA1, DATA2 and DATA3. CLK additionally needs ground shielding.
Layout guidelines:
Control impedance as 50Ω±10%, and ground shielding is required.
The total trace length difference between CLK and other signal line traces should not exceed 1mm.
Table 15: SD Card Trace Length Inside the Module
Pin No.
Signal
Length (mm)
Comment
39
SD_CLK
14.60
40
SD_CMD
14.55
41
SD_DATA0
14.53
42
SD_DATA1
14.56
43
SD_DATA2
14.53