Sim800 hardware design v1.05
Table Of Contents
- Version History
- 1. Introduction
- 2. SIM800 Overview
- 3. Package Information
- 4. Application Interface
- 4.1. Power Supply
- 4.2. Power on/down SIM800
- 4.3. Power Saving Mode
- 4.4. RTC Backup
- 4.5. Serial Port and USB Interface
- 4.6. RI Behaviors
- 4.7. Audio Interfaces
- 4.8. Bluetooth
- 4.9. SIM Card Interface
- 4.10. PCM Interface
- 4.11. Keypad Interface
- 4.12. I2C BUS
- 4.13. General Purpose Input/Output (GPIO)
- 4.14. ADC
- 4.15. PWM
- 4.16. Network Status Indication
- 4.17. Operating Status Indication
- 4.18. KPLED
- 4.19. RF Synchronization Signal
- 4.20. Antenna Interface
- 5. PCB Layout
- 6. Electrical, Reliability and Radio Characteristics
- 6.1 Absolute Maximum Ratings
- 6.2 Recommended Operating Conditions
- 6.3 Digital Interface Characteristics
- 6.4 SIM Card Interface Characteristics
- 6.5 SIM_VDD Characteristics
- 6.6 VDD_EXT Characteristics
- 6.7 VRTC Characteristics
- 6.8 Current Consumption (VBAT=4V)
- 6.9 Electro-Static Discharge
- 6.10 Radio Characteristics
- 6.11 Module RF Receive Sensitivity
- 6.12 Module Operating Frequencies
- 7. Manufacturing
- 8. Appendix
Smart Machine Smart Decision
card detection function. For details of this AT command, please refer to document [1].
If the SIM card detection function is not used, user can keep the SIM_PRESENCE pin open. The reference
circuit of 6-pin SIM card holder is illustrated in the following figure.
Figure 33: Reference circuit of the 6-pin SIM card holder
4.9.2. SIM Card Design Consideration
SIM card circuit is susceptible to interference, causing the SIM card failures or some other situations, so it is
strongly recommended to follow these guidelines while designing:
z Make sure that SIM card holder should far away from GSM antenna while in PCB layout.
z SIM traces should keep away from RF lines, VBAT and high-speed signal lines.
z The traces should be as short as possible.
z Keep SIM holder’s GND connect to main ground directly.
z Shielding the SIM card signal by ground well.
z Recommended to place a 1uF capacitor on VSIM line and keep close to the holder.
z Add some TVS and the parasitic capacitance should not exceed 50pF, and 22 resistor in serials the
SIM signal could enhance ESD protection.
4.9.3. Design Considerations for SIM Card Holder
For 8 pins SIM card holder, SIMCom recommends to use Molex 91228.User can visit http://www.molex.com
for more information about the holder.
SIM800_Hardware Design_V1.05 39 2014-03-25