Smart Machine Smart Decision

SIM800C_Hardware_Design_V1.02

7

2015-4-27

Figure Index

FIGURE 1: SIM800C FUNCTIONAL DIAGRAM......................................................................................................... 12

FIGURE 2: PIN OUT DIAGRAM (TOP VIEW) ............................................................................................................. 13

FIGURE 3: DIMENSIONS OF SIM800C (UNIT: MM) ................................................................................................. 15

FIGURE 4: RECOMMENDED PCB FOOTPRINT OUTLINE (UNIT: MM) ................................................................ 16

FIGURE 5: REFERENCE CIRCUIT OF THE VBAT INPUT......................................................................................... 17

FIGURE 6: REFERENCE CIRCUIT OF THE LDO POWER SUPPLY ......................................................................... 17

FIGURE 7: REFERENCE CIRCUIT OF THE DC-DC POWER SUPPLY..................................................................... 18

FIGURE 8: VBAT VOLTAGE DROP DURING TRANSMIT BURST........................................................................... 18

FIGURE 9: THE MINIMAL VBAT VOLTAGE REQUIREMENT AT VBAT DROP .................................................... 18

FIGURE 10: POWERED ON/DOWN MODULE USING TRANSISTOR..................................................................... 19

FIGURE 11: POWERED ON/DOWN MODULE USING BUTTON ............................................................................. 19

FIGURE 12: TIMING OF POWER ON MODULE......................................................................................................... 19

FIGURE 13: TIMING OF POWER OFF SIM800C BY PWRKEY ................................................................................20

FIGURE 14: TIMING OF RESTART SIM800C.............................................................................................................. 22

FIGURE 15: RTC SUPPLY FROM CAPACITOR........................................................................................................... 23

FIGURE 16: RTC SUPPLY FROM NON-CHARGEABLE BATTERY ......................................................................... 24

FIGURE 17: RTC SUPPLY FROM RECHARGEABLE BATTERY .............................................................................. 24

FIGURE 18: CONNECTION OF THE SERIAL INTERFACES..................................................................................... 26

FIGURE 19: RESISTOR MATCHING CIRCUIT ........................................................................................................... 26

FIGURE 20 : DIODE ISOLATION CIRCUIT................................................................................................................. 26

FIGURE 21: TX LEVEL MATCHING CIRCUIT ........................................................................................................... 27

FIGURE 22: RX LEVEL MATCHING CIRCUIT........................................................................................................... 27

FIGURE 23: USB REFERENCE CIRCUIT .................................................................................................................... 27

FIGURE 24: CONNECTION FOR SOFTWARE UPGRADING AND DEBUGGING.................................................. 28

FIGURE 25: UART1_RI BEHAVIOUR OF VOICE CALLING AS A RECEIVER ....................................................... 29

FIGURE 26: UART1_RI BEHAVIOUR OF URC OR RECEIVE SMS.......................................................................... 29

FIGURE 27: UART1_RI BEHAVIOUR AS A CALLER................................................................................................. 29

FIGURE 28: SPEAKER REFERENCE CIRCUIT .......................................................................................................... 30

FIGURE 29: MICROPHONE REFERENCE CIRCUIT.................................................................................................. 30

FIGURE 30: REFERENCE CIRCUIT OF THE 8-PIN SIM CARD HOLDER............................................................... 32

FIGURE 31: REFERENCE CIRCUIT OF THE 6-PIN SIM CARD HOLDER............................................................... 32

FIGURE 32: MOLEX 91228 SIM CARD HOLDER ...................................................................................................... 33

FIGURE 33: AMPHENOL C707 10M006 512 SIM CARD HOLDER........................................................................... 34

FIGURE 34: REFERENCE CIRCUIT OF NETLIGHT .................................................................................................. 35

FIGURE 35: RF_SYNC SIGNAL DURING TRANSMIT BURST ................................................................................ 36

FIGURE 36: GSM ANTENNA MATCHING CIRCUIT ................................................................................................. 37

FIGURE 37: GSM ANTENNA MATCHING CIRCUIT WITHOUT RF CONNECTOR ............................................... 37

FIGURE 38: BLUETOOTH ANTENNA MATCHING CIRCUIT .................................................................................. 38

FIGURE 39: PIN ASSIGNMENT.................................................................................................................................... 39

FIGURE 40: TOP AND BOTTOM VIEW OF SIM800C ................................................................................................ 46

FIGURE 41: TYPICAL SOLDER REFLOW PROFILE OF LEAD-FREE PROCESSES.............................................. 46