SimCom SIM800 Hardware Design page 7

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Figure Index
FIGURE 1: SIM800 FUNCTIONAL DIAGRAM............................................................................................................ 13
FIGURE 2: SIM800 PIN OUT DIAGRAM (TOP VIEW) ............................................................................................... 14
FIGURE 3: DIMENSIONS OF SIM800 (UNIT: MM) .................................................................................................... 18
FIGURE 4: RECOMMENDED PCB FOOTPRINT OUTLINE (UNIT: MM) ................................................................ 19
FIGURE 5: REFERENCE CIRCUIT OF THE VBAT INPUT......................................................................................... 20
FIGURE 6: REFERENCE CIRCUIT OF THE POWER SUPPLY .................................................................................. 21
FIGURE 7: REFERENCE CIRCUIT OF THE DC-DC POWER SUPPLY ..................................................................... 21
FIGURE 8: VBAT VOLTAGE DROP DURING TRANSMIT BURST ........................................................................... 22
FIGURE 9: THE MINIMAL VBAT VOLTAGE REQUIREMENT AT VBAT DROP .................................................... 22
FIGURE 10: POWER ON/OFF MODULE USING TRANSISTOR ............................................................................... 23
FIGURE 11: POWER ON/OFF MODULE USING BUTTON ........................................................................................ 23
FIGURE 12: TIMING OF POWER ON MODULE ......................................................................................................... 23
FIGURE 13: TIMING OF POWER OFF SIM800 BY PWRKEY ................................................................................... 24
FIGURE 14: RESET CIRCUIT ........................................................................................................................................ 25
FIGURE 15: RESET TIMING SEQUENCE .................................................................................................................... 26
FIGURE 16: RTC SUPPLY FROM CAPACITOR ........................................................................................................... 27
FIGURE 17: RTC SUPPLY FROM NON-CHARGEABLE BATTERY.......................................................................... 28
FIGURE 18: RTC SUPPLY FROM RECHARGEABLE BATTERY .............................................................................. 28
FIGURE 19: CONNECTION OF THE SERIAL PORT................................................................................................... 30
FIGURE 20: LEVEL CONVERTING BY RESISTOR .................................................................................................... 30
FIGURE 21: ISOLATION CIRCUIT BY DIODES ......................................................................................................... 30
FIGURE 22: TX LEVEL CONVERTING BY TRANSISTOR ........................................................................................ 31
FIGURE 23: RX LEVEL CONVERTING BY TRANSISTOR........................................................................................ 31
FIGURE 24: USB REFERENCE CIRCUIT .................................................................................................................... 32
FIGURE 25: CONNECTION FOR SOFTWARE UPGRADING .................................................................................... 33
FIGURE 26: RI BEHAVIOUR OF VOICE CALLING AS A RECEIVER ...................................................................... 33
FIGURE 27: RI BEHAVIOUR OF DATA CALLING AS A RECEIVER ........................................................................ 34
FIGURE 28: RI BEHAVIOUR OF URC OR RECEIVE SMS ........................................................................................ 34
FIGURE 29: RI BEHAVIOUR AS A CALLER ............................................................................................................... 34
FIGURE 30: SPEAKER REFERENCE CIRCUIT .......................................................................................................... 35
FIGURE 31: MICROPHONE REFERENCE CIRCUIT .................................................................................................. 35
FIGURE 32: REFERENCE CIRCUIT OF THE 8-PIN SIM CARD HOLDER ............................................................... 37
FIGURE 33: REFERENCE CIRCUIT OF THE 6-PIN SIM CARD HOLDER ............................................................... 38
FIGURE 34: MOLEX 91228 SIM CARD HOLDER....................................................................................................... 39
FIGURE 35: AMPHENOL C707 10M006 512 SIM CARD HOLDER ........................................................................... 40
FIGURE 36: PCM REFERENCE CIRCUIT .................................................................................................................... 41
FIGURE 37: TRADITIONAL KEYPAD REFERENCE CIRCUIT ................................................................................. 42
FIGURE 38: EXTENDED KEYPAD REFERENCE CIRCUIT ...................................................................................... 42
FIGURE 39: ENHANCE THE ESD PERFORMANCE OF KEYPAD CIRCUIT ........................................................... 43
FIGURE 40: KEYPAD DETECTED ............................................................................................................................... 43
FIGURE 41: GPIO TIMING SEQUENCES .................................................................................................................... 45
FIGURE 42: REFERENCE CIRCUIT OF PWM DRIVE BUZZER ............................................................................... 46
FIGURE 43: REFERENCE CIRCUIT OF NETLIGHT................................................................................................... 47
FIGURE 44: KPLED DRIVER REFERENCE CIRCUIT................................................................................................ 48
FIGURE 45: RF_SYNC SIGNAL DURING TRANSMIT BURST ................................................................................ 48
FIGURE 46: GSM ANTENNA MATCHING CIRCUIT.................................................................................................. 49
SIM800_Hardware Design_V1.10 7 2018-08-13