User's Manual

SIM900B Hardware Design
Figure Index
FIGURE 1: SIM900B FUNCTIONAL DIAGRAM......................................................................................................... 16
FIGURE 2: TOP VIEW OF SIM900B EVB .................................................................................................................... 17
FIGURE 3: REFERENCE CIRCUIT OF THE VBAT INPUT ........................................................................................ 22
FIGURE 4: REFERENCE CIRCUIT OF THE SOURCE POWER SUPPLY INPUT..................................................... 23
FIGURE 5: VBAT VOLTAGE DROP DURING TRANSMIT BURST........................................................................... 23
FIGURE 6: TURN ON SIM900B USING DRIVING CIRCUIT..................................................................................... 25
FIGURE 7: TURN ON SIM900B USING BUTTON ...................................................................................................... 25
FIGURE 8: TIMING OF TURN ON SYSTEM USING PWRKEY ................................................................................ 26
FIGURE 9: TIMING OF TURN OFF SYSTEM USING PWRKEY............................................................................... 26
FIGURE 10: TIMING OF RESTART SYSTEM ............................................................................................................. 28
FIGURE 11: STATE TRANSITION ................................................................................................................................29
FIGURE 12: RTC SUPPLY FROM NON-CHARGEABLE BATTERY ......................................................................... 30
FIGURE 13: RTC SUPPLY FROM RECHARGEABLE BATTERY .............................................................................. 30
FIGURE 14: RTC SUPPLY FROM CAPACITOR .......................................................................................................... 31
FIGURE 15: SEIKO XH414H-IV01E CHARGE CHARACTERISTIC ......................................................................... 31
FIGURE 16: CONNECTION OF THE SERIAL INTERFACES..................................................................................... 33
FIGURE 17: CONNECTION OF SOFTWARE UPGRADE AND SOFTWARE DEBUG ............................................. 34
FIGURE 18: RS232 LEVEL CONVERTER CIRCUIT................................................................................................... 35
FIGURE 19: SPEAKER INTERFACE CONFIGURATION ........................................................................................... 36
FIGURE 20: SPEAKER INTERFACE WITH AMPLIFIER CONFIGURATION .......................................................... 36
FIGURE 21: MICROPHONE INTERFACE CONFIGURATION................................................................................... 37
FIGURE 22: EARPHONE INTERFACE CONFIGURATION........................................................................................ 37
FIGURE 23: REFERENCE CIRCUIT OF BUZZER ...................................................................................................... 39
FIGURE 24: REFERENCE CIRCUIT OF THE 8 PINS SIM CARD.............................................................................. 41
FIGURE 25: REFERENCE CIRCUIT OF THE 6 PINS SIM CARD.............................................................................. 41
FIGURE 26: AMPHENOL C707 10M006 512 2 SIM CARD HOLDER........................................................................ 42
FIGURE 27: MOLEX 91228 SIM CARD HOLDER ...................................................................................................... 43
FIGURE 28: REFERENCE CIRCUIT OF THE KEYPAD INTERFACE ....................................................................... 45
FIGURE 29: SIM900B SERVICES AS RECEIVER ....................................................................................................... 46
FIGURE 30: SIM900B SERVICES AS CALLER ........................................................................................................... 46
FIGURE 31: REFERENCE CIRCUIT OF NETLIGHT .................................................................................................. 47
FIGURE 32 : THE RF INTERFACE OF MODULE ....................................................................................................... 49
FIGURE 33: TOP AN SIDE MECHANICAL DIMENSIONS OF MODULE （UNIT: MM）.................................... 55
FIGURE 34：MECHANICAL DIMENSIONS OF MODULE PCB DECAL（UNIT: MM）...................................... 56
FIGURE 35: TOP VIEW OF THE SIM900B................................................................................................................... 56
FIGURE 36: SUNCAGEY BB530-06001-20R BOARD-TO-BOARD CONNECTOR.................................................. 57
FIGURE 37 BOARD-TO-BOARD CONNECTOR PHYSICAL PHOTO ...................................................................... 58
FIGURE 38: U.FL-R-SMT............................................................................................................................................... 59
FIGURE 39: U.FL SERIES RF ADAPTER CABLE ....................................................................................................... 60
SIM900B_HD_V1.03 24.06.2010
6