hardware design v1 00 2

Smart Machine Smart Decision
SIM900R_Hardware Design_V1.00 6 2012-07-20
Figure Index
Figure 1: SIM900R functional diagram ................................................................................................................11
Figure 2: SIM900R pin out diagram (Top view).................................................................................................. 12
Figure 3: Dimensions of SIM900R（Unit: mm）............................................................................................... 15
Figure 4: Recommended PCB footprint outline（Unit: mm）............................................................................ 15
Figure 5: Reference circuit of the LDO power supply......................................................................................... 16
Figure 6: Reference circuit of the DC-DC power supply..................................................................................... 16
Figure 7: VBAT voltage drop during transmit burst............................................................................................. 17
Figure 8: The minimal VBAT voltage requirement at VBAT drop ...................................................................... 17
Figure 9: Powered on/down module using transistor........................................................................................... 17
Figure 10: Powered on/down module using button.............................................................................................. 18
Figure 11: Timing of power on module................................................................................................................ 18
Figure 12: Timing of power down SIM900R by PWRKEY ................................................................................ 19
Figure 13: Timing of restart SIM900R................................................................................................................. 20
Figure 14: RTC supply from capacitor................................................................................................................. 22
Figure 15: RTC supply from non-chargeable battery........................................................................................... 22
Figure 16: RTC supply from rechargeable battery ............................................................................................... 22
Figure 17: Seiko XH414H-IV01E Charge-Discharge Characteristic................................................................... 23
Figure 18: Connection of the serial interfaces...................................................................................................... 23
Figure 19: Connection of RXD and TXD only .................................................................................................... 24
Figure 20: Connection for software upgrading and debugging............................................................................ 25
Figure 21: Speaker reference circuit .................................................................................................................... 25
Figure 22: Speaker with amplifier reference circuit............................................................................................. 26
Figure 23 : Microphone reference circuit............................................................................................................. 26
Figure 24: Earphone reference circuit.................................................................................................................. 27
Figure 25: Reference circuit of the 8-pin SIM card holder .................................................................................. 28
Figure 26: Reference circuit of the 6-pin SIM card holder .................................................................................. 28
Figure 27: Amphenol C707 10M006 5122 SIM card holder................................................................................ 29
Figure 28: Molex 91228 SIM card holder............................................................................................................ 30
Figure 29: Reference circuit of the keypad interface ........................................................................................... 31
Figure 30: RI behaviour of voice calling as a receiver......................................................................................... 32
Figure 31: RI behaviour of data calling as a receiver........................................................................................... 32
Figure 32: RI behaviour of URC or receive SMS ................................................................................................ 33
Figure 33: RI behaviour as a caller ...................................................................................................................... 33
Figure 34: Reference circuit of NETLIGHT........................................................................................................ 33
Figure 35: Reset timing ........................................................................................................................................ 34
Figure 36: Reset reference design circuit ............................................................................................................. 35
Figure 37: Antenna matching circuit.................................................................................................................... 35
Figure 38: Top and bottom view of SIM900R ..................................................................................................... 43
Figure 39: Module information............................................................................................................................ 43
Figure 40: Typical solder reflow profile............................................................................................................... 44