Hardware Design SIM800L (SIMCom) - 8

Smart Machine Smart Decision Figure Index
Figure 1: SIM800L functional diagram .14
Figure 2: SIM800L pin out diagram (Top view).15
Figure 3: Dimensions of SIM800L (Unit: mm) .19
Figure 4: Recommended PCB footprint outline (Unit: mm) .20
Figure 5: Reference circuit of the VBAT input.21
Figure 6: Reference circuit of the LDO power supply.21
Figure 7: Reference circuit of the DC-DC power supply .22
Figure 8: VBAT voltage drop during transmit burst .22
Figure 9: The minimal VBAT voltage requirement at VBAT drop.23
Figure 10: Powered on/down module using transistor .23
Figure 11: Powered on/down module using button .23
Figure 12: Timing of power on module .24
Figure 13: Timing of power down SIM800L by PWRKEY .25
Figure 14: Reset circuit .26
Figure 15: Reset timing sequence .27
Figure 16: RTC supply from capacitor .28
Figure 17: RTC supply from non-chargeable battery .29
Figure 18: RTC supply from rechargeable battery.29
Figure 19: Connection of the serial interfaces .31
Figure 20: Resistor matching circuit.31
Figure 21 : Diode isolation circuit .32
Figure 22: TX level matching circuit.32
Figure 23: RX level matching circuit.32
Figure 24: USB reference circuit .33
Figure 25: Connection for software upgrading and debugging .34
Figure 26: RI behaviour of voice calling as a receiver .35
Figure 27: RI behaviour of data calling as a receiver .35
Figure 28: RI behaviour of URC or receive SMS.36
Figure 29: RI behaviour as a caller .36
Figure 30: Speaker reference circuit .37
Figure 31: Speaker with amplifier reference circuit .37
Figure 32: Reference circuit of the 8-pin SIM card holder.39
Figure 33: Reference circuit of the 6-pin SIM card holder.40
Figure 34: Molex 91228 SIM card holder .41
Figure 35: Amphenol C707 10M006 5122 SIM card holder .42
Figure 36: PCM reference circuit .44
Figure 37: LCD reference circuit .44
Figure 38: SD reference circuit.44
Figure 39: 25 keys reference circuit.45
Figure 40: 50 keys reference circuit.46
Figure 41: Keypad reference circuit.46
Figure 42: Keypad detected .46
Figure 43: Reference circuit of PWM driver buzzer.49
Figure 44: Reference circuit of NETLIGHT.50
Figure 45: LED driver reference circuit.51
Figure 46: BPI_BUS1 signal during transmit burst .52
SIM800L_Hardware_Design_V1.00 8 2013-08-20