User's Manual

Smart Machine Smart Decision
SIM868_Hardware_Design_V1.00 8 2016-06-20
Figure Index
FIGURE 1: SIM868 FUNCTIONAL DIAGRAM .......................................................................................................14
FIGURE 2: PIN OUT DIAGRAM (TOP VIEW).........................................................................................................15
FIGURE 3: DIMENSIONS OF SIM868 (UNIT: MM) ................................................................................................18
FIGURE 4: RECOMMENDED PCB FOOTPRINT OUTLINE (UNIT: MM) ..............................................................19
FIGURE 5: REFERENCE CIRCUIT OF THE VBAT/GPS_VBAT INPUT .................................................................20
FIGURE 6: REFERENCE CIRCUIT OF THE LDO POWER SUPPLY ......................................................................20
FIGURE 7: REFERENCE CIRCUIT OF THE DC-DC POWER SUPPLY ..................................................................21
FIGURE 8: VBAT VOLTAGE DROP DURING TRANSMIT BURST ........................................................................21
FIGURE 9: THE MINIMAL VBAT VOLTAGE REQUIREMENT AT VBAT DROP...................................................21
FIGURE 10: POWERED ON/DOWN MODULE USING TRANSISTOR ..................................................................22
FIGURE 11: POWERED ON/DOWN MODULE USING BUTTON ..........................................................................22
FIGURE 12: TIMING OF POWER ON MODULE.....................................................................................................22
FIGURE 13: TIMING OF POWER OFF SIM868 BY PWRKEY ................................................................................23
FIGURE 14: TIMING OF RESTART SIM868 ............................................................................................................24
FIGURE 15: RTC SUPPLY FROM CAPACITOR ......................................................................................................26
FIGURE 16: RTC SUPPLY FROM NON-CHARGEABLE BATTERY .......................................................................26
FIGURE 17: RTC SUPPLY FROM RECHARGEABLE BATTERY ...........................................................................27
FIGURE 18: CONNECTION OF THE SERIAL INTERFACES .................................................................................29
FIGURE 19: RESISTOR MATCHING CIRCUIT .......................................................................................................29
FIGURE 20 : DIODE ISOLATION CIRCUIT ............................................................................................................29
FIGURE 21: TX LEVEL MATCHING CIRCUIT .......................................................................................................30
FIGURE 22: RX LEVEL MATCHING CIRCUIT .......................................................................................................30
FIGURE 23: USB REFERENCE CIRCUIT ................................................................................................................30
FIGURE 24: CONNECTION FOR SOFTWARE UPGRADING AND DEBUGGING ................................................31
FIGURE 25: UART1_RI BEHAVIOUR OF VOICE CALLING AS A RECEIVER .....................................................32
FIGURE 26: UART1_RI BEHAVIOUR OF URC OR RECEIVE SMS .......................................................................32
FIGURE 27: UART1_RI BEHAVIOUR AS A CALLER .............................................................................................32
FIGURE 28: SPEAKER REFERENCE CIRCUIT ......................................................................................................33
FIGURE 29: MICROPHONE REFERENCE CIRCUIT ..............................................................................................34
FIGURE 30: REFERENCE CIRCUIT OF THE 8-PIN SIM CARD HOLDER ............................................................35
FIGURE 31: REFERENCE CIRCUIT OF THE 6-PIN SIM CARD HOLDER ............................................................36
FIGURE 32: MOLEX 91228 SIM CARD HOLDER ..................................................................................................37
FIGURE 33: AMPHENOL C707 10M006 512 SIM CARD HOLDER ........................................................................38
FIGURE 34: SD REFERENCE CIRCUIT ..................................................................................................................39
FIGURE 35: REFERENCE CIRCUIT OF NETLIGHT...............................................................................................41
FIGURE 36: RF_SYNC SIGNAL DURING TRANSMIT BURST .............................................................................42
FIGURE 37: GSM ANTENNA MATCHING CIRCUIT ..............................................................................................43
FIGURE 38: GSM ANTENNA MATCHING CIRCUIT WITHOUT RF CONNECTOR..............................................43
FIGURE 39: GNSS PASSIVE ANTENNA MATCHING CIRCUIT ............................................................................47
FIGURE 40: GNSS ACTIVE ANTENNA MATCHING CIRCUIT..............................................................................47
FIGURE 41: PIN ASSIGNMENT ..............................................................................................................................48
FIGURE 42: TOP AND BOTTOM VIEW OF SIM868 ...............................................................................................55
FIGURE 43: TYPICAL SOLDER REFLOW PROFILE OF LEAD-FREE PROCESS .................................................55