Quectel EG91 Series Hardware Design page 10

Figure Index
FIGURE 1: FUNCTIONAL DIAGRAM ............................................................................................................... 20
FIGURE 2: PIN ASSIGNMENT (TOP VIEW) .................................................................................................... 22
FIGURE 3: SLEEP MODE APPLICATION VIA UART ....................................................................................... 31
FIGURE 4: SLEEP MODE APPLICATION WITH USB REMOTE WAKEUP .................................................... 32
FIGURE 5: SLEEP MODE APPLICATION WITH RI ......................................................................................... 33
FIGURE 6: SLEEP MODE APPLICATION WITHOUT SUSPEND FUNCTION ................................................ 34
FIGURE 7: POWER SUPPLY LIMITS DURING BURST TRANSMISSION ...................................................... 35
FIGURE 8: STAR STRUCTURE OF THE POWER SUPPLY ............................................................................ 36
FIGURE 9: REFERENCE CIRCUIT OF POWER SUPPLY .............................................................................. 36
FIGURE 10: TURN ON THE MODULE USING DRIVING CIRCUIT ................................................................. 37
FIGURE 11: TURN ON THE MODULE USING BUTTON ................................................................................. 38
FIGURE 12: POWER-ON SCENARIO .............................................................................................................. 38
FIGURE 13: POWER-OFF SCENARIO ............................................................................................................ 39
FIGURE 14: REFERENCE CIRCUIT OF RESET_N BY USING DRIVING CIRCUIT ...................................... 40
FIGURE 15: REFERENCE CIRCUIT OF RESET_N BY USING BUTTON ...................................................... 41
FIGURE 16: RESET SCENARIO ...................................................................................................................... 41
FIGURE 17: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH AN 8-PIN (U)SIM CARD CONNECTOR
................................................................................................................................................................... 43
FIGURE 18: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH A 6-PIN (U)SIM CARD CONNECTOR . 43
FIGURE 19: REFERENCE CIRCUIT OF USB INTERFACE ............................................................................ 45
FIGURE 20: REFERENCE CIRCUIT WITH TRANSLATOR CHIP ................................................................... 47
FIGURE 21: REFERENCE CIRCUIT WITH TRANSISTOR CIRCUIT .............................................................. 48
FIGURE 22: PRIMARY MODE TIMING ............................................................................................................ 49
FIGURE 23: AUXILIARY MODE TIMING .......................................................................................................... 49
FIGURE 24: REFERENCE CIRCUIT OF PCM APPLICATION WITH AUDIO CODEC .................................... 50
FIGURE 25: REFERENCE CIRCUIT OF SPI INTERFACE WITH PERIPHERALS ......................................... 51
FIGURE 26: REFERENCE CIRCUIT OF NETWORK STATUS INDICATOR ................................................... 52
FIGURE 27: REFERENCE CIRCUIT OF STATUS ........................................................................................... 53
FIGURE 28: REFERENCE CIRCUIT OF USB_BOOT INTERFACE ................................................................ 55
FIGURE 29: TIMING SEQUENCE FOR ENTERING INTO EMERGENCY DOWNLOAD MODE .................... 56
FIGURE 30: REFERENCE CIRCUIT OF RF ANTENNA INTERFACE ............................................................. 61
FIGURE 31: MICROSTRIP LINE DESIGN ON A 2-LAYER PCB ...................................................................... 62
FIGURE 32: COPLANAR WAVEGUIDE DESIGN ON A 2-LAYER PCB ........................................................... 62
FIGURE 33: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 3 AS REFERENCE GROUND)
................................................................................................................................................................... 62
FIGURE 34: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 4 AS REFERENCE GROUND)
................................................................................................................................................................... 62
FIGURE 35: REFERENCE CIRCUIT OF GNSS ANTENNA ............................................................................. 64
FIGURE 36: DIMENSIONS OF THE U.FL-R-SMT CONNECTOR (UNIT: MM) ................................................ 65
FIGURE 37: MECHANICALS OF U.FL-LP CONNECTORS ............................................................................. 66
FIGURE 38: SPACE FACTOR OF MATED CONNECTOR (UNIT: MM) ........................................................... 66
EG91_Hardware_Design 9 / 93
LTE Module Series
EG91 Hardware Design