Quectel EG21-G, Hardware Design

Page: 8 / 96

LTE Module Series
EG21-G Hardware Design
EG21-G_Hardware_Design 7 / 100
Figure Index
FIGURE 1: FUNCTIONAL DIAGRAM ............................................................................................................... 15
FIGURE 2: PIN ASSIGNMENT (TOP VIEW) .................................................................................................... 17
FIGURE 3: SLEEP MODE APPLICATION VIA UART ....................................................................................... 28
FIGURE 4: SLEEP MODE APPLICATION WITH USB REMOTE WAKEUP .................................................... 29
FIGURE 5: SLEEP MODE APPLICATION WITH RI ......................................................................................... 30
FIGURE 6: SLEEP MODE APPLICATION WITHOUT SUSPENSION FUNCTION .......................................... 30
FIGURE 7: POWER SUPPLY LIMITS DURING BURST TRANSMISSION ...................................................... 32
FIGURE 8: STAR STRUCTURE OF THE POWER SUPPLY ............................................................................ 33
FIGURE 9: REFERENCE CIRCUIT OF POWER SUPPLY .............................................................................. 33
FIGURE 10: TURN ON THE MODULE BY USING DRIVING CIRCUIT ........................................................... 34
FIGURE 11: TURN ON THE MODULE BY USING KEYSTROKE .................................................................... 35
FIGURE 12: POWER-ON SCENARIO OF MODULE ....................................................................................... 35
FIGURE 13: POWER-OFF SCENARIO OF MODULE ...................................................................................... 36
FIGURE 14: REFERENCE CIRCUIT OF RESET_N BY USING DRIVING CIRCUIT ...................................... 37
FIGURE 15: REFERENCE CIRCUIT OF RESET_N BY USING BUTTON ...................................................... 37
FIGURE 16: TIMING OF RESETTING MODULE ............................................................................................. 38
FIGURE 17: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH AN 8-PIN (U)SIM CARD CONNECTOR
...................................................................................................................................................................
39
FIGURE 18: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH A 6-PIN (U)SIM CARD CONNECTOR . 39
FIGURE 19: REFERENCE CIRCUIT OF USB APPLICATION ......................................................................... 41
FIGURE 20: REFERENCE CIRCUIT WITH TRANSLATOR CHIP ................................................................... 43
FIGURE 21: REFERENCE CIRCUIT WITH TRANSISTOR CIRCUIT .............................................................. 44
FIGURE 22: PRIMARY MODE TIMING ............................................................................................................ 45
FIGURE 23: AUXILIARY MODE TIMING .......................................................................................................... 45
FIGURE 24: REFERENCE CIRCUIT OF PCM APPLICATION WITH AUDIO CODEC .................................... 46
FIGURE 25: REFERENCE CIRCUIT OF SD CARD ......................................................................................... 47
FIGURE 29: REFERENCE CIRCUIT OF THE NETWORK INDICATOR .......................................................... 50
FIGURE 30: REFERENCE CIRCUITS OF STATUS ......................................................................................... 51
FIGURE 31: REFERENCE CIRCUIT OF USB_BOOT INTERFACE ................................................................ 52
FIGURE 32: TIMING SEQUENCE FOR ENTERING INTO EMERGENCY DOWNLOAD MODE .................... 53
FIGURE 32: REFERENCE CIRCUIT OF RF ANTENNA INTERFACE ............................................................. 58
FIGURE 33: MICROSTRIP DESIGN ON A 2-LAYER PCB ............................................................................... 59
FIGURE 34: COPLANAR WAVEGUIDE DESIGN ON A 2-LAYER PCB ........................................................... 59
FIGURE 35: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 3 AS REFERENCE GROUND)
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59
FIGURE 36: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 4 AS REFERENCE GROUND)
...................................................................................................................................................................
60
FIGURE 37: REFERENCE CIRCUIT OF GNSS ANTENNA ............................................................................. 61
FIGURE 38: DIMENSIONS OF THE U.FL-R-SMT CONNECTOR (UNIT: MM) ................................................ 63
FIGURE 39: MECHANICALS OF U.FL-LP CONNECTORS ............................................................................. 63
FIGURE 40: SPACE FACTOR OF MATED CONNECTOR (UNIT: MM) ........................................................... 64