Specifications

XT55 Hardware Interface Description
Confidential / Preliminary
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XT55_hd_v00.02 Page 6 of 116 17.03.2004
Figures
Figure 1: Block diagram of serial interface concept..............................................................23
Figure 2: Block diagram of XT55 for SiRF Demo application................................................24
Figure 3: Block diagram of XT55 with AVL or TCP/IP application (optional).........................24
Figure 4: Power supply limits during transmit burst ..............................................................28
Figure 5: Power-on by ignition signal....................................................................................30
Figure 6: Timing of power-on process if GSM_VDDLP is not used ......................................31
Figure 7: Timing of power-on process if GSM_VDDLP is fed from external source..............31
Figure 8: Deactivating GSM engine by GSM_EMERGOFF signal........................................35
Figure 9: Schematic of approved charging transistor, trickle charging and ESD protection..40
Figure 10: Battery pack circuit diagram ................................................................................42
Figure 11: Charging process ................................................................................................44
Figure 12: Timing of CTS signal (example for a 2.12 s paging cycle)...................................49
Figure 13: Beginning of power saving if CFUN=5 or 7..........................................................49
Figure 14: RTC supply from capacitor..................................................................................53
Figure 15: RTC supply from rechargeable battery................................................................53
Figure 16: RTC supply from non-chargeable battery............................................................53
Figure 17: Audio block diagram............................................................................................56
Figure 18: Schematic of microphone inputs .........................................................................57
Figure 19: DAI timing on transmit path .................................................................................59
Figure 20: DAI timing on receive path ..................................................................................59
Figure 21: SIM card holder of DSB45 Support Box ..............................................................62
Figure 22: Pin numbers of Molex SIM card holder on DSB45 Support Box ..........................62
Figure 23: GSM_SYNC signal during transmit burst.............................................................64
Figure 24: LED Circuit (Example).........................................................................................65
Figure 25: Incoming voice call..............................................................................................66
Figure 26: Incoming data call ...............................................................................................66
Figure 27: URC transmission ...............................................................................................66
Figure 28: Theory of operation .............................................................................................68
Figure 29: Example for current in Trickle Power mode.........................................................71
Figure 30: Current comparison between Trickle Power and Push-to Fix mode ....................72
Figure 31: Example of LED circuit ........................................................................................75
Figure 32: Receiver architecture of the GPS receiver...........................................................75
Figure 33: U.FL-R-SMT connector .......................................................................................78
Figure 34: Antenna pad and GND plane ..............................................................................78
Figure 35: Never use antenna connector and antenna pad at the same time.......................79
Figure 36: Restricted area around antenna pad ...................................................................79
Figure 37: GPS antenna connector (U.FL-R-SMT connector) ..............................................80
Figure 38: Mechanical dimensions of U.FL-R-SMT connector..............................................81
Figure 39: U.FL-R-SMT connector with U.FL-LP-040 plug ...................................................82
Figure 40: U.FL-R-SMT connector with U.FL-LP-066 plug ...................................................82
Figure 41: Specifications of U.FL-LP-(V)-040(01) plug.........................................................83
Figure 42: Pin assignment (top view on XT55).....................................................................86
Figure 43: Typical current consumption vs. return loss in EGSM 900 network .....................94
Figure 44: Typical current consumption vs. return loss in GSM 1800 network......................95
Figure 45: Typical current consumption vs. return loss in GSM 1900 network......................95
Figure 46: Peak current consumption during transmit burst in EGSM 900 network ..............96
Figure 47: Peak current consumption during transmit burst in GSM 1800 network ..............96
Figure 48: Peak current consumption during transmit burst in GSM 1900 network ..............97
Figure 49: Typical current consumption vs. return loss.........................................................98
Figure 50: AT audio programming model ...........................................................................100
Figure 51: XT55 – top view ................................................................................................107