User's Manual

XT55/56 Hardware Interface Description
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XT55/56_hd_v02.06a Page 87 of 125 17.12.2004
6 Electrical, reliability and radio characteristics
6.1 Absolute maximum ratings
Absolute maximum ratings for supply voltage and voltages on digital and analog pins of
XT55/56 are listed in Table 24. Exceeding these values will cause permanent damage to
XT55/56.
Table 24: Absolute maximum ratings (GSM part)
Parameter Min Max Unit
Voltage GSM_BATT+ -0.3 4.8 V
Voltage at digital pins -0.3 3.3 V
Voltage at analog pins -0.3 3.0 V
Voltage at digital / analog pins in POWER DOWN mode -0.25 +0.25 V
Voltage at GSM_POWER pin 15 V
Voltage at GSM_CHARGE pin 15 V
Differential load resistance between EPNx and EPPx 15
Ω
Table 25: Absolute maximum rating (GPS part)
Parameter Min Max Unit
Voltage at GPS_VCC -0.3 3.46 V
Current at GPS_VCC_RF 25 mA
6.2 Operating temperatures
Test conditions were specified in accordance with IEC 60068-2 (still air). The values stated
below are in compliance with GSM recommendation TS 51.010-01.
Table 26: Operating temperatures
Parameter Min Typ Max Unit
Ambient temperature (according to GSM 11.10) -20 25 55 °C
Restricted operation
*)
-25 to -20 55 to 70
***
°C
Automatic shutdown
XT55/56 board temperature
Battery temperature
-29
-18
>70
**
>60
°C
°C
Charging temperature (software controlled fast charging) 0 +45 °C
*)
XT55/56 works, but deviations from the GSM specification may occur.
**)
XT55/56 has the automatic shutdown set to 70°C at PCL 5 (GSM 900) GPRS class 8. This
prevents permanent damage to components on the board. Consider the ratio of output power,