Specifications

XT55 Hardware Interface Description
Confidential / Preliminary
s
mo b i l e
XT55_hd_v00.02 Page 85 of 116 17.03.2004
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 are listed in Table 24. Exceeding these values will cause permanent damage to XT55.
Table 24: Absolute maximum ratings (GSM/GPRS 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
W
Table 25: Absolute maximum rating (GPS part)
Parameter Min Max Unit
Voltage at GPS_VCC 3.14 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 board temperature
Battery temperature
-29
-18
>70
**)
>60
°C
°C
Charging temperature (software controlled fast charging) 0 +45 °C
*)
XT55 works, but deviations from the GSM specification may occur.
**)
XT55 has the automatic shutdown set to 70°C at power class 5 (GSM900) GPRS class 8. This
prevents permanent damage to components on the board. Consider the ratio of output power,
supply voltage and operating temperature: To achieve T
amb max
= 70°C and, for example, GSM
900 PCL5 the supply voltage must not be higher than 4.2V.