Specifications

TC35 / TC37 Hardware Interface Description
TC35_37_HD_02_V03.10 - Released Page 36 of 92 21.12.2001
Table 9: Dependency on ambient temperature
Reason of shutdown Ambient Temperature
High temperature T
amb
> 70°C
Low temperature T
amb
<-25°C
High temperature with battery pack T
amb,Akku
> 60°C
Low temperature with battery pack T
amb,Akku
<-15°C
Shutdown in the event of undervoltage
The software constantly monitors the applied voltage to check that the voltage is sufficient to
set up a call. When the supply decreases to V
batt+
< 3.3V, the following URC will be
presented:
^SBC: Undervoltage
The message will be reported, for example, when you attempt to set up a call while the
voltage is close to the critical limit and further power loss is caused during the transmit burst.
To remind you that the battery needs to be charged soon the URC appears, in SLEEP or
IDLE mode, several times before the module switches off. In this case, the battery capacity
is still sufficient to set up a short call. If undervoltage occurs during a call (transmit burst), the
module turns off immediately after the URC has been presented.
To enable or disable the URC use the AT^SBC command. The URC will be enabled only
when you enter the write command and specify the power consumption of your GSM
application. Step by step instructions are provided in the "TC3x35 AT Command Set".
Note: The undervoltage protection is only efficient in battery operated applications where an
NTC is present. If no NTC is detected (no NTC connected to the ACCU_TEMP)
undervoltage URCs will be not be generated. In this case, the module turns off without
prior alert.
Shutdown in the event of overvoltage
Overvoltage protection is implemented in the PSU-ASIC. If the supply voltage raises to
V
batt+
> 5.8V TC35 or TC37 switches off automatically. In contrast to undervoltage shutdown
• there is no URC function available
• and the module turns off immediately, i.e. loss of data cannot be avoided.