SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R26
System description
Page 88 of 217
Threshold definitions
When the module application operates at extreme temperatures with Smart Temperature Supervisor enabled,
the user should note that outside the valid temperature range the device automatically shuts down as described
above.
The input for the algorithm is always the temperature measured within the cellular module (Ti, internal). This
value can be higher than the working ambient temperature (Ta, ambient), since (for example) during
transmission at maximum power a significant fraction of DC input power is dissipated as heat. This behavior is
partially compensated by the definition of the upper shutdown threshold (t
+2
) that is slightly higher than the
declared environmental temperature limit.
Table 22 defines the temperature thresholds for SARA-G340 and SARA-G350 modules.
Symbol
Parameter
Temperature
Remarks
t
-2
Low temperature shutdown
–40 °C
Equal to the absolute minimum temperature rating for the cellular
module (the lower limit of the extended temperature range)
t
-1
Low temperature warning
–30 °C
10 °C above t
-2
t
+1
High temperature warning
+85 °C
10 °C below t
+2
. The higher warning area for upper range ensures
that any countermeasures used to limit the thermal heating will
become effective, even considering some thermal inertia of the
complete assembly.
t
+2
High temperature shutdown
+95 °C
Equal to the internal temperature Ti measured in the worst case
operating condition at typical supply voltage when the ambient
temperature Ta in the reference setup (*) equals the absolute
maximum temperature rating (upper limit of the extended
temperature range)
(*) SARA-G340 / SARA-G350 module mounted on a 79 x 62 x 1.41 mm 4-Layers PCB with a high coverage of copper
Table 22: Thresholds definition for Smart Temperature Supervisor on the SARA-G340 and SARA-G350 modules
Table 23 defines the temperature thresholds for SARA-U2 modules.
Symbol
Parameter
Temperature
Remarks
t
-2
Low temperature shutdown
–40 °C
Equal to the absolute minimum temperature rating for the cellular
module (the lower limit of the extended temperature range)
t
-1
Low temperature warning
–30 °C
10 °C above t
-2
t
+1
High temperature warning
+77 °C
20 °C below t
+2
. The higher warning area for upper range ensures
that any countermeasures used to limit the thermal heating will
become effective, even considering some thermal inertia of the
complete assembly.
t
+2
High temperature shutdown
+97 °C
Equal to the internal temperature Ti measured in the worst case
operating condition at typical supply voltage when the ambient
temperature Ta in the reference setup (*) equals the absolute
maximum temperature rating (upper limit of the extended
temperature range)
(*) SARA-U2 module mounted on a 79 x 62 x 1.41 mm 4-Layers PCB with a high coverage of copper
Table 23: Thresholds definition for Smart Temperature Supervisor on the SARA-U2 modules
The sensor measures board temperature inside the shields, which can differ from ambient temperature.
