User's Manual

SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R08 Objective Specification System description
Page 74 of 188
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 15 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 in still air conditions
Table 15: Thresholds definition for Smart Temperature Supervisor on the SARA-G340 and SARA-G350 modules
The sensor measures board temperature inside the shields, which can differ from ambient temperature.
1.13.11 AssistNow clients and GNSS integration
Not supported by SARA-G300 and SARA-G310 modules.
For customers using u-blox GNSS receivers, SARA-G340, SARA-G350 and SARA-U2 modules feature embedded
AssistNow clients. AssistNow A-GPS provides better GNSS performance and faster Time-To-First-Fix. The clients
can be enabled and disabled with an AT command (see the u-blox AT Commands Manual [3]).
SARA-G340, SARA-G350 and SARA-U2 modules act as a stand-alone AssistNow client, making AssistNow
available with no additional requirements for resources or software integration on an external host micro
controller. Full access to u-blox positioning receivers is available via the cellular modules, through a dedicated
DDC (I
2
C) interface, while the available GPIOs can handle the positioning chipset / module power-on/off. This
means that the cellular module and the positioning chips and modules can be controlled through a single serial
port from any host processor.