Gemalto Cinterion ELS81-US, Hardware Interface Description

Page: 65 / 107

Cinterion
®
ELS81-US Hardware Interface Description
3.2 Power Up/Power Down Scenarios
77

els81-us_hid_v01.004 2017-09-27
Confidential / Preliminary
Page 65 of 107
3.2.5.2 Undervoltage Shutdown
The undervoltage shutdown threshold is the specified minimum supply voltage V
BATT+
given in
Table 2 . When the average supply voltage measured by ELS81-US approaches the undervolt-
age shutdown threshold (i.e., 0.05V offset) the module will send the following URC:
^SBC: Undervoltage Warning
The undervoltage warning is sent only once - until the next time the module is close to the un-
dervoltage shutdown threshold.
If the voltage continues to drop below the specified undervoltage shutdown threshold, the mod-
ule will send the following URC:
^SBC: Undervoltage Shutdown
This alert is sent only once before the module shuts down cleanly without sending any further
messages.
This type of URC does not need to be activated by the user. It will be output automatically when
fault conditions occur.
Note: For battery powered applications it is strongly recommended to implement a BATT+ con-
necting circuit as described in
Section 3.2.1.1 in order to not only be able save power, but also
to restart the module after an undervoltage shutdown where the battery is deeply discharged.
Also note that the undervoltage threshold is calculated for max. 400mV voltage drops during
transmit burst. Power supply sources for external applications should be designed to tolerate
400mV voltage drops without crossing the lower limit of 3.0 V. For external applications oper-
ating at the limit of the allowed tolerance the default undervoltage threshold may be adapted
by subtracting an offset. For details see
[1] : AT^SCFG= "MEShutdown/sVsup/threshold".
3.2.5.3 Overvoltage Shutdown
The overvoltage shutdown threshold is the specified maximum supply voltage V
BATT+
given in
Table 2 . When the average supply voltage measured by ELS81-US approaches the overvolt-
age shutdown threshold (i.e., 0.05V offset) the module will send the following URC:
^SBC: Overvoltage Warning
The overvoltage warning is sent only once - until the next time the module is close to the over-
voltage shutdown threshold.
If the voltage continues to rise above the specified overvoltage shutdown threshold, the module
will send the following URC:
^SBC: Overvoltage Shutdown
This alert is sent only once before the module shuts down cleanly without sending any further
messages.
This type of URC does not need to be activated by the user. It will be output automatically when
fault conditions occur.
Keep in mind that several ELS81-US components are directly linked to BATT+ and, therefore,
the supply voltage remains applied at major parts of ELS81-US. Especially the power amplifier
linked to BATT+
RF
is very sensitive to high voltage and might even be destroyed.