SARA-R4 series - System Integration Manual
UBX-16029218 - R06
Design-in
Page 46 of 102
2.2.2
Generic digital interfaces supply output (V_INT)
2.2.2.1
Guidelines for V_INT circuit design
SARA-R4 series provide the
V_INT
generic digital interfaces 1.8 V supply output, which can be mainly used to:
Indicate when the module is switched on and it is not in the deep sleep power saving mode (as described in
sections 1.6.1, 1.6.2)
Pull-up SIM detection signal (see section 2.5 for more details)
Supply voltage translators to connect 1.8 V module generic digital interfaces to 3.0 V devices (e.g. see 2.6.1)
Enable external voltage regulators providing supply for external devices
Do not apply loads which might exceed the limit for maximum available current from
V_INT
supply (see
the
SARA-R4 series
Data Sheet
[1]) as this can cause malfunctions in internal circuitry.
V_INT
can only be used as an output: do not connect any external supply source on
V_INT
.
ESD sensitivity rating of the
V_INT
supply pin is 1 kV (Human Body Model according to JESD22-A114).
Higher protection level could be required if the line is externally accessible and it can be achieved by
mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible point.
It is recommended to monitor the
V_INT
pin to sense the end of the internal switch-off sequence of
SARA-R4 series modules:
VCC
supply can be removed only after
V_INT
goes low.
It is recommended to provide direct access to the
V_INT
pin on the application board by means of an
accessible test point directly connected to the
V_INT
pin.
