User's Manual

SARA-R4 series - System Integration Manual
UBX-16029218 - R03 Design-in
Page 41 of 94
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 (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 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.