u-blox SARA-R4 Series System Integration Manual

Contents

SARA-R4 series - System Integration ManualUBX-16029218 - R06 Design-inPage 46 of 1022.2.2 Generic digital interfaces supply output (V_INT)2.2.2.1 Guidelines for V_INT circuit designSARA-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 insections 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 devicesDo not apply loads which might exceed the limit for maximum available current from V_INT supply (seethe 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 bymounting 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 ofSARA-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 anaccessible test point directly connected to the V_INT pin.