Ublox TOBY-R2 Series System Integration Manual

Also see for TOBY-R2 Series: User guide

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Ublox TOBY-R2 Series System Integration Manual Manual pdf 81 page image

TOBY-R2 series - System integration manualUBX-16010572 - R10 Design-in Page 81 of 1512.2.3 Generic digital interfaces supply output (V_INT)2.2.3.1 Guidelines for V_INT circuit designTOBY-R2 series provide the V_INT generic digital interfaces 1.8 V supply output, which can be mainlyused 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) Pull-up DDC (I2C) interface signals (see section 2.6.3 for more details) Supply a 1.8 V u-blox 6 or subsequent u-blox GNSS receiver generation (see section 2.6.3 for moredetails) Supply an external device, as an external 1.8 V audio codec (see section 2.7.1 for more details)V_INT supply output pin provides internal short circuit protection to limit start-up current and protectthe device in short circuit situations. No additional external short circuit protection is required.☞ Do not apply loads which might exceed the limit for maximum available current from V_INT supply(see the TOBY-R2 series data sheet [1]) as this can cause malfunctions in internal circuitry.☞ Since the V_INT supply is generated by an internal switching step-down regulator, the V_INTvoltage ripple can range as specified in the TOBY-R2 series data sheet [1]: it is not recommendedto supply sensitive analog circuitry without adequate filtering for digital noise.☞ 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 toJESD22-A114). Higher protection level could be required if the line is externally accessible and itcan 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 ofan accessible test point directly connected to the V_INT pin.2.2.3.2 Guidelines for V_INT layout designV_INT supply output is generated by an integrated switching step-down converter. Because of this, itcan be a source of noise: avoid coupling with sensitive signals.