u-blox LARA-R2 series System Integration Manual

Also see for LARA-R2 series: System integration manual

Contents

u-blox LARA-R2 series System Integration Manual Manual pdf 84 page image

LARA-R2 series - System Integration ManualUBX-16010573 - R02 Objective Specification Design-inPage 84 of 1482.3.3 Module / host configuration selection2.3.3.1 Guidelines for HOST_SELECT circuit designSelection of module / host configuration over HOST_SELECT is not supported by “02” product versions.LARA-R2 series modules include one pin (HOST_SELECT) to select the module / host application processorconfiguration: the pin is available to select, enable, connect, disconnect and subsequently re-connect the HSIC(USB High-Speed Inter-Chip) interface.LARA-R2 series Data Sheet [1] describes the detailed electrical characteristics of the HOST_SELECT pin.Further guidelines for HOST_SELECT pin circuit design will be described in detail in a successive release ofthe System Integration Manual.Do not apply voltage to HOST_SELECT pin before the switch-on of its supply source (V_INT), to avoidlatch-up of circuits and allow a proper boot of the module. If the external signal connected to the cellularmodule cannot be tri-stated or set low, insert a multi channel digital switch (e.g. TI SN74CB3Q16244,TS5A3159, or TS5A63157) between the two-circuit connections and set to high impedance before V_INTswitch-on.ESD sensitivity rating of the HOST_SELECT pin is 1 kV (HBM as per JESD22-A114). Higher protection levelcould be required if the lines are externally accessible and it can be achieved by mounting an ESDprotection (e.g. EPCOS CA05P4S14THSG varistor array) close to accessible pointsIf the HOST_SELECT pin is not used, they can be left unconnected on the application board.2.3.3.2 Guidelines for HOST_SELECT layout designThe pin for the selection of the module / host application processor configuration (HOST_SELECT) is generallynot critical for layout.