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MAX3160E FAST-MODE pin termination

Category: Datasheet/Specs
Product Number: MAX3160E

The MAX3160E FAST-MODE operation describes the pin as asserted or unasserted.  In this context is unasserted the same as GND / De-assertion?  I am reviewing schematics where they left this pin floating and I want to confirm the terminology unasserted doesn't mean floating here.  I see no mention of internal pull-up/down termination on this pin.  I am assuming this pin needs to be pulled to ground or VCC.  

  • Quoted portion of datasheet

    "Fast-Mode Operation The FAST control input is used to select the slew-rate limiting of the RS-232 transmitters and the RS-485/ RS-422 drivers. With FAST unasserted, the RS-232 transmitters and the RS-485/RS-422 driver are slew-rate limited to reduce EMI. RS-232 data rates up to 1Mbps and RS-485/RS-422 data rates up to 10Mbps are possible when FAST is asserted. FAST can be changed during operation without interrupting data communications."

  • Hello,

    Thank you for your question!

    You are correct - FAST is asserted when connected high (> 2.4V) and unasserted when connected low (<0.8V).  So, yes, it would be considered as unasserted when connected to ground.

    There is no internal pull-up or pull-down on the FAST pin. You are correct that the pin needs to be connected high (VCC) or low (GND) to enable/disable fast mode.

    Best,

    Shasta