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TMUX1575: floating unused SxB pins

Lior Avrahami
Prodigy 10 points
Part Number: TMUX1575

I'm using 2x TMUX1575YCJ in a development board.

Their used between:

SPI/QSPI flash, which is connected to Dx ports,

A host, which is connected to SxA ports,

and, a header, which is connected to SxB ports.

Some of the SxB pins are unused and are floating while their corresponding SxA ports are connected to the host (see attached scheme).

Reason for them kept float is since grounding them would affect the Flash.

I wanted to make sure leaving these pins float won't affect the MUX behavior in different states nor cause damage over time.

  • 0
    TI__Mastermind 35618 points

    Hey Lior,

    Typically we recommend terminating unused channels with a 50ohm or equivalent matching resistor to ground when you start getting into higher frequencies. This is more to help with noise and reflections. Since you're doing SPI/QSPI I would expect your frequencies to be <100MHz so you're probably fine floating these unused channels. The mux behavior will have no impact whether these are grounded or floated either way.

    Thanks,
    Rami