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TS3A27518E: Unused pin connections

Kenji Ohno1
Genius 5095 points
Part Number: TS3A27518E

Hi Team,

I found the following in the datasheet about connecting unused pins.

”TI recommends connecting unused pins to the ground through a 50-ohm resistor".

If I use the recommended treatment for NC6 and NO6 pins, do I need to use the same treatment for COM6 pins?

I want to reduce the current consumption, so can I leave the COM6 pin floating?

Best Regards,

Kenji

  • 0
    TI__Mastermind 28028 points

    Kenji,

    The current consumption due to unused pins will be more dependent on the whether you leave the state of the digital control pins (INx) floating or not. The 50-ohm resistor on the unused signal paths is to prevent reflection back into the device. The unused floating pins will also behave as antennas picking up any unwanted signal. Tying them to ground via a 50 ohm resistor gives somewhere for those energies to dissipate.
    With regards to this specific example, it would depend if you're intending to use the En\ pin or not. Using the logic for the device, you'll always be connected COM6 to NO or NC when EN\ is Low. So you'll give a path to GND when tying only the NO/NC paths and the COM wouldn't really be necessary. However, if you plan on using the En\ pin in your application then it's recommended to tie that to GND as well as it will also be floating in this state.

    Thanks,
    Rami