SN74CB3Q3253: SN74CB3Q3253

N Maris

Part Number: SN74CB3Q3253

I am considering using a SN74CB3Q3253RGYR mux/demux in a design, but only need to use section 1, I do not need section 2. What are recommended connections for the unused pins in section 2 (A, B1 -B4, I realize 2OEn should be tied to VDD)? Thanks.

over 3 years ago

0 N Maris over 3 years ago

Prodigy 210 points

FWIW, data sheet (pg 10 section 9.2) suggests connecting unused "A" pin either high or low, but does not mention the B pins.

+1 Parker Dodson over 3 years ago

TI__Mastermind 46317 points

Hi N. Maris,

A, B1-B4 - All of these terminated with 50 Ohm Resistors to ground if unused. I am not sure why we put that section in there under 9.2 because generally speaking if its an I/O pin and unused you tie it to ground with a 50 resistor for higher speed applications where reflections are a concern and can typically leave them floating otherwise. This part isn't special and operates with that idea as well .

2/OE - You are correct tie this high to disable that block.

All this information can also be found in our precision lab video on what to do with unused mux pins: https://training.ti.com/ti-precision-labs-switches-and-muxes-can-i-leave-unused-pins-floating

If you have any other questions please let me know!

Best,

Parker Dodson

0 N Maris over 3 years ago in reply to N Maris

Prodigy 210 points

Thanks for the help!

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SN74CB3Q3253: SN74CB3Q3253