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SN74CB3Q3257: SN74CB3Q3257 VSEL voltage, 1.8 V logic support

Part Number: SN74CB3Q3257
Other Parts Discussed in Thread: TMUX1574, SN3257-Q1


We are using the SN74CB3Q3257 (4 channels ,2:1, Multiplexer) in our application.

The supply voltage is 3.3V, so the Vs must >2V to control. But the Vs voltage from MCU now is 1.8V.

Can we add a trido from 3.3V to enhance the drive voltage?

Or can use Vcc=1.8V when the Vin=1.8V?


In addition, do we have device which selected pin voltage is 1.8V compatible.

Vin=1.8V(SPI up to 32MHz)  and Vcc can be 1.8V ,3.3V, 5V



  • Hi Saminah,


    Unfortunately, the SN74CB3Q3257 is not going to be compatible with the change in the application. However we do have alternatives.


    The first is the TMUX1574 is a replacement of the SN74CB3Q3257, and is pin to pin for the PW packages, and supports 1.8V logic signaling. It has a nominal -3dB bandwidth of 2GHz so there shouldn’t be any issue. It can work at a VCC = 1.5V to 5.5V.


    The second is the SN3257-Q1, it is a pin to pin replacement of the SN74CB3Q57; however, it does have a lower current rating ( 30 mA instead of 50mA). It does have 1.8V compatible logic. It can work at VCC = 1.5V to 5.5V and can pass the signal needed.


    If you have any other questions please feel free to reach out to me!

    Best Regards,

    Parker Dodson