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TMUX1574: About TMUX1574 Spice Model

Takashi Sato
Prodigy 20 points
Part Number: TMUX1574

Hi Team,

I have a question about the Spice model of TMUX1574.

I am simulating TMUX1574 with PSpice for TI.
When VDD voltage = 5V, it works as per the datasheet, but when VDD voltage = 3.3V, it doesn't work.
(Input signal is not output)

The datasheet states that the power supply voltage range of TMUX1574 is 1.5V to 5.5V.
The TMUX1574 should also work at 3.3V.

Is this a typo in the datasheet?
Or is there a problem with the Spice model?

In addition, the Spice model uses the one that comes with PSpice for TI.

Best regards.

  • +1
    TI__Mastermind 23673 points

    Hey Takahashi,

    We're currently out for a US holiday and will get back to you Monday 11/28

    I will quickly note that this isn't a typo in the datasheet and the tmux1574 can definitely support this range. I believe there was a limitation in the way the tmux1574 model was previously created. I'll take a look on Monday and see if I can get you a model that can function at 3V3

    Thanks! 

    Rami

  • 0
    TI__Mastermind 23673 points

    Hey Takashi,

    I took a look at the model itself and it seems this was only designed for 5V so wouldn't be able to support a higher supply voltage. Looks like it was done with an older model layout than we currently have and we have this device in queue to get updated to better support all voltage ranges that the TMUX1574 supports.

    There are a couple of options here. Truthfully, the 5V supply case operates close to the 3.3V supply case so you could just run a 5V supply for simulation purposes and see similar results. This is just due to the internal architecture which gives pretty consistent and flat performance across supply and voltage inputs. Or you could replicate the device with the passive devices model ([FAQ] What if my Analog Switch/Multiplexer is Missing a PSpice Model?) using specs from the datasheet table and figures. You'll find though that the ratings for 3.3V and 5V are extremely similar so I'd advise just using a separate 5V supply on the current PSPICE model, unless there is some issue/reservations with doing so.

    Thanks,
    Rami

  • +1 in reply to Rami Mooti1
    Prodigy 20 points

    Dear Rami,

    I understand the specifications of the SPICE model of TMUX1574.

    Just to be sure, let me confirm just one point.

    Is the operating voltage range of the TMUX1574 (actual device) 1.5V to 5.5V described in the datasheet correct?
    (I want to use TMUX1574 at 1.8V)

    Best regards.

  • 0 in reply to Takashi Sato
    TI__Mastermind 23673 points

    Hey Takahashi,

    This is correct. As the datasheet specifies and as you mentioned, the tmux1574 will be operational with a 1.8V supply. Your I/O voltages can go from 0V to 3.6V when using it as such

    Thanks!

    Rami

  • +1 in reply to Rami Mooti1
    Prodigy 20 points

    Dear Rami

    I understand.

    thank you!

    Best regards.