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TMUX1072: Spice model do not work if a negative voltage is applied to GND!

Peter Soerensen
Prodigy 60 points
Part Number: TMUX1072
Other Parts Discussed in Thread: CD74HCT4052

Tool/software:

TMUX1072 spice model does not work if GND is connected to a negative voltage instead of GND.
Thats makes is very hard to simulate a PGA circuit with input referend to GND  and opamps, TMUX1072 using dual supply!
The workaround I have is to change -Vcc, GND +Vdd into GND, V(-(-Vcc), V(-(-Vcc)+Vdd) but the properbility that the simulated circuit is NOT the same as the actual HW becomes much higher.

  • 0
    TI__Mastermind 31123 points

    Hi Peter,

    TMUX1072 is a single sided device so I think that limitation makes sense. Everything in the model is likely referenced to GND so if you shift ground some of the timing gets thrown off. If you want to use TMUX1072 but ground shift it, I'd recommend getting it on a breakoutboard and verifying it behaves as you intend it to. 
    Otherwise, a dual supply device may be a better fit. There aren't a whole lot of options for 2ch 2:1 low voltage dual supplies so you may need to move up to 4:1's like the CD74HCT4052.

    Thanks,
    Rami