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ADG408/409 LTSpice Transient Analysis

Question asked by calebreister on Jun 9, 2018
Latest reply on Jun 11, 2018 by calebreister

I've been trying to perform a basic transient analysis within LTSpice using the ADG408 multiplexer, and have been getting very strange results:

  • The output voltage spikes when the address is changed, but the corresponding switch input is not transferred.
  • A substantial amount of current is sometimes drawn at the switch inputs.
  • Changing the enable input seems to have no effect.

I've tried a variety of configurations, and have been unable to get the model to work as expected. Is this a limitation of the model or LTSpice, or am I doing something incorrectly?

 

I've attached the LTSpice schematic and symbol I created, along with a screenshot showing the unexpected behavior. The A2:A0 pins are driven with 3.3V pulse sources configured to produce a 3-bit binary count pattern.

 

 

The ADG409 Spice model produces similar results.

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