Driving an Input to High Impedence in Hspice

[Sreekumar]

Hi,

I want to put an input of a gate to high impedence state (tristate or
basically disconnect from vdd or gnd) at some point of time during the
hspice simulation. I tried the manuals of Hspice and couldnt find
information regarding this. I would be greatful if anyone could
provide any help in this regard.

Thanks

Sreekumar

 

[Kevin Aylward]

Sreekumar wrote:

Hi,

I want to put an input of a gate to high impedence state (tristate or
basically disconnect from vdd or gnd) at some point of time during the
hspice simulation. I tried the manuals of Hspice and couldnt find
information regarding this. I would be greatful if anyone could
provide any help in this regard.

Construct a discrete gate/buffer with transistors!

Note that floating an output often results in simulation failure.
Your'll probably have to have a large value resister to a dc node at the
tri-state output.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[Jamie]

you can if you don't mind inverting the input.
place a simple NPN switching transitor there.
C to your existing input, E to another Gate output
to put the emiter to ground and the base will be your input.
of you can use a Tri-State buffer..


Sreekumar wrote:

Hi,

I want to put an input of a gate to high impedence state (tristate or
basically disconnect from vdd or gnd) at some point of time during the
hspice simulation. I tried the manuals of Hspice and couldnt find
information regarding this. I would be greatful if anyone could
provide any help in this regard.

Thanks

Sreekumar