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neoflash

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Passive element modeling in Cadence
Nov 23^rd, 2006, 6:40am

Normally, those passive elements will be a w-element, or a touchstone file. They will either be represented by a subckt, or special instance in cadence library.

However, cadence analogLib does not support w-element instance and s-parameter instance. Currently, we manually edit spice netlist and add those passive elements into the circuit.

Any suggestion to make those passive elements could be directly extracted from schematic?

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jbdavid

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Re: Passive element modeling in Cadence
Reply #1 - Dec 8^th, 2006, 11:06pm

s - parameter instances are supporte.. just use an n2port

on top of that you can use the tline, mtline, msline
models, and they even have tools to help you pick the right geomtry for the impedance..

I took the subcircuit model they generated for a shielded 2 wire transmission line, and modified it for arbitrary length,
put it with its own symbol..
I even wrote a verilog-ams model for the block to have the correct delay for the length when I use it in a digital (ie CML ) context..
maybe after the holidays I can write that up..
jbd

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jbdavid
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neoflash Community Fellow Offline Mixed-Signal Designer Posts: 397	Re: Passive element modeling in Cadence Reply #2 - Dec 10^th, 2006, 5:51am any way to use w-element?
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Ken Kundert

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Re: Passive element modeling in Cadence
Reply #3 - Dec 10^th, 2006, 9:20am

If I remember right Spectre does have a component called the 'mtline' that is supposed to be a superset of the 'w-element'. If you applied Spectre to an HSpice netlist containing such a component, it might very well just simulate it without difficulty. If you wanted to use it in a Spectre netlist you would have to use "spectre -h mtline" to help you specify the parameters in Spectre format.

-Ken

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