how to simulate Digital and Analog circuit in Cadence

how to simulate Digital and Analog circuit in Cadence

Post by ykjin » Mon, 21 Apr 2008 18:19:47

Hi,could someone kindly help me with the simulation for Digital and Analog
circuits simutanously in Cadence enviroment,because the digital circuit and
analog circuit have to be integrated working together . I have finished
following steps:
1. wrote verilog code and synthesized by DC and auto P&R in Astro
2. dupm verilog netlist from Astro and imported into cadence to generate a
schematic/symbol. Imported layout gds file and passed the LVS/DRC by
3. Added the above imported digital symbol view into another analog
transistor level schematic.
I use Analog Environment Spectre to simulate the digital/analog combined
circuit, but there are errors and failed to run.
Could someone kindly tell me how to configure the Analog Environment spectre
for above simulation?

Thank you very much in advance.

how to simulate Digital and Analog circuit in Cadence

Post by Riad KACE » Tue, 22 Apr 2008 09:20:41

Hi Fred,

VIRTUOSO AMS DESIGNER SIMULATOR is a good solution for you.
AMS designer allows you simulating Mixed-signal designs, it features
the following things.
. 2 Analog solvers : Spectre and Ultrasim that. You can switch back
and forth between them depending on the accuray/speed you want to
. ncverilog tools for digital simulation (ncvlog, ncelab, ncsim ....)

You can use AMS designer in 2 models:

1. The Hierarchy Editor (HED) user mode, that's the one I'm using and
the one I prefer. I think Cadence recommands this one as well but not
sure. Andrew may help on this.
2. The ADE use model. You just run your simulation form the Analog
Design Environment, the same as you do for Spectre but choosing ''ams
this time.

Running AMS designers is a quite straight forward step. You just need
some specific files (cds.lib, hdl.var), a connect lib to bridge the
analog/digital signals and your design.
Well, the best way for you is to give a look to the folowing documents
in your Cadence MMSIM stream :
1. Virtuoso AMS Environment User Guide (amsenvug.pdf)
2. AMS Designer Simulator User Guide (amssimug.pdf)

The former comes with a very nice chapter (2) Quick-Start Tutorial, I
would advice to start with. The tutirial goes through an example
available in your install dir.

I think you've got the main bricks there, jst do it yourself now !

I'm just wondering if you need an extra license/tokens to run AMS, my
little memory does not catch it ... I'm sorry I'm lacking this but
other chaps will help.
Anyway, If you havn't got AMS to run and you want to convince your
boss to get it, just link him to the following document. It's well
made ... with nice colors ;-)

Good luck !


PS: Other EDA vendors support AMS tools


how to simulate Digital and Analog circuit in Cadence

Post by ykjin » Tue, 22 Apr 2008 22:04:40

Hi, Riad

Thank you very much for your kindly help and advice.


??????: XXXX@XXXXX.COM ...