The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Modeling >> Behavioral Models >> Verilog A models, Convergence
https://designers-guide.org/forum/YaBB.pl?num=1494081513

Message started by balshoy on May 6^th, 2017, 7:38am

Title: Verilog A models, Convergence
Post by balshoy on May 6^th, 2017, 7:38am

Hi

I am developing Verilog A model for an emerging device. That VerilogA model will be instantiated within an .scs file to run spectre simulations. I have a couple of questions regarding that:

1) As far as I know, spice-like simulators (LTspice, spectre, eldo..etc) have some hard coded models for some elements. Numerical solutions for circuits with such elements are well documented and the methods are known. But, when I use a verilogA model to describe a device, does spectre translate it first to a network of such elements and then solves (something like synthesis in digital) or it operates on the verilogA equations right away?

2)do the algorithms that apply to spice models (eg. NR) also apply to verilogA models?

Thanks

Title: Re: Verilog A models, Convergence
Post by Ken Kundert on May 6^th, 2017, 4:36pm

1. The Verilog-A equations are evaluated directly.

2. Yes. The equations from all components, whether built-in or described with Verilog-A, are combined and solved simultaneously using the conventional SPICE algorithms (conversion to difference equations, Newton Raphson, sparse matrix techniques).

-Ken

Title: Re: Verilog A models, Convergence
Post by balshoy on May 7^th, 2017, 5:44am

Thanks Ken.