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Design Languages >> Verilog-AMS >> use of small signal resources is not supported?
https://designers-guide.org/forum/YaBB.pl?num=1220962591

Message started by nus_lin on Sep 9^th, 2008, 5:16am

Title: use of small signal resources is not supported?
Post by nus_lin on Sep 9^th, 2008, 5:16am

hi, guys. i copied almost the same code from "the designer's guide to verilog-ams", by Ken. Kundert, our "god father". but unfortunately i got this error message: "use of small signal resources is not supported?" the code is given below:

`include "constants.vams"
`include "disciplines.vams"

module resport(p,n);
parameter real r=1 from (0:inf);
parameter real dc=0;
parameter real mag=1;
inout p,n;
electrical p,n;

analog begin
V(p,n)<+r*I(p,n)+2*dc;
V(p,n)<+2*ac_stim("ac",mag,0);
V(p,n)<+white_noise(4*`P_K*$temperature,"thermal");
end
endmodule

Title: Re: use of small signal resources is not supported?
Post by Geoffrey_Coram on Sep 9^th, 2008, 5:32am

What simulator is that? small-signal sources (ac_stim, white_noise) are pretty basic to any Spice-like simulator, so I'm surprised there's one that supports Verilog-A but not these.

Of course, if you're using a timing (aka fast-spice) simulator, it probably only supports transient analysis, no small-signal.

Title: Re: use of small signal resources is not supported?
Post by nus_lin on Sep 9^th, 2008, 5:59am

thank you for the reply. i used the cadence design kits for AMS0.35.

Title: Re: use of small signal resources is not supported?
Post by nus_lin on Sep 9^th, 2008, 6:02am

Error found by spectre during SpectreHDL compile.

file: ***********
nonrecoverable error: use of small signal resources is not supported
Exiting AHDL compilation.

Title: Re: use of small signal resources is not supported?
Post by Ken Kundert on Sep 9^th, 2008, 10:28am

It's odd that the error message says "SpectreHDL". Are you sure you are including it as a verilog-A file?

-Ken

Title: Re: use of small signal resources is not supported?
Post by nus_lin on Sep 10^th, 2008, 12:19am

hi, god father, i have no idea about spectraHDL, but i found a way to solve the "small signal resources" problem.

by changing V(p,n)<+2*ac_stim("ac",mag,0); to V(p,n)<+ac_stim("ac",2*mag,0);