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Design Languages >> Verilog-AMS >> Paramset selection based on temperature
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Message started by ee2 on Jan 13^th, 2015, 11:55am

Title: Paramset selection based on temperature
Post by ee2 on Jan 13^th, 2015, 11:55am

I have a Verilog-A model that uses different paramsets based on the instance parameters (i.e. paramset overloading as described in 6.4.2 of the Verilog-AMS LRM).

Is it possible to do select the paramset based on the simulator temperature ($temperature) rather than an instance parameter?

Or is there a better way in Verilog-A to select parameter values based on simulator temperature?

Thanks.

Title: Re: Paramset selection based on temperature
Post by Geoffrey_Coram on Jan 16^th, 2015, 12:09pm

I haven't seen an example using $temperature, but I don't see any reason that that wouldn't be allowed. The original paramset proposal had the idea that one might pick a model based on a design switch -- eg, if you are doing digital or analog simulation of the block.

Usually, though, the model has its own temperature-update equations, and one specifies parameter values for the nominal temperature (tnom or tref). Sometimes, there will be subcircuit equations involving temperature. I wouldn't expect to need a paramset -- unless you're trying to pick one model for room-temperature operation, and a completely different model for super-cold (superconducting?) or super-hot (industrial) temperatures.

Title: Re: Paramset selection based on temperature
Post by ee2 on Jan 16^th, 2015, 2:19pm

Thanks Geoffrey. As you guessed, I’m doing this for modeling at extreme temperatures.

I was hung up on trying to get the $temperature set as an instance parameter so that it could be used in the selection of the paramset.

After reading your post I revisited the paramset selection criteria and realized I could use a localparam set to $temperature within the paramset and that will be used in the paramset selection. This method is working for me now.

Title: Re: Paramset selection based on temperature
Post by Geoffrey_Coram on Jan 20^th, 2015, 1:30pm

Glad to hear it's working.