ADMS
# ADMS

Automatic Device Model Synthesizer (ADMS) is public domain software used in the semiconductor industry to translate Verilog-A models into C-models which can be directly read by a number of SPICE simulators, including Spectre Circuit Simulator, Ngspice and HSpice.

## Overview

ADMS stands for Automatic Device Model Synthesizer. ADMS can be used to turn Verilog-A compact models into C code. ADMS interpreter parses a Verilog-AMS file to build a data tree. XML filters are applied on the tree to generate the output files.

ADMS aims to reduce the effort of circuit simulator developers to integrate device models - at the same time, it provides the option to compact model developers to use the vendor-neutral language Verilog-A for model definition, improving robustness and maintainability.

ADMS is used by the open source SPICE simulator NGSPICE to support a number of compact models. Following models are supported by NGSPICE using ADMS:

* MOS EKV (LEVEL=44)
* MOS PSP102 (LEVEL=45)
* BJT Mextram 504 (LEVEL=6)
* BJT Hicum0 (LEVEL=7)
* BJT Hicum2 (LEVEL=8)

## Limitations

ADMS only parses a subset of Verilog-A, and not all statements are supported by all XML filters. Specifically, current controlled voltage sources are not supported in most filters targeting SPICE simulators:

* V(..) <+ I(..) // does not work with NGSPICE

Instead, this needs to be represented as a conductance expression (and not impedance).

i.e. I(..) <+ V(..)

* I (..) probes do not work with NGSPICE

Some other language constructions need to be supported in the filter as well

* for loop,
* case statement.

Many language features are hard to support with ADMS filters

* laplace_transform,
* idt,
* switching branches.

Important aspects of code generation are close to impossible with ADMS

* dataflow analysis
* code optimisation,

and

* ADMS is extremely slow (which can be seen on slightly larger models).
