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.[1] ADMS can be used to turn Verilog-A compact models[2] into C code. ADMS interpreter parses a Verilog-AMS file to build a data tree.[3] 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.[4]

ADMS is used by the open source SPICE simulator NGSPICE[5] to support a number of compact models. Following models are supported by NGSPICE using ADMS:[6]

  • 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).

References
  1. Sergey Sukharev (24 March 2006). "New enhancements in ADMS and Spectre CMI XML scripts" (PDF). mos-ak.org. Retrieved 9 April 2023.
  2. Transistor model#Models for circuit design .28compact models.29
  3. "Tutorial". Archived from the original on 28 September 2013. Retrieved 9 January 2014.
  4. "Compact device modeling using Verilog-AMS and ADMS" (PDF). Archived from the original (PDF) on 4 March 2016. Retrieved 27 April 2015.
  5. "Ngspice circuit simulator - adms".
  6. "Ngspice circuit simulator - adms and ngspice HOWTO". ngspice.sourceforge.io. Retrieved 9 April 2023.

See also
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