SMALL SIGNAL FET/HEMT MODELING
CAMFET, part of the MMICAD suite of software solutions, expands MMICAD's capabilities to assist the designer in using measured vector network analyzer data in simulation and modeling. CAMFET is designed to integrate seamlessly with the MMICAD Linear Simulator Version 3, enhancing the designer's capability to incorporate measured data into a simulation, improving accuracy, productivity and cost-effectiveness. It can also be operated stand-alone.
CAT Capability Enhancements:
- Two bias controls can be used. For example, S-parameters which span the complete I-V characteristics of a transistor can be measured from the network analyzer. This data can be used directly in a MMICAD simulation to determine the influence of transistor bias variation on amplifier performance.
- Stimulus/Response measurements can be made. Measurements can be made as a function of other control variables. For example, a family of I-V characteristics for a transistor can be acquired and displayed, or the temperature dependence of the S-parameters of a varactor diode can be measured.
Modeling Enhancements:
- Fit 6 types of transistor small-signal equivalent circuits to measured data.
- A 16-element model including gate and drain pad capacitances and feedback resistors, but exclusing the gate extrinsic resistance (Ri).
- A 15-element model including gate and drain pad capacitances and Ri.
- A full 13-element model.
- Two 12-element models where either Ri or Tau are excluded.
- An 11-element model where both Ri and Tau are excluded.
Precise small-signal fitting is ensured by optimizing the small-signal equivalent circuit components over independently defined frequency ranges and weighting functions. Special care ensures accurate extraction of the extrinsic transistor parasitics. Unlike other optimization techniques which produce degenerate multiple solutions, the extrinsic resistors (Rs, Rd and Rg) are independently varied to obtain a global minimum solution. At any drain bias, the individual small-signal equivalent circuits for each gate bias point are collected into tabular data suitable for use in MMICAD. This results in a compact description of the linear behavior of the transistor as a function of bias, which can be used in MMICAD to predict bias-dependent circuit behavior.
- Develop models for components on Stimulus/Response measurements. The MMICAD Version 3 simulator can directly read either bias-dependent tabular data or S-parameter data collected during data acquisition for use in simulation. This allows MMICAD to act as a powerful modeling tool to develop bias-dependent models for components based on stimulus/response measurements.
- Power Supply Support. Interfaces with a broad range of power supplies including:
Keithley model 236 and HP models, 4143, 4145, 3632 and 6622A.
Pricing
Contact
sales@optotek.com.
