NXP Compact Models

In this Topic ShowHide

Introduction

SIMetrix supports a range of device models developed by NXP Semiconductor.

This supersedes the old Philips compact models (PCM) interface, however, the older devices are still available if needed. Versions of devices that are available through both interfaces (e.g MOS 9.03) will now default to the SIMKIT interface but the old version is still available by selecting a different level number. PCM devices do not support multi-core execution and so usually the Simkit versions will run faster.

The table below shows the models available. Model statements should be in the form:

E.g.

defines a MOS 9 nmos device.

To instantiate the device line must start with the letter as defined in the Device Letter column in the table below. The number of nodes must be within the range specified in the table.

SIMKIT Devices

The following table shows all available SIMKIT NXP models

Notes on SIMKIT Models

Binned Models

Binned models are not yet integrated with the library binning system. So, to use the binning features of binned models, you will need to manually generate separate model names for each bin.

Real Time Noise

Some models do not fully implement real-time noise. Many MOS models include frequency dependent gate noise and this is not included in real-time noise analyses. Also some models include correlated noise which is also not included. In most cases these effects are small anyway and have little effect.

You can set this option in AC small-signal noise:

to disable the same effects in AC small signal noise. A comparison can then be made to estimate the effect these noise sources may have in real-time noise. Although the option name suggests that it only applies to MOS9, this does in fact work with all applicable models.

In the case of PSP 102 models, you can instead invoke the Verilog-A based model which fully supports all noise effects in real-time noise analysis. See next section for details.

PSP 102

The PSP 102 nmos and pmos geometric models (level 902) are also available as level 1023. However the two models are implemented differently. Level 902 is implemented through the SIMKIT interface. The model code itself in this case is created using ADMS from the Verilog-A description. However, it seems that the noise model for this is not created from the Verilog-A code and appears to have been hand coded.

The Level 1023 version is built entirely from the Verilog-A code using the SIMetrix Verilog-A compiler but using a more advanced commercial C-compiler than the open source version supplied with SIMetrix. This version has the benefit over the Simkit version that it fully supports real-time noise including correlated effects and gate noise. It is however a little slower - typically about 5-10% compared to the SIMKIT version.

We have done extensive side by side tests of both models and both give identical results to a high degree of accuracy.

PCM Devices

The following table shows the older PCM (Philips Compact Model) devices still supported by the level numbers used for SIMetrix versions 6.2 and earlier. These are provided only for backward compatibility. Note that the PCM interface does not support multi-core simulation and so will run slower than the SIMKIT devices.

Notes on PCM Models

MOS9/11 and Real Time Noise

The gate thermal noise of the MOS9/11 device is not implemented for real-time noise analysis. In practice the effect of this noise component is usually small and only occurs at high frequencies. To investigate the contribution of this component to overall circuit behaviour, it can be disabled in AC noise analysis by setting the option NoMos9GateNoise.

Documentation

Original NXP documentation on these models can be found in a number of PDF files on the installation CDROM and at our web site. Please visit Further Documentation for details.