### At a glance

This tool integrates R. D. Middlebrook's theorems, collectively referred to as the General Network Theorem (GNT) as a new small-signal analysis *gnt* for Spectre/APS in Cadence Virtuoso's ADE L and ADE XL. These theorems allow to decompose a transfer function into lower-level transfer functions by use of signal injections. The interpretation of the lower-level transfer functions depends on the injection configuration. The GNT morphs into:

**General Feedback Theorem**(2GFT): decompose a transfer function in an ideal transfer function, loop gain, null loop gain and direct forward transmission.**Extra Element Theorem**(NEET): find out the impact of one or more elements in the circuit on a transfer function.**Chain Theorem**(2CT): find out loading effects between parts of a circuit, e.g. between amplifier stages.

Furthermore, arbitrary nesting of analyses is possible. You can now, for example,

- analyze
**multiple-loop feedback circuits**: calculate the total Mason's loop gain by nesting 2GFT analyses (this can be regarded as a multiple-loop extension of*stb*) - apply the NEET to find out the effect of multiple elements on circuit performance at once
- find out the effect of interstage loading on loop gain, direct forward transmission from input to output, ... by nesting a 2CT in a 2GFT
- find out the impact of a device on loop gain and stability by nesting a NEET in a 2GFT
- ...

In addition, multiple transfer functions, e.g. input to output, power supply to output, input and output impedances, common-mode and differential mode... can be decomposed in one pass as **MIMO systems** are allowed.

### Deep integration

The *gnt* analysis follows the same use model as other analyses such as *ac*, *stb*,... Results are included in the psf data and accessible in the usual ways (Results Browser and SKILL API). ADE L is fully supported, including parametric sweeps. ADE (G)XL modes such as corners, parameters, monte carlo sampling, sensitivity analysis, optimization, worst-case corners are supported.

### Getting started guide

A walk-through document is included to get you started.

### Example library

A library with examples and references to key publications is included.

### More information

Downloads, documentation and references can be found on www.analogdesign.be.

An overview of an earlier version of the tool was presented at CDNLive EMEA 2014 (accompanying paper).