What are the Operation Region of Transistors in Cadence

How to know the region of operation of a single transistor in Cadence? What are the meaning of 0, 1, 2, 3 and 4 Regions in terms of cutt-off, saturation, sub-threshold, etc

The Virtuoso tool tells us valuable information about the operation region of any transistor in the circuit. For example, if a transistor is working in the saturation or in the triode region.

There is a standard operating point parameter named “region”. Although it depends on each specific technology, most of them are using it.

The condition for saturation region in based on the zeroth approximation:

|Vds|>=|Vgs-Vth|=|Vds,sat|

How to See the Operation Region in Cadence Virtuoso

The easiest way is after a dc simulation you can annotate the operation region in the schematic.

First we annotate the DC operating points

right click on the results of the DC sim >> Annotate >> DC Operating Points

We will see the basic parameters of each transistor, by default Cadence shows the Vss, Id, Vgs and Vds.

To show the “region” parameter on the annotation, we must go to with right click to Annotations >> Setup.

Also you can go to the upper menu

View>> annotations>> Setup

add the component parameter “region”

Also you can make the changes on the menu:

View> DC annotation >Setup > select DC operating region > Display > region