Parametric Sweep—Family of Transfer Curves

A question we would like to ask is, how does the transfer curve of the circuit from the previous section change as we change the driver MOSFET width-to-length ratio We would like a family of curves that show the effect of changing the driver width. Families of transfer curves can be generated using the Parametric Sweep in conjunction with the DC Sweep or by using the Secondary Sweep. The Secondary Sweep was demonstrated in Section 4.D.2, so we will demonstrate the Parametric Sweep here. 

A Parametric Sweep allows us to sweep a parameter. We would like to sweep the width of the driver MOSFET in the circuit of the previous section. We are assuming that you have followed that procedure and have set up the MOSFET models and DC Sweep. We must first set up a parameter for the width of the driver. We will start with the completed circuit from the previous section. It is repeated here for convenience. 

Double-click the LEFT mouse button on the text W = 1U next to the driver MOSFET  

We wish to enter a parameter for the value instead of III. Type the text W val  

The driver width is now the value W val In PSpice, any text enclosed in curly brackets is referred to as a parameter. A parameter can be assigned different values and can be changed during a simulation. 

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