PMOS Common-Source Amplifier

(NMOS)

DC drain current voltage relation (PMOS).

Gain versus I_D.

Gain versus I_D, V_effp.

LabVIEW Computations

Components

Procedure

Install RD value. Adjust VSG in SetVSD.vi and run the VI to find the value for I_DMAX = 500 mA ± 50 mA. VSS is ramped up from 10 V (default value) to find the value for V_D = -4 V. Note that if RD is too large, VD will be > -4 V initially (for V_SS = -10 V) at I_Dmax. Default and save the Front Panel.

LabVIEW Computations

Components

Same as SetVSD.vi

SubVI's

SetVSD.vi (Set Bias)

FG1Chan.vi (Function Generator)

SR.vi (Send-Receive Function)

Oscilloscope.vi (Chan1_in Read Waveform)

Procedure

Sub VI FG1Chan.vi sends out the bias VSG and, in series, a sine-wave signal equal to V_SG/20. Set VSGinit as determined with SetVSD.vi as the VSG required to obtain I_D mA. This is the initial VSG in the sweep of the next part. Run the VI to obtain the gain for this bias current. Obtain a data log of the Front Panel. Default and save. Re-run with a new VSGnew = VSG - 0.5 V to obtain the gain at a lower bias current. Obtain a data log.

LabVIEW Computations

Components

Same as SetVSD.vi

Sub VI's

GainSub.vi

SetVSD.vi (Set Bias)

FGsine.vi (Function Generator)

SR.vi (Send-Receive Function)

Oscilloscope.vi (Chan1_in Read Waveform)

Procedure

Run Gain.vi to run GainSub.vi over a range of currents. Set VSGinit(V) to the value obtained above for I_D mA (defaulted in SetVSD.vi). The VI automatically halts (decreasing) at I_D mA. Default and save the Front Panel. Now obtain a data file as follows.

Open GraphToDataFile.vi (copy of XYtoDataFile.vi) in Project05.llb. Copy the data from the graph ID versus VSG of Gain.vi. (Right Click on the graph, then Data Operations>>Copy Data.) Then paste the data into the Control Graph of GraphToDataFile.vi. (Right Click on the graph and then Data Operations>>Paste Data.) Type the data file path and name the data file. Run the VI to obtain a data file to be read by the Mathcad evaluation file. Repeat for the gain plot, av versus ID. Recall: The data files must be in the folder with the Mathcad file. The file name must have a *.prn extension.