
Example 5.15: A MESFET Amplifier

** Circuit Description **
* dc supplies
Vdd 1 0 DC +10V
* input signal
Vi 3 0 DC -0.3V
* amplifier circuit
B1 2 3 0 n_mesfet 100
B2 1 2 2 n_mesfet 50
* mesfet model statements (by default, level 1)
.model n_mesfet gasfet (beta=0.1m Vto=-1.0V lambda=0.1)
** Analysis Requests **
* calculate DC transfer characteristics
.DC Vi -10V +1V 0.01V
** Output Requests **
.PLOT DC V(2)
.probe
.end

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A Second-Order HP SAB Circuit (nonideal op-amp)

** Circuit Description **

* op-amp subcircuit
.subckt nonideal_opamp 1 2 3
* connections:         | | |
*                 output | |
*                +ve input |
*                  -ve input           
Ricm+ 2 0 500Meg
Ricm- 3 0 500Meg
Rid 2 3 2Meg
Gm 0 4 2 3 0.19m
R1 4 0 1.323G
C1 4 0 30pF
Eoutput 5 0 4 0 1
Ro 5 1 75
.ends nonideal_opamp

** Main Circuit **
* input signal source
Vi 1 0 DC 0V AC 1V
* HP SAB Circuit
X_A1 4 2 4 nonideal_op