eldo_user

Figure 21-8. Low Pass Filter
Examples
Example 4—AC Analysis of a Low Pass Filter
Summary of Eldo commands used in this example:
• .MODEL—Model definition.
• .SUBCKT—Subcircuit definition.
• .AC—AC analysis.
• .PLOT—Plot simulator results.
Netlist Explanation
Low Pass Filter incorporating a Voltage Amplifier
.model q2n2222 npn is=1.9e-14 bf=150 vaf=100 ikf=.175
+ ise=5e-11 ne=2.5 br=7.5 var=6.38 ikr=.012 isc=1.9e-13
+ nc=1.2 rc=.4 cje=26p tf=.5e-9 cjc=11p tr=30e-9 xtb=1.5
+ kf=3.2e-16 af=1.0
The above lines describe the electrical parameters of the npn bipolar transistor model q2n2222.
.subckt amp in out vdd
The above line indicates the start of the voltage amplifier subcircuit definition. The subcircuit is
called amp and is connected between the nodes in, out and vdd.
c30 in 31 47u
r30 31 33 390
r31 vdd 33 50k
r32 33 0 15k
q30 out 33 0 q2n2222
r33 vdd out 750
.ends amp
The above line indicates the end of the definition of the subcircuit amp.
Eldo® User's Manual, 15.3 1281