eldo_user

Examples
Example 3—AC and Noise Analysis of a Band Pass Filter
yopa1 opamp2 pin: 5 6 4 0 model: ampop
yopa2 opamp2 pin: 9 11 10 0 model: ampop
The above lines instantiate two operational amplifiers yopa1 and yopa2 of macromodel type
opamp2 (linear 2-pole) connected between the nodes 5, 6, 4 and 0 and between the nodes 9, 11,
10 and 0 respectively. The electrical parameters of the macromodel are defined in the model
ampop.
.ac dec 80 100 10k
.plot ac vdb(10)
The above lines indicate that an AC analysis should be performed on the circuit within the
frequency range 100Hz to 10kHz with 80 steps per decade. A dB/frequency plot of the voltage
at node 10, the output stage of the filter, is requested.
.noise v(10) v1 80
.plot noise db(inoise)
.plot noise db(onoise)
The above lines indicate that a noise analysis should be performed of the voltage at node 10
with the voltage source v1 as input noise voltage. The analysis should be averaged over 80
frequency points. A dB/frequency plot is requested on the input and output noise.
Eldo® User's Manual, 15.3 1279