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112 2. Tutorial
In[11]:= diffAmp =
Circuit[
Netlist[
{RS1, {1, 2}, Symbolic −> RS1, Value −> 1.*10^3},
{RS2, {3, 0}, Symbolic −> RS2, Value −> 1.*10^3},
{RC1, {4, 8}, Symbolic −> RC1, Value −> 1.*10^4},
{RC2, {5, 8}, Symbolic −> RC2, Value −> 1.*10^4},
{RBIAS, {7, 8}, Symbolic −> RBIAS, Value −> 2.*10^4},
{CLOAD, {4, 5},
Symbolic −> CLOAD, Value −> 5.*10^−12},
{Q1, {4 −> C, 2 −> B, 6 −> E}, Model −> BJT,
Selector −> GummelPoon, Parameters −> BJTNPN},
{Q2, {5 −> C, 3 −> B, 6 −> E}, Model −> BJT,
Selector −> GummelPoon, Parameters −> BJTNPN},
{Q3, {6 −> C, 7 −> B, 9 −> E}, Model −> BJT,
Selector −> GummelPoon, Parameters −> BJTNPN},
{Q4, {7 −> C, 7 −> B, 9 −> E}, Model −> BJT,
Selector −> GummelPoon, Parameters −> BJTNPN},
{VCC, {8, 0}, Type −> VoltageSource,
Symbolic −> VCC, Value −> 12.},
{VEE, {9, 0}, Symbolic −> VEE, Value −> −12.},
{V1, {1, 0}, V1}
],
ModelParameters[Name −> BJTNPN, Type −> "NPN",
BF −> 255.9, BR −> 6.092, IS −> 14.34*10^−15],
GlobalParameters[TEMP −> 300.15]
]
Out[11]= Circuit
Setting up the circuit equations in the time-domain yields the following DAE system of 32 equations
in 32 variables.
In[12]:= diffAmpMNA = CircuitEquations[diffAmp,
AnalysisMode −> Transient]
Out[12]= DAETransient, 32 32
Next, we define the input signal V t. We choose a rectangular voltage pulse with an amplitude
of V, a duration of Μs and a delay of Μs. This waveform can be set by the Analog Insydes
command PulseWave (Section 4.1.3).
In[13]:= Vpulse[t_] :=
PulseWave[t, 0, 2, 2.5*10^−6, 0, 0, 4.*10^−6, 10^−5]
A graphical representation of the stimulus signal is shown below.