Band-gap Reference Simulation - Problem Set #5, Problem 2

* Specify the parameters in one place, for easier changes.
*
*3 cases:
*	1.  isat1 and isat2 normal;  r3 adjusted for TC=0 at 25 deg C
*	2.  isat1 and isat2 doubled; r3 same as in case 1
*	3.  isat1 and isat2 doubled; r3 adjusted to make Vout = target (case 1)
*Case 1:
.param isat1=1.25e-17 isat2=1e-16 r3=2.34k

* Test circuit
q1     0  0    1 mod1
q2     0  0    2 mod2
r1     4  1   1k
r2     4  3   8k
r3     3  2   r3
e1     4   0   1    3 10k

*.nodeset v(1)=0.7 v(2)=0.6 v(3)=0.7 v(4)=1.2

* Don't print the model parameters
.options nomod

* Show the DC operating point
.op 

* Analysis
.temp 0 25 50

.model mod1 pnp is=isat1
.model mod2 pnp is=isat2

*Case 2:
.alter
.param isat1=2.5e-17 isat2=2e-16 r3=2.34k

*Case 3:
.alter
.param isat1=2.5e-17 isat2=2e-16 r3=2.24k

.end