GA-Spice Example: Operational Transconductance Amplifier
Problem Description
- Achieve desired transconductance while properly biasing all transistors.
- Transistor widths fixed at 2 micrometers. Transistor lengths encoded as problem variables. R1 also encoded as a problem variable.
- Chromosome length = 76 bits for 7.5x1022 possible solutions
- Solve time approximately 15 minutes on 200 MHz Pentium II notebook computer.
Design Objectives and Program Results
| Objective | Result |
| 1.4 V < V(12) < 1.6 V | V(12) = 1.44 V |
| 1.1 V < V(9) < 1.3 V | V(9) = 1.18 V |
| 3.7 V < V(6) < 3.9 V | V(6) = 3.88 V |
| 3.0 V < V(10) < 3.2 V | V(10) = 3.13 V |
| 3.0 V < V(11) < 3.2 V | V(11) = 3.13 V |
| 3.7 V < V(13) < 3.9 V | V(13) = 3.90 V |
| 0.8 V < V(1) < 1.0 V | V(1) = 0.99 V |
| 95 uA/V < gm < 105 uA/V | gm = 100.5 micro Amperes / Volt |
If you would like more details on this problem or further information on the GA-Spice program please send an e-mail to Dr. Ross.