1. Composite Amplifier Stability Analysis First Scheme & Second Scheme Tim Green, MGTS Precision Linear Analog Applications August 7, 2014 1

2. 2 First Scheme - Loop Gain Op Amp U1 Run DC Operating Point first to be sure all op amp inputs and outputs are in the linear region of operation. Otherwise AC Analysis is not valid if op amp outputs are saturated or common mode inputs violated.

3. 3 First Scheme - Loop Gain Op Amp U1 Loop Gain Phase Margin = 68.9deg

4. 4 First Scheme - Loop Gain Op Amp U2 Run DC Operating Point first to be sure all op amp inputs and outputs are in the linear region of operation. Otherwise AC Analysis is not valid if op amp outputs are saturated or common mode inputs violated.

5. 5 First Scheme - Loop Gain Op Amp U2 Loop Gain Phase Margin = 77.1deg

6. 6 First Scheme - Loop Gain Op Amp U2 Loop Gain Phase Margin = 77.1deg

7. 7 Second Scheme - Loop Gain Op Amp U1 Run DC Operating Point first to be sure all op amp inputs and outputs are in the linear region of operation. Otherwise AC Analysis is not valid if op amp outputs are saturated or common mode inputs violated.

8. 8 Second Scheme - Loop Gain Op Amp U1 Loop Gain Phase Margin = 69.9deg

9. 9 Second Scheme - Loop Gain Op Amp U2 Run DC Operating Point first to be sure all op amp inputs and outputs are in the linear region of operation. Otherwise AC Analysis is not valid if op amp outputs are saturated or common mode inputs violated.

10. 10 Second Scheme - Loop Gain Op Amp U2 Loop Gain Phase Margin = 62.5deg

11. 11 All Embedded Schematics in this presentation can be run in the Free TINA_TI SPICE simulator available at: http://www.ti.com/tool/tina-ti