Line 1: |
Line 1: |
| This page contains a list of all currently known problems with the amplifier board and the solutions implemented | | This page contains a list of all currently known problems with the amplifier board and the solutions implemented |
| + | |
| + | = Issue List = |
| + | |
| + | * check that the summing circuit is up to date |
| + | * finalize DC plane "fingers" |
| + | * settle on switch circuit design |
| + | * check voltage references |
| + | * check impedance matching, where relevant (possible on internal layers?) |
| + | * ensure sufficient bypass |
| + | |
| + | |
| + | |
| + | |
| + | = Bug List = |
| | | |
| == Improper DC levels from voltage regulators == | | == Improper DC levels from voltage regulators == |
Line 23: |
Line 37: |
| | | |
| The adjacent diagram shows the necessary circuit. The component values are set as follows. | | The adjacent diagram shows the necessary circuit. The component values are set as follows. |
− | * Recommended values for V<sub>cc</sub>-V<sub>B4</sub> = 0.9V - {R1,R2}={30kΩ,100kΩ} | + | * Recommended values for V<sub>cc</sub> - V<sub>B4</sub> = 0.9V - {R1,R2} = {30kΩ,100kΩ} |
− | * Good value for I<sub>k</sub> 2mA. Current through R1, R2 is negligible, as is the current going to the load (6 summers x 10uA base current) This I<sub>k</sub> ~ I, so R ~ 2kΩ (but anywhere 1-5kΩ works) | + | * Good value for I<sub>k</sub> is 2mA. Current through R1, R2 is negligible, as is the current going to the load (6 summers x 10uA base current) Thus I<sub>k</sub> ~ I, so R ~ 2kΩ (but anywhere 1-5kΩ works) |
| + | * 154Ω worked well for the emitter resistor (R<sub>f</sub>) on the summer input stage. |
| | | |
| == Wrong voltage on R<sub>C</sub>/R<sub>D</sub> junction == | | == Wrong voltage on R<sub>C</sub>/R<sub>D</sub> junction == |