IC Op-Amp questions.

[kevink]

Love the kits. Have built 5 so far. 3 to go

I have noticed on the A12 info page that an AD797, or OPA627 IC op-amp can be used. The A12 assembly instructions state that some IC op-amp types may need to have some parts around them changed. Do the above stated op-amps require such changes?

Also, in the A12 assemble instructions, it is recommended to consult the data sheet of the IC op-amp of choice. What specifications should I be looking at in the data sheet?

Does anyone have any successfully used IC op-amps to suggest?

[niccolo]

honestly, I see no reason why you would want to use an IC instead of the very good discrete opamps SCA could provide you..

Apart from this I'm sorry I have no other suggestions..

sorry


nicco

[Mylithra]

If you plan on using a 8 pin DIP opamp, The biasing may be a little different. Also the bypassing caps (I think its C4 and C5 on these) may need to be a different value if you dont use a DOA (like the SC25). Check the schematic. Tim put a reference for the AD797 and the LT1013 in there. While I understand the cost difference, a few dollars as opposed to 50-90 it would cost for a DOA, but I'll tell you.. I think its worth it.

[kevink]

Thanks for the advice so far. I definitely will not argue against DOAs superiority. I was thinking about an IC as more of an experiment.

When I originally took a look at the A12 schematic I dismissed the bits about the LT1013CN8 and the AD797 because I thought they were for the DC servo option. After looking at it closer I now see that the bit about the LT1013CN8 is for the servo option but the bit about the AD797 is what I was looking for. However I still have a few questions.

1. It appears from the bit on the power supply schematic regarding the AD797 that C4 and C5 should be left out. Is this correct?

2. On the I/O schematic I see the values for C7 and R22 when using an AD797 but are those in addition to or in place of C6 and R23?

[tpryan]

When I originally took a look at the A12 schematic I dismissed the bits about the LT1013CN8 and the AD797 because I thought they were for the DC servo option. After looking at it closer I now see that the bit about the LT1013CN8 is for the servo option but the bit about the AD797 is what I was looking for. However I still have a few questions.

Page 17 of the assembly instructions provides some details on the optional features of the board.

1. It appears from the bit on the power supply schematic regarding the AD797 that C4 and C5 should be left out. Is this correct?

No, C4 and C5 should be installed for either type of op-amp.

2. On the I/O schematic I see the values for C7 and R22 when using an AD797 but are those in addition to or in place of C6 and R23?

C7 and R22 will in some cases replace C6. R23 remains installed in all cases.