I have a square wave circuit based on a 555, (2) CD4017, a CD4013 which in turn feeds the square wave to the UAF42. Is it a requirement that the V+ and V- for the UAF42 be separate from the other IC's (555, CD4017 & CD4013) supply voltage? Will the UAF42 only function if connected in this way? The only way I have been able to produce a sine wave from the UAF42 is if the supply voltages are separate from the other IC's in the ckt.
It should not be necessary to use separate power supplies. I believe that you are probably not connecting the supplies correctly. Can you please provide a schematic showing your full circuit? Be sure to clearly indicate how the supply connections are interconnected.
I have verified all of my connections are correct according to the datasheet. I have attached the schematic of my circuit. I'm using a bench-top power supply for the +/-12VDC and the gnd.
I don't see any reason why using the same power supply should cause a problem. A power supply providing +12V, ground and -12V with the +12V and ground shared with the UAF42 should work well. I believe that you are probably overlooking some simple interconnection problem.
To troubleshoot, I suggest the following: Measure with the ground of an o-scope connected to pin 11 of the UAF42. Pin 10 should be +12V. Pin 9 should be -12V. Pin 2 should have a square wave from 0V to 12V.
Not quite sure what's going on with this circuit. I agree that the UAF42 should work well with the other circuits as I have them connected. I have verified all the connections and have also verified the +/-12VDC, gnd and the square wave coming into pin 2 using an o'scope. I have noticed that pin 7 is -12VDC. (I have also tried another UAF42 to rule out a bad chip). But if I connect the UAF42 to a separate supply, I get the sine wave output on pin 7, however the output rides on a negative output voltage. I am using a breadboard and thought that may have been an issue due to a connection problem so I relocated the UAF42 to a different section with the same results. I may just have to actually solder all of the components to insure proper connections.
On a similar note, I constructed a similar circuit but utilized a CD74HCT390 versus CD4017. I used the same +/-12VDC and gnd. This circuit worked with all IC's connected to the same supply voltages. The only reason I wanted to use the CD4017 is the higher supply voltage and higher output voltage range.
Hummm? I can't explain it. I still believe it's a hookup issue of some type. It's happened to us all. :)
Further diagnostics: Connect o-scope ground to pin 11 of the UAF42. Measure the voltage on the ground of the 4013 (should be zero). Supply pin of 4013 should be +12.
It turned out to be a problem with an entire section of my breadboard. Not sure exactly what happened with that particular section. Voltages, signals, etc. looked fine but when I placed the UAF42 on an entirely new section, it worked fine. Thanks for your help.
Good. I'm glad you found it. As I said, it's happened to us all.
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