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Vintage threads from the first ten years

Re: Source for CA3094

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12/3/1999 4:51 PM
R.G.	Re: Source for CA3094 I found a couple of sources for them at about $1.25 each. However, they have definitely gotten harder to find since I last looked. They're still in production by Harris Semiconductor, who bought all of RCA's semi lines.

12/3/1999 6:59 PM
CJ Landry	Harris is now Intersil!! Man, everybody is merging or being bought out. Whatever happened to the small mom/pop operations?

12/3/1999 8:14 PM
Don Symes	mom-and-pop semiconductors? Out of total ignorance, I ask: Can't you stack a PNP/NPN pair on the OTA's output and use its feedback loop to linearize 'em?

12/3/1999 8:38 PM
R.G.	Sure. But when you've done that, what you have is an opamp. The variable gain of the OTA is hidden by the feedback loop.

12/3/1999 9:25 PM
Don Symes	Hmm. Voltage follower ouput buffer, then? For some reason, I'm trying to solve the 3080's lack of current drive, when what you want is some 3094's, so I'll just let it drop.

12/3/1999 10:03 PM

quote:
"I'm trying to solve the 3080's lack of current drive, when what you want is some 3094's"

I reviewed the notes, so I'm not sure exactly what you're after here, but all OTA's have output currents that are equal to the bias current into the control pin times the difference in the voltages at the inputs. If you're after higher currents you have to goose up the bias current. The max current into the bias pin is usually 1ma.

12/3/1999 8:40 PM
R.G.	Not to worry. A CA3094 is a CA3080 with a darlington emitter follower tucked inside. You could still use CA3080's with an MPS A13 follower. The LM13700 is available as well, although I'd have to rip up most of the board to get that in there. Later Small Stones did use the 13600/13700.

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