[AMPS] strange idling current

[Peter Chadwick]

>which is why one puts c. 100k-ohm resistors in series with the input 
>pins.  

Not if you want the best temperature stability. Because input offset and
bias currents vary with temperature, using 100kohm series resistors
makes it worse:the variation in input offset currents give bigger offset
voltages. A smaller resistor (1k?) should be enough to kill the oscillation
without running into that problem.

But I don't like 723s anyway. An interesting question: How long are they
going to be around? They are an old design, on an old process. The trend is
towards 3 terminal regulators of higher performance; I wouldn't design a 723
into anything on the basis of its age now, and the replacement situation in
few years.

73

Peter G3RZP


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