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previous: HM Re: Q&D Compressor-just hooked it up -- 3/14/1998 2:20 PM View Thread

Re: LM308 substitute

3/15/1998 2:30 AM
Jack OrmanRe: LM308 substitute
Any one know a replacement for a LM 308 N same pinout. 071 081 ?  
the 71 and 81 are the same pinout; however, the 308 is an uncompensated op-amp. In many early design op-amps like the 308, an external cap is used to restrict the freq limits to control oscillation and other characteristics. Later on the techies found a way to put a small cap on board the op-amp and eliminated the need for external compensation. Typically a small value cap is connected between pins 1 and 8 of the LM308 for compensation. If this is the compensation method (ie. the only connections to pins 1 and 8) then a TL071 or TL081 can probably be dropped in its place since they have no connection at pin 8. An alternate compensation method for the LM308 is for the cap to be connected from pin 8 to ground and the TL substitutes will probably work here as well.  
regards, Jack

HM Thanks Jack! -- 3/15/1998 4:02 PM