LM 2901 & LM 339

[StephenGiles]

I'm playing around with some Spacedrum type circuits (all in the general scheme of things), one of which requires LM 2901 which I don't have, but see from the data sheet that it's grouped with the LM 339 bunch. Presumably they are almost interchangeable??

[anotherjim]

I would say so. In the past I've studied the data and lost the will to carry on while trying to find differences with 2901 that mattered.

[StephenGiles]

Thanks

[PRR]

I think they are the same die, sorted to different specs and prices.

LM3302 appears to be the lowest spec. Notably it is rated only 28V supply, the others for 36V. Not an issue for 9V or 18V work.

LM339 has the best specs. 2mV input offset, others are 5mV or more. I really doubt this will matter for any stomp or small-audio application.

In truck-loads I am sure they are different prices. That '3302 is low-price for jobs that don't need the very best; and you pay more for LM139A with the lowest offset. That they bake the silicon, then test-out for LM139A parts, then for 2901 parts, and any parts that don't bake-up to full 36V breakdown get sold as 3302.

In ones and tens, the price may be all the same, more in handling (breaking-down cartons of 500 to individual orders) than actual part-cost.

[anotherjim]

The odd number could signify it was originally a custom design for a customer who had exclusivity for a contractual period. National then made their own version for general use. Period expired, the custom part joined the flock with the original spec's separately defined.

Or it could signify a "second source" from a different plant. Back then, the big boys like IBM wouldn't use anything unless it was made in more than one, geographically separate, locations.