Good and fast way to detect genuine or counterfeit op amps

[AdamFrisen]

Any suggestions?

Defective op-amps are easy but whether it is genuine or counterfeit op-amp is much harder.

 

[living sounds]

Buy only from certified suppliers.

 

[AdamFrisen]

If I buy from certified suppliers, I wouldn't have to detect whether it's genuine or counterfeit, which defeats the purpose of this post.

However I agree it is a valid point you are making.

 

[JohnRoberts]

Back in the 70s/80s for my kit company I would pretest the op amps I sold to kit customers so I could know that they were good before the customer touched them. Modern op amps makers have gotten a lot better but back in those earlier days I would detect single digit weak op amps from testing a several hundred to one thousand piece op amp batch.

The test I used was to run the op amps at extremely high AC coupled gain in the inverting mode, running through all four op amps inside a quad op amp (like tl074) in series. I used a ZIF (zero insertion force socket) to help deal with inserting that many parts. This high gain test would reveal noisy inputs and/or weak open loop gain. IIRC I used something like a 10k sine wave source.

By the late 70s/early 80s the parts quality and reliability had improved to the point that I no longer needed to test them 100%

JR

 

[gyraf]

..most expensive parameters are probably input offset and gain-bandwidth-product, so a fake would miss out on these. Just measure as per data sheet?

/Jakob E.

 

[JohnRoberts]

..most expensive parameters are probably input offset and gain-bandwidth-product, so a fake would miss out on these. Just measure as per data sheet?

/Jakob E.

back in the 70s I screened for input noise and gain bandwidth... Bifets were not bought for their DC performance.

JR