Electronics > Projects, Designs, and Technical Stuff

Chip doesn't show up in manufacturer's parametric search?

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Kleinstein:

--- Quote from: David Hess on May 05, 2019, 12:51:31 pm ---
--- Quote from: maxwell3e10 on May 05, 2019, 12:18:11 pm ---OPA627 is actually quite expensive, $25 per chip, at least through the major distributor channels. Perhaps the reason in that case is that they have few major customers and want to run the production as infrequently as possible.
--- End quote ---

Burr-Brown always charged a premium but that is excessive.  I suspect the high cost comes from being fabricated on an old process.

Analog Devices' version, the ADA4627, is $8 but not available in the DIP package.  I am not aware of any other direct replacements without knowing more about the application.  There are no comparable CMOS parts.


--- Quote ---But it seems that one shouldn't trust TI website for a complete list of their own chips.
--- End quote ---

I have not trusted TI's selection guides for years because of missing parts.

--- End quote ---

The OPA627 is a DI isolated JFET OP - so it's a kind of special process, in my understanding a little like SOI. The really special feature is the low input bias. The low input bias also needs relatively expensive testing for low leakage. The offset trimming can also make old designs expensive.

If a little more bias can be tolerated the OPA140 or OPA827 might be an alternative.

jaromir:

--- Quote from: maxwell3e10 on May 05, 2019, 01:01:17 pm ---For OPA627 there are a few listed on e-bay. I wonder if they are real or fake:

https://www.ebay.com/itm/5pcs-OPA627AP-OPA627-Precision-High-Speed-Difet-DIP-8/251728025314?hash=item3a9c28d6e2:g:mgMAAOSwiCRUcC6B

https://www.ebay.com/itm/5pcs-OPA627BP-OPA627-precision-high-speed-op-amp-DIP-8/170962971791?hash=item27ce2fec8f:g:AJAAAOxypthRw8di

--- End quote ---

Not sure, but there is known history of "not-that-exactly-real" OPA627's from cheap sources
https://zeptobars.com/en/read/OPA627-AD744-real-vs-fake-china-ebay

maxwell3e10:

--- Quote from: jaromir on May 05, 2019, 01:57:01 pm ---Not sure, but there is known history of "not-that-exactly-real" OPA627's from cheap sources
https://zeptobars.com/en/read/OPA627-AD744-real-vs-fake-china-ebay

--- End quote ---

Interesting. So they are probably fake!

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