I just picked up a few OPA637's on ebay, but there is text on the bottom of the chips and my 627 don't have anything under the IC. The bottom says TWN leading me to believe that these are possibly fake chips (made in Taiwan?). Can anyone with OPA637's let me know if there is any text on the bottom of their IC's?
The last bunch of OPA627s we bought from TI all originated from Taiwan. We haven't had any 637s for a while, though, so I can't say. But our Taiwanese 627s have PHILS in the glossy dot on the underside of the chip, for what it's worth.