Hi Dice-K
Difet = Diffused JFET input, which is BB legacy technology, emphasizes ultra-low bias current, high impedance, JFET input.
The linked PCN indicated that the FAB process has changed, and the revision B (SBOS165B) OPA627 datasheet reflects the spec. changes due to the FAB change. The Difet term is likely the marketing term at the time, since the term distinguishes it from a typical junction-isolated JFET designs at the time, highlighting its superior input performance. The current datasheet revision is SBOS165C.
https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6166/PCN20240501000.1.pdf
The performance differences per the new FAB is reflected and documented in rev. history section, and captured a part of it below as an example.
If you have other questions, please let us know.
Best,
Raymond
Hi Dice-K,
Has the input stage structure always been JFET, both in the past and now?
The input op amp stage should resemble the previous block diagram.
The simple answer is Yes, but the related FAB process has changed and the op amp's input impedance has been the identical. There may be some performance differences, but it should be documented in the revision history section.
If you have other questions, please let me know.
Best,
Raymond
