AnsweredAssumed Answered

CMOS AMP contains no BJT

Question asked by Usoltsev on Mar 2, 2015
Latest reply on Mar 6, 2015 by JinoL



Good day, ladies and gentlemen,

I have a goal to find out COMS OPAMPS that has no BJTs in its. Unfortunately a lot of datasheets have no simplified schame of opamp in it. For example, AD80xx looks nice but i dont know where it contains bjts. ADA4666 looks great but has q1 and q2 bjt.

I would appreciate if somebody provided me a list of such AD OPAMPs.

Problem definition:

I am working in cryogenic laboratory, we are measuring superconductors and 2D materials in the very low temperatures. Signals we are interested in are at low amplitude and leading wires has high resistance( high resistance is needed to make wires low temperature conductance to get lower T in dewar). The best solution is to place pre-amp close to the sample--so opamp has to work in temperatures as low as 4K(about -275C). There are several articals in wich peoples uses comercial opamps for this purposes. The main feature: it must have no BJTs in it since bjts will have no charge careers in such a low temperatures. For example in that article authors tested HMC548 and HMC460(as i know Hittite is a part of AD now) :

everything is ok with them but current consumption(about 60ma) is a bit too high. So i am researching other variants that would suit our purpose.

Best regards, Usoltsev Alexey.