MAX9632???

[cyaniccypher]

Does anybody here have experience with the MAX9632?

MAX9632 36V, Precision, Low-Noise, Wide-Band Amplifier - Maxim

At least on paper it has some amazing specification. I am wondering how it would compare against OPA1611, AD8599, AD8610, OPA827...


View attachment MAX9632.pdf

Thanks;
Leo

 

[cliffforrest]

Yes, I've used the MAX9632 in a number of roles, buffer amplifer e.g.

It performs very well, but beware of the high(ish) input bias current.

 

[sgrossklass]

But Ib is only supposed to be 30 nA (typ), that's not high(ish) for a bipolar, now is it?

Current noise density, by contrast, is on the high side indeed, even for a very low voltage noise part - 3.75 pA/sqrt(Hz) (some of it likely to be correlated due to input bias cancellation circuitry). Ironically, that means it has somewhat higher noise in the "Typical Application Circuit" shown in the datasheet when compared to medium-low noise parts like NE5534 or OPA227, simply because surrounding impedances aren't low enough! LME49990, ADA4898-1, AD797, LT1115 all have lower Inoise. Degenerated input stage maybe?

Opamp manufacturers don't like to tell you that their parts cannot generally achieve both their amazing noise specs and distortion specs at the same time, not at low gains anyway (because low noise = low feedback network values = high output loading at line level). Modern parts should be better at this though. Some '80s ones are real stinkers, basically you almost have to class A bias and strap a driver stage on 'em.