Micrel MIC860 and MIC861

Oops, typo in the title. These are 3 to 4MHz opamps.

I'm unclear how you came up with that figure of merit. I would expect to divide the GBP by the operating current, so 4 MHz / 33 uA. I don't get anything like 90. Am I doing this wrong?

BTW, the 860 is 4 MHz, but the 861 is only 400 kHz GBP.

Rick C.

Yes, you're right. So the FOM would be 121 MHz/mA, and higher is better. Sorry, the dual p/n is '862.

LTC6246 is 180M at 0.95 uA

Thanks, that's superior! Also LTC6255, 6.5MHz 65uA, matches the MIC860's FOM. And they have enable pins.

So it is unimportant for you if you get high speed or low current as long as as current * GBW is large?

I wonder what application?

That figure of merit is useful, but only within a set of parts that otherwi se meet a given specification. In particular, the GBW product disqualifies slower parts for many applications regardless of power and vice versa, not to mention many other factors such as power supply voltage range.

Rick C.

Certainly, but a table of parts with best FOM numbers would be a good place to consult for a minimum current drain part, once you establish the other criteria.

Wow, making op amp tables sounds like a lot of work. Who'd do a thing like that? ;)

Cheers

Phil Hobbs

I tried creating a table of ARM CPUs and features sometime around 200x. Within a year the size grew to double and after that I couldn't keep up with the rate they introduced new devices.

Rick C.