From: Winfield Hill
Subject: Re: accurate fast opamps
Date: 13 Nov 2002 03:34:15 -0800
Organization: Rowland Institute
X-Newsreader: Direct Read News 4.10
> Winfield Hill wrote:
>> Let's talk about our favorite fast accurate opamp, in this case
>> I'm calling out f_T faster than 5 MHz, Vos under 150uV typical
>> (bipolar, right?), Ibias < 20nA. Oh, and operating from 12.5V
>> total supply. :-) Is your favorite choice up to the task?
> I've used the TI TLE2021, which satifies most of your
> list except that it is 2-2.8MHz.
Not at all bad for a 300uA opamp though. Looks good.
> However, just a few pages further on in the TI book
> is the TLE2027.... 25uV, 15(90) nA, 15MHz, 4-0-4 to
> 44-0-44 supply volts.
Another nice one, but with a price to pay for the extra
speed: increased bias current. Although they say 15nA
typical they give themselves a 90nA budget. Working
backwards from the current-noise figure, it looks like
the uncancelled input-pair base current is about 2uA.
Still, I wish I had some of those in my inventory now.
> Further on there are more tasties, the TLE2082 grabs
> my fancy.... it's an 082 with *attitude*.
Yeah, and the "trimmed offset-voltage" claim catches
one's eye. Upon examination we see an enticing 0.3mV
offset, but then we see 3 or 6mV max for the '2081,
and even worse for the '2082. Bummer! But then it
is an economy opamp, not as much as an '082, but in
the under a buck category.
> Macromodels on many data sheets.
A nice touch, column select tool in Acrobat, off we go.
Thanks Tony, those are indeed some nice picks.