On 9/14/2014 11:55 PM, Bill Bowden wrote:
"Phil Hobbs" wrote in message
...
On 9/13/2014 1:21 PM, John Larkin wrote:
On Fri, 12 Sep 2014 22:52:21 -0400, wrote:

On Fri, 12 Sep 2014 10:58:49 -0700, Jim Thompson
wrote:

I need a rail-to-rail I/O OpAmp, 5V Vcc is fine, slow speed setting a
current mirror.

What specs?

What would you guys in the discrete world recommend as being
well-behaved, no peculiarities, etc? (And readily available ;-)

I've been using the MicroChip MCP6294, mainly because they're cheap
but the specs matter.

That looks OK for non-critical stuff. The single MCP6291 in SOT23 is
around 40 cents in quantity. (I like singles, usually.) Somewhere
there ought to be a really cheap workhorse opamp, ten cents maybe.



Already exists. LM358, $0.09 in quantity 1 from Newark. And it's a dual!


http://octopart-clicks.com/click/vpt...077166e&vpid=1
16013415

Cheers
Phil Hobbs


But the LM358 doesn't use any bias, and so there is crossover distortion at
the mid point if used in a linear application such as audio. Maybe that's
not an issue for other applications?

-Bill

For nine cents in onesies, he expects perfection. An arrant varlet,
forsooth.

LM358s and 324s are occasionally useful, but usually in unipolar
applications, true. A figure of merit for a given design is how crappy
an amplifier you can use and have it still work well.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net