At 08:12 AM 02/04/2012, you wrote:
> > LT1678 might work for you, assuming you're using it as an op-amp and
> > not as a comparator.
>
>Yes, as a differential op-amp actually. The only scarry thing about
>your suggestion is the price.
>Is there a cheaper alternative or almost all rail-to-rail op-amps are
>this expensive ?

Depends if you need rail-to-rail input AND output, what bandwidth,
etc.

For example, OPA2171 is only $1.85 in small quantities, is R-R out,
and the input CM range includes the lower rail, but only within 2V of the
upper rail.

High voltage RRIO op-amps tend to be expensive, and because you essentially
need more than one input stage to deal with different CM voltages, they
often do some funny things as you change the CM voltage (like the offset
voltage shifting around a bit at the transitions).

BTW, the LTC part might be cheaper if you get it direct from Linear.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the rewar=
d"
speff@interlog.com             Info for manufacturers: http://www.trexon.co=
m
Embedded software/hardware/analog  Info for designers:  http://www.speff.co=
m



--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.