Forums

Op-amp instrumentation amplifier is initial input stage of EKG and EEG instruments

Started by Patrick Chung October 2, 2014
Op-amp instrumentation amplifier is initial input stage of EKG and EEG instruments due to it's high impedance, very high common-mode rejection ratio, and very high voltage gain. Read more:
http://www.cirvirlab.com/index.php/tutorials/162-op-amp-instrumentation-amplifier.html
and simulate online:
http://www.cirvirlab.com/simulation/op-amp-instrumentation-amplifier-online.php
It happens that Patrick Chung formulated :
> Op-amp instrumentation amplifier is initial input stage of EKG and EEG > instruments due to it's high impedance, very high common-mode rejection > ratio, and very high voltage gain. Read more: > http://www.cirvirlab.com/index.php/tutorials/162-op-amp-instrumentation-amplifier.html > and simulate online: > http://www.cirvirlab.com/simulation/op-amp-instrumentation-amplifier-online.php
Idealized! Does anyone make an IA IC as good as a AMP05? I used many AMP05 but that is long gone. AMP05 was excellent and relatively high freq response. Do not buy any surplus AMP05 as they are floor sweepings or mismarked. AD calls it Obsolete but they just do not want to make it any more. Laser trimming got too expensive I guess. But I would have paid for it.
On Thu, 02 Oct 2014 13:40:10 -0700, OldGuy <spamnot@nospam.com> wrote:

>It happens that Patrick Chung formulated : >> Op-amp instrumentation amplifier is initial input stage of EKG and EEG >> instruments due to it's high impedance, very high common-mode rejection >> ratio, and very high voltage gain. Read more: >> http://www.cirvirlab.com/index.php/tutorials/162-op-amp-instrumentation-amplifier.html >> and simulate online: >> http://www.cirvirlab.com/simulation/op-amp-instrumentation-amplifier-online.php > >Idealized! > >Does anyone make an IA IC as good as a AMP05? >I used many AMP05 but that is long gone. >AMP05 was excellent and relatively high freq response. > >Do not buy any surplus AMP05 as they are floor sweepings or mismarked. > >AD calls it Obsolete but they just do not want to make it any more. >Laser trimming got too expensive I guess. But I would have paid for >it. >
For sure it wasn't the cost of laser trimming. Many ADI parts in current production are laser-trimmed. I know, I've designed some of them. The much more likely reason for discontinuance was the cost of fab transfer. The AMP05 was made on an old and unique-to-the-fab process in the San Jose fab, which was closed some years ago. High-runner processes were moved to other fabs, which allowed a number of products to be moved very easily (once the process was moved, a not inconsiderable task). In other cases products were redesigned to use similar existing processes in one of the other fabs (also not cheap). Discontinued products were those that didn't have sales to justify the costs of keeping them alive by either process or design migration.
On Thursday, October 2, 2014 4:40:10 PM UTC-4, OldGuy wrote:
> It happens that Patrick Chung formulated : > > > Op-amp instrumentation amplifier is initial input stage of EKG and EEG > > > instruments due to it's high impedance, very high common-mode rejection > > > ratio, and very high voltage gain. Read more: > > > http://www.cirvirlab.com/index.php/tutorials/162-op-amp-instrumentation-amplifier.html > > > and simulate online: > > > http://www.cirvirlab.com/simulation/op-amp-instrumentation-amplifier-online.php > > > > Idealized! > > > > Does anyone make an IA IC as good as a AMP05? > > I used many AMP05 but that is long gone. > > AMP05 was excellent and relatively high freq response. > > > > Do not buy any surplus AMP05 as they are floor sweepings or mismarked. > > > > AD calls it Obsolete but they just do not want to make it any more. > > Laser trimming got too expensive I guess. But I would have paid for > > it.
TI still makes the Burr Brown INA116U. http://www.ti.com/sitesearch/docs/universalsearch.tsp?searchTerm=INA116u#linkId=1&src=top