Instrumentation Amplifier comparison

Discussion in 'General Electronics Chat' started by Dritech, Dec 7, 2015.

  1. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
    756
    5
    Hi all,
    I was comparing three IAs (AD624, AD8421, LT1167) which will be used for EMG signal acquisition.
    From my comparison (voltage and current noise, CMRR, voltage and current offset, bias current, PSR, nonlinearity etc...) I determined that both the AD8421 and the LT1167 are better than the AD624.

    Now I have two questions:
    1) Am I correct in saying that the LT1167 is the best from all three ICs?
    2) If AD8421 and the LT1167 are better than the AD624, why is AD524 the most expensive from RS components?
     
  2. crutschow

    Expert

    Mar 14, 2008
    12,995
    3,229
    If the LT1167 has the best specs for your requirements, then it's the best of all three for you. :rolleyes:
    AD devices are sometimes more expensive than those from other manufacturers with comparable specs.
    More expensive doesn't always mean better.
     
  3. OBW0549

    Well-Known Member

    Mar 2, 2015
    1,308
    884
    I used the LT1167 in a strain gage amplifier and it performed well. I've also used the LT1789 in applications where very low operating current (95 μA max.) and single-supply operation were important.
     
  4. Dritech

    Thread Starter Well-Known Member

    Sep 21, 2011
    756
    5
    You've got a point there because I compared two different brands, but AD8421 is also from AD and it is also cheaper and with better specs.
     
  5. crutschow

    Expert

    Mar 14, 2008
    12,995
    3,229
    Sometimes a manufacturer will come out with a device with improved specs for less money because it's built with a newer semiconductor process that allows the chip to be both better and smaller (and thus cheaper) at the same time.
    But they keep the older legacy devices in production to support those manufacturers who are still using the part in their production PC boards.
    They don't want to alienate the manufacture by forcing them to have to redesign the board because they have stopped producing an older device, even if a better one is available.
     
    Dritech likes this.
Loading...