Instrumentation Amplifier comparison

Thread Starter

Dritech

Joined Sep 21, 2011
869
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?
 

crutschow

Joined Mar 14, 2008
25,121
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.
 

OBW0549

Joined Mar 2, 2015
3,449
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.
 

Thread Starter

Dritech

Joined Sep 21, 2011
869
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.
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.
 

crutschow

Joined Mar 14, 2008
25,121
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.
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.
 
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