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I have been using the INA114 in my design, but wondering if I can use the INA826 instead. I cannot figure out what the difference between these two instrumentation amplifiers is. The CMRR is nearly identical. Is it just the extra gain the INA114 is capable of? There are so many different instrumentation amplifiers out there and I’ve been scouring the datasheets trying to understand what makes one more expensive than the other. The INA has a higher operating current as well. I must be missing something.I am amplifying a wheatstone bridge signal.

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  • \$\begingroup\$ I did not go fully through the datasheets, but I can give you one word of advice: when picking a component, always check the date of the datasheet. The INA114 is much older than the INA826, perhaps it costs more just because the technology is not used anymore, or there is little demand - and therefore little offer. There is no rule on "how old is too old" but I always tend to prefer parts designed in the last 10 years or so, no earlier than that. The technology and materials have changed wildly in the last 30 years. \$\endgroup\$ Dec 9, 2023 at 6:49
  • \$\begingroup\$ The INA114 has higher gain ti.com/lit/ds/symlink/ina114.pdf than INA826 ti.com/lit/ds/symlink/… \$\endgroup\$
    – liaifat85
    Dec 9, 2023 at 16:11
  • \$\begingroup\$ Thanks Vladmir! Older chips make a lot of sense as to why they are more expensive. Older manufacturing processes and lower supply and demand. \$\endgroup\$ Dec 9, 2023 at 21:53

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Additional to the important point about the age of ancient chips Vladimir Cravero mentioned in his comment, there is also a drawback of the newer chip:

Input bias current: The INA114 has input bias current cancelation and can achieve +-2nA of input bias current. The INA826 goes up to 65nA or even 95nA over full temperature range. Depening on the source impedance of your signal source that might make a difference or it might make none.

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  • \$\begingroup\$ That’s the elephant in the room along with the age of the chip. Thanks jusaca! \$\endgroup\$ Dec 9, 2023 at 21:58

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