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INA117: Finding replacement amplifiers for circuit

Jason Chan42
Intellectual 360 points
Part Number: INA117
Other Parts Discussed in Thread: INA828, INA188,

I'm attempting to repair a circuit for a large instrument. Based on how the circuit is situated, I am attempting to replace some of the op-amps in the circuit. My circuit contains the INA117BM High Common-Mode Voltage Difference Amplifier (TO-99-8 pin) and the INA114BP Precision Instrumentation Amplifier (DIP-8 pin). The issue I'm facing is that the amplifiers are old, and I can't find some of them on Digi-Key. The INA117BM is non-stocked, and it usually runs around $70. On the other hand, the INA114BP is available at the cost of around $13. Regardless of availability, I was wondering what suitable replacements would you recommend for the amplifiers, specifically the INA117BM?

Sorry, I forgot to mention this, but because I am repairing a new piece of equipment and not designing from scratch, I would prefer it if I can match the same layout style as the original amplifier. That would mean for replacing the INA117BM, I would prefer a TO-99-8 pin package or a DIP 8-pin package. It should be noted that the original INA117BM had its legs spread out such that it fit a DIP-8 pin socket, so I'm not necessarily looking to fit a TO-99 socket, but a DIP-8 socket.

  • 0
    TI__Guru* 93105 points

    Hi Jason,

    My thought is to replace the INA117BM, in the TO-99 package with the INA149AID which available in the 8-pin SOIC package. The INA149AID is a newer device with higher performance than the INA117BM.

    Certainly there is the package difference, but there is a solution to that issue; a SOIC-8 to TO-99 adapter. The adapter is not inexpensive, but it with the cost of a new INA149AID is far less than $70. The adapter is made by Aires and is available from DigiKey for $12.24 (Qty 1):

     The INA149AID is available from DigiKey as well for $6.49 (Qty 1):

    Regarding the INA114BP have a look at the following possible replacements:

    INA828

    INA188

    Both of these instrumentation amplifiers utilize the same 8-pin SOIC pin-out arrangement and gain equation as the INA114BP. Be sure to review their datasheets making sure they meet the dc and ac requirements of your application.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • 0 in reply to Thomas Kuehl
    Intellectual 360 points

    Dear Thomas,

    Thank you for your reply. I appreciate the various suggestions that you have given me for the amplifiers, though I'll have to make sure that I have enough clearance for the part with the adapter. My equipment that I'm repairing is packed in tight, so I'll have to check the clearance. I apologize, but I forgot to mention that the original INA117BM had its legs spread out such that it fit a DIP-8 pin socket, so I'm not necessarily looking to fit a TO-99 socket, but a DIP-8 socket.

  • 0 in reply to Thomas Kuehl
    Intellectual 360 points
    Thomas, sorry for replying like this, but in light of this, using a DIP-8 instead of a modified TO-99, would the INA117P be good to replace the INA117BM? I looked at the datasheet and specs from Digi-Key, and they seem to have the same specifications. The only difference is their respective packages.

    www.ti.com/.../ina117.pdf
  • 0 in reply to Jason Chan42
    TI__Guru* 93105 points
    Hi Jason,

    According to the INA117 Specification table the ✻ symbol in the columns indicate "✻Specification same as for INA117AM." The electrical performance of the INA117P will be on par with the INA117AM, which has a little higher maximum gain error of 0.05 % vs the INA117BM's 0.02 %. The "typical" gain error is specified as the same for all versions.

    Regards, Thomas
    Precision Amplifiers Applications Engineering
  • 0 in reply to Jason Chan42
    TI__Guru* 93105 points
    Hi Jason,

    If this has been satisfactorily answered, please click the green "This Resolved My Issue" button so we can close this inquiry.

    Regards, Thomas
    Precision Amplifiers Applications Engineering