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INA129 Input Over-voltage protection

Jeff McDevitt
Expert 1775 points
Other Parts Discussed in Thread: INA129, INA128

Hello,

How well will the INA129 handle (or perhaps ignore) a very large voltage spike lasting for several hundred microseconds?

Does the protection of up to +-40V mean for a continuous input of +-40V?

Thanks,

Jeff

  • 0
    TI__Mastermind 25775 points
    Hello Jeff,

    The INA128/9's inputs are protected up to +/-40V by limiting the input current. However, it is difficult for me to say the conditions under which this was tested because the device is ~20 years old...I am unable to locate any data relating this specification to duration/frequency.

    Therefore, if you're expecting large, fast transients on the inputs I recommend implementing a more robust solution than relying on the device's internal protection. This would include external common-mode and differential mode filters and TVS diodes to attenuate/clamp the voltage. Also, you may want to consider ferrite beads in series with the inputs in order to limit the current. If the input ESD structures start to conduct due to the fast transient, excessive current (e.g. ~10mA) will damage the device.