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TLV9302: Adding TVS Diodes to Op Amp Inputs

Part Number: TLV9302

Hello,

 

I have a quick questions: is it common to add TVS diodes or other overprotection devices for op amp inputs? One of my customers is considering doing so with the TLV9302, but they are concerned they might end up introducing input offset error and reducing precision. They’re concerned about damaging the op amp and the adc inputs into which it’s feeding.

Thanks!

  • Hey Quentin, 

    Thanks for posting on e2e. 

    Do they want the external TVS diodes on the input because they expect the input voltage to exceed the the power supplies? 

    I recommend sharing section 7.3.1 of the datasheet: 

    The TLV930x tolerates a maximum differential swing (voltage between inverting and noninverting pins of the op amp) of up to 40 V, making the device suitable for use as a comparator or in applications with fast-ramping input signals.

    If the customer is still adamant of implementing the TVS diode protection, I recommend that the forward voltage of the diodes be less than the forward voltage of the op amp's ESD protection diodes (0.7V) so that the current will start flowing through the external diodes and not the internal ESD ones. 

    If the current were to flow through the ESD diodes it needs to limited to less than 10mA: 

    The tradeoffs to the diode clamping circuit is reduced precision, exactly as the customer already suspects. 

    All the best,
    Carolina