AD8476 Overvoltage Output

In the datasheet there is mention of ESD clamps on the inputs, but are there clamps on the outputs as well? If so what current can they tolerate? This is of importance when the output voltage exceed the rails. We need to analyse the failure mode when connections are made incorrectly.

  • 0
    •  Analog Employees 
    on Nov 18, 2015 5:37 PM

    Hi Michael,

    According to the product owner of the AD8476, the device has ESD protection diodes at the output. The ESD diodes can handle up to 100 mA of continuous current with no observed failures and it can handle the repeated stresses at that level. If you look into the datasheet of the AD8476, the short-circuit current of the device has a typical value of 35 mA. Based on that data, there's no need to implement an external circuit for current-limit protection. The diodes can handle the current even when the output of the AD8476 is saturated.

    Can I ask what is your application?

    Regards,

    Jay

  • 0
    •  Analog Employees 
    on Nov 27, 2015 4:21 PM

    Hi Michael,

    I want to clarify that the short-circuit current limit is a current limit designed into the output stage to make sure that the amplifier is well-protected and not damage when the output of the part is accidentally shorted or connected to ground.

    But if something external is driving a high-voltage into the output of AD8476, that will turn-on the ESD diodes, then it bypasses the output stage so it will bypass the short-circuit current limit completely. If that's the case you still need an external protection.

    Regards,

    Jay

  • We are making the AD8476 robust against 36V being applied across the outputs with no power supplied to the part.