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AMC3336: Condition of the device when there is no power

Danilo A.
Mastermind 25695 points
Part Number: AMC3336

Hi Team,

We would like to ask your help regarding our customer's inquiry below.

I'm designing an AC voltage measurement circuit. I have a question about your AMC3336 IC.

If the supply voltage(VDD) does not come to the IC, what value is seen on the HLDO_OUT pin?

How does the device work if the HLDO_OUT value is zero?

How are the INP and INN pins affected in this case?

I am working with 440V AC voltage. I get 1VAC by reducing this voltage value with resistors on INP and INN pin.

If there is no supply voltage on AMC3336 and no voltage is supplied to the HLDO_OUT pin, how is the value seen on the INP and INN pins, will the device be damaged or burned?

Regards,

Danilo

  • 0
    TI__Mastermind 22950 points

    Hi Danilo,

    VDD is connected to an internal LDO which is then connected to a transformer driver circuit. This then excites the secondary coil and generates the high side supply. So in short, if VDD is not connected, HLDO_OUT will be at 0V and if there is no HLDO_OUT, then the device will not be operational. 

    Regarding the input pins... If +/- 1V is applied at the inputs before VDD is present, then that would violate the ABS MAX ratings of the device. The device specs that the absolute maximum voltage applied across INP and INN should not exceed HLDO_OUT + 0.5V. If the ABS MAX ratings are violated, then the device can exhibit unexpected behavior and over long term, even become damaged. Our recommendation here is to ensure that the ABS MAX ratings are not being violated. 

    Regards,

    Aaron Estrada