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ADS54J66: What is input's real absolute maximum votlage?

Jake Hillard1
Prodigy 20 points
Part Number: ADS54J66


Hi gang,

On pg5 of the datasheet, the AbsMax voltage applied to input pins INAP, INAM is listed as -0.3 to 3V. As those inputs are differential, do I need to level shift my negative up such that my 1vpp signal doesn't destroy the device, or is this a differential line input?

Put another way, which of these will kill the device? 

1Vpp single ended signal -> 0.5Vpp differential signal biased at zero input to INAP, INAM. Both inputs independently receiving max voltages of +-0.25V.

3.5Vpp single ended signal -> 1.75Vpp differential signal biased at zero input to INAP, INAM. Both inputs independently receiving max voltages of +-0.875V. 

6Vpp single ended signal -> 3Vpp differential signal biased at zero input to INAP, INAM. Both inputs independently receiving max voltages of +-1.5V. 

7Vpp single ended signal -> 3.5Vpp differential signal biased at zero input to INAP, INAM. Both inputs independently receiving max voltages of +-1.75V. 

  • 0
    TI__Guru* 91947 points

    Jake,

    Each analog input pin should see an input that is between 1.525V and 2.475V. This is the maximum recommended swing allowed. This is +/-0.475V around the common mode voltage of 2.0V. If you exceed this, the part will clip. If you exceed 3V in the positive direction, you could damage the part. Same if you exceed -.03V.

    It doesn't matter what your differential voltage is, it is the voltage on the individual pin that matters when considering if you might be damaging the part. Are you AC coupling the inputs? If so, your input voltage will swing around 2.0V at the input pins.

    The analog input pins have ESD protection diodes between ground and the pin; and the pin and AVDD3V. The diode turns ON when the input voltage exceeds the AVDD3V by ~500mV, and can withstand 10mA current for 10ms.

    Regards,

    Jim