PSoC 4 SAR ADC overvoltage problem.

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AlBa_1988666
Level 1
Level 1

If you set Vref 1.024 volts and apply more than this voltage to the ADC input, the chip immediately fails.

In my project, the measured voltage is 0.2 - 0.8 volts, but sometimes it can briefly exceed the level of 1.024 volts, after which the chip immediately fails.

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AlBa,

obviously you have occasional spikes on the pins exceeding damage threshold. Though there are protection diodes, this may be not enough if the spike is long or voltage is too high. You need to add a TVS diodes for protection of the input, something like

SM16LC05E3/TR13 Microsemi Corporation | Circuit Protection | DigiKey

Look for low-voltage breakdown series <5V

/odissey1

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VenkataD_41
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750 replies posted 500 replies posted 250 solutions authored

Hi,

>>"but sometimes it can briefly exceed the level of 1.024 volts, after which the chip immediately fails."

--> Do you mean that the chip damages? Is the chip not working after this incdent?

What is the voltage given on the pins VDDD and VDDA?

Thanks

Ganesh

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Yes,the chip not working after this incdent. After such an incident, a short circuit occurs on the port on which the voltage to ground has been exceeded.

About 20 chips have already gone bad for me.  I use CY8C4245axi-483

I give  on the pins VDDD and VDDA - 5.0 v

0 Likes

AlBa,

obviously you have occasional spikes on the pins exceeding damage threshold. Though there are protection diodes, this may be not enough if the spike is long or voltage is too high. You need to add a TVS diodes for protection of the input, something like

SM16LC05E3/TR13 Microsemi Corporation | Circuit Protection | DigiKey

Look for low-voltage breakdown series <5V

/odissey1