More info needed regarding Schmitt Trigger input setting in Max-V CPLD

[griffin1701]

I am looking for the center voltage value for a pin on the Max V CPLD, when it is configured as a 3.3V Schmitt trigger input.  The datasheet shows a hysteresis voltage of 400 mV for Vccio = 3.3V, but it does not specify that actual trip points, or at least the center point.

[FvM]

Hi,

unfortunately MAX V datasheet (neither other CPLD or FPFA datasheets) give typical threshold voltage for 3.3V IO-standard, you can assume that it's somewhere between Vil,max of 0.8 V and Vih,min of 1.7 V. 3.3V ST thresholds have in case of doubt +/- offset to lvcmos33.

To evaluate typical ST thresholds, you'll need to make your own measurements. You can e.g. setup a slow RC ST oscillator and measure reversal points.

[griffin1701]

Thanks for the info.  We decided to perform the measurements ourselves, as you recommended.

[AqidAyman_Intel · Accepted solution]

Thank you for the input, Frank.

Do you have any more help needed on this issue?

[AqidAyman_Intel]

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