DAC6311 - overshoot and undershoot at the digital pins

Hello Asaka-san,

Ryuji Asaka said:

Question 1 .
Can the DAC6311 accept this undershoot ?

Yes. The DAC6311 has an ESD diode to GND that will conduct due to this undershoot. It will not affect the performance of the DAC. The AC ratings can only be guaranteed to be the same as the DC ratings. Keep in mind that these Abs Max ratings hold across temperature as well, meaning that there is some headroom if the part is only being used at room temperature. This headroom is something that cannot be guaranteed by TI at a specific temperature, only across the entire temperature span.

Ryuji Asaka said:

Question 2.
Could you please let me know the AC absolute maximum ratings for overshoot?

The AC ratings can only be guaranteed to be the same as the DC ratings. For undershoot, the conduction to GND will not affect the performance of the device. The overshoot, can affect the performance of the DAC. There is also an ESD diode to AVDD which will conduct if the overshoot it too large, the output can begin to show show large digital feedthrough. For the 8-bit DAC6311, this will probably be a very minor issue.

• What is the frequency of the CLK you are using?
• Would it be acceptable to slow this down using a passive R or C?
• What is the maximum glitch allowed at the output?

Ryuji Asaka said:

And the undershoot voltage in the waveform which I attached is about -3.6V.
I understood that the DAC6311 accept this undershoot since DAC6311 has ESD diode

The undershoot in the waveform that you attached is -0.36 V, not -3.6 V correct?

The DAC6311 performance will not be affected by an undershoot in the digital supplies of -0.36 V at 25 °C. The ESD diode will allow current to flow to GND from the DIO. If the undershoot is too large, it is possible that it may instantaneously charge the GND to a voltage lower than 0 V. Please try to minimize the undershoot as much as possible to avoid charging the GND to a voltage different than 0 V, as this may affect other devices around your system.