ISO6763-Q1: Maximum output capacitance, Internal carrier signal frequency, EMI-EMC improvement

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Thank you for reaching out.
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Regards,
Aaditya V

Hi Sanket,

Thanks for reaching out. Please see the answers below: 

Sanket Walopkar said:

For most of the timing parameters, load capacitance CL is mentioned as 15pF.

But what is the maximum value of load capacitance I can connect at the output of the isolator.

This mainly depends on the absolute maximum ratings for output current, which is -15mA to 15mA, and the input frequency as well. Therefore, this mainly depends on the parameters you set in your system to select a load capacitor.

Sanket Walopkar said:

For internal on-off keying based operation,

What is the carrier frequency used, is there any tolerance to this frequency?

The OOK frequency is around 450MHz.

Sanket Walopkar said:

For EMI-EMC related improvement:

Is it recommended to have an external capacitance between 2 grounds?

Yes, for EMC and EMI relatewd improvements, a y-cap (>100pF) across the isolation barrier. This means that the y-cap can be connected between GND1 and GND2.

Regards,
Aaditya Vittal

Hello Aditya,

For maximum CL,

how to select the capacitor value, based on output current and input frequency?

Can you please provide a reference calculation?

Thanks,

Sanket

Hi Sanket,

Since CL simulates the connection of an MCU to the isolator, CL is not used in a system. Can you please provide information on why you would like to use CL calculation?

Regards,
Aaditya