I am working on a medical device. I want to FDA certification for it. The device is having ePHI (protected health information). So is it mandatory to have HIPAA compliance for FDA approval?
I think the FDA will require HIPAA compliance for any device that uses PHI -- but, as has been noted in the comments to your question, the FDA will be the sole authority on its own requirements. This question-and-answer site is designed to provide helpful guidance -- but what you need is a legal opinion.
That said, even if you find that HIPAA compliance is not mandatory for the device you are working on, your only wise choice is to build on a foundation of HIPAA compliance anyway. This is especially important since you're already working with PHI. (And it would still be important even if you weren't, to allow for growth of your product.)