View Full Version : IRS2113 SD pin noise sensitivity

Feb 2nd, 2019, 08:53 AM
Just a note for other users, I recently changed from using an IRS2110 (lower floating voltage version) and encountered a persistent fault in an H-bridge
where it looked like high side UVLO (the high side just stopped working) even though the low side continued working. I spent ages scoping the high side
and changing components in the boost circuit to no avail. Eventually in desperation I grounded the previously floating Sd pin and the fault went away!
I should emphasize this was a swap from an IRS2110 to an IRS2113 in the same pcb in a previously working circuit. Both date codes concerned 713P
so it seems maybe I was lucky before or the 2113 is more sensitive, in either case I would never rely on the internal pulldowns again.

Has this site never heard of an editor that wraps!

Feb 4th, 2019, 01:08 PM
What is the VDD and VCC voltage in your design?

The Sd pin has a weak pull down internally. It is recommended to ground the pin if unused.

Feb 8th, 2019, 03:41 AM
Hello, my VCC is 12V & VDD is 3V3.

Unfortunately the data sheet implies grounding is unnecessary and I think I left it floating for future use however on closer inspection of the data sheet it seems the pulldown resistance is undefined! At best there is a TYPICAL value for input leakage but no minimum.....