D15V35F5S3 output double what is expected


I have a new D15V35F5S3 step-down regulator. I tested it before connecting to an expensive VGA frame-grabber, and found it’s outputting about double the expected voltage.

When 3V3SEL is open-circuit I get ~10.2V between VOUT and GND (measured with my Fluke 177).
When 3V3SEL is bridged, I get ~6.4V between VOUT and GND.
VIN is at 12.8V according to the same Fluke DVM. The Fluke agrees to within <0.1V with the digital meter on the 40A bench supply I’m using to supply the power, so I’m pretty confident the Fluke’s right.

I get very similar results whether unloaded or when loaded with a small 12V DC motor (all I have to hand just now.) The circuit is very simple - the only connection not mentioned so far is that I have EN connected to VIN.

Has anyone else come across this?
I want to use the 5V-powered frame-grabber on a boat that only has 12VDC, no AC and no safely dry place to put an inverter, but should I be trusting $1,000 worth of frame-grabber to this reg, or am I being foolish?


Hello, Tom.

I am sorry you are having trouble with your regulator. We have not had any other reports of this happening. Thank you for posting clear details of what you did to test it. Could you also please post picture of the component side of your board (one that is good enough for us to read the component values)?

- Emily