Feedback on D24V5Fx

Just a minor FYI feedback on the D24V5x voltage regulator.

I used a couple of D24V5Fx regulators in place of D24V6Fx which I had used before and was caught out by your addition of a 100k pull-up on the SHDN pin of an otherwise functionally identical product.

I understand why you did it but I like to use multiple little regulators as an easy way to turn parts of a project on and off. To stay off while a micro’s pin is high-impedance, I need a pull-down of ~1k, at 24v input. That in turn takes ~5mA to pull back up to 5v when the micro pin goes high! (BTW these regulators can be a bit iffy until the SHDN pin is well above the spec’d 0.4v.)

The easy fix for me was to switch back to the D24V6Fx, but I would have preferred if you hadn’t assumed how these would be used. After all, the Vin & Gnd pins are right next to SHDN; no hardship to add a pull-up or pull-down.

Just FYI.


PS. I love these voltage regulators, by the way, I’ve bought dozens (especially in your sales!:slight_smile:

Hi, Martin.

Thank you for the compliments and feedback about our regulators. The older D24V6Fx units default to being on, too; the difference with the newer D24V5Fx units is that we used stronger pull-ups to avoid some of the inconsistent performance customers sometimes saw when leaving the enable line floating.

Regarding your comment about our assumptions, we think it is important to make those assumptions to make our products good. Of course it did not work out for you in this instance, but engineering and product design is a lot about trade-offs, and making the right calls involves thinking about how people will use the products. For your case, I hope it’s not too much trouble to remove the resistor, which I have circled in the picture below. If you ever need higher volumes, we can make them for you without the resistors.