I'm trying to implement an Exar XRP7659 on a breadboard to step 17V to 5V @ 1.5A. The regulator is rated for 18v. Now, I have the circuit wired up and initially the output voltage is 5V on the regulator but after I add load (a phone to charge via USB) the voltage drops to 3.25V and then spikes to ~16V (presumably fried because it won't step to 5V anymore). I even had one regulator catch on fire! As far as my components, all resistors are 1% except for the 100k EN resistor. The capacitors are all ceramic as well.

Here's the regulators application guide for 5V: Regulator Application @ 5V

Here's my breadboard's layout with labels: Regulator on breadboard

Any idea what I'm doing to destroy these regulators?



1 Answer 1


It looks like you misplaced the feedback resistors. They are tapping off the wrong end of the inductor.

Making a switched regulator on a breadboard is asking for trouble. If you check the manufacturers demo board layout you see that its nowhere near this type of breadboard layout. With this you will have stray capacitances, messy ground paths to mention some of the problems.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.