You guys are going to think I hate you or have a vendetta and I honestly do not. I am not sure why I keep having troubles with your parts. I am not having this sort of trouble with other components. I have 7 different micro-controller projects with about 50 purchased parts between them and I have had 4 part failures. 3 of them have been the 3 Pololu parts I bought. I may not be a full engineer and don’t always use best practices, but I mostly know what I am doing.
Anyway, I have been using 7.4 LiPos with the D15V35F5S3 to provide 5v VCC to a micro-controller. It has been working fine. In order to try to cut down on the number of power sources, I tried using 12v as I have an SLA on board that is powering a sonar unit (that is the unit with RS-232, BTW, so there is a data line from something on the same battery feeding into a level shifter). The board powered on but the D15V35F5S3 made a loud pop and a puff of smoke rose from the middle of the board. I disconnected power immediately though it was still supplying power to the micro. I wated a few minutes for things to cool and caps to discharge and plugged in a 7.4v LiPo again. it still seems to work fine.
I used Deans keyed connectors and the polarity was correct. Like I said, it did actually provide power to the board. Could it be the data line causing some bizarre feedback loop? I do similar things on other projects (not using the D15V35F5S3 and at lower voltage) where I use a 4.8v battery as VIN to 3.3v micros which have on board regulators beefy enough for what I have them doing and power a GPS on the 4.8v that provides TTL serial data to the micro and that doesn’t cause a problem.
Can you describe your “data line” connections in detail? Is it possible that you had the 5V output shorted either to ground or to some other voltage from another component?
The data line was the sonar unit’s Tx line, which is RS-232. It is running to an SFE RS-232 to TTL level shifter (I got that to replace the DOA 23201a). It was working fine before the VR blew and is working fine now that the VR has been replaced with a BEC. The VR was working fine for several days getting voltage of 7.4v and only blew when it got 12v, though it was supplying power as it smoked. Anyway, the sonar is running on the same 12v power that was used as input to the VR. Turns out the level shifter makes that irrelevant; sorry I mentioned it. Didn’t mean to confuse the issue.
Why do you say the level shifter is irrelevant? We cannot help you figure out what might have gone wrong without knowing what was connected when the device broke. Anyway, it is hard to tell from your description exactly what you were doing - if you want more help with it, could you post a picture and a schematic?
It is irrelevant because the input data line of the level shifter is the only thing that was seeing the 12v RS-232 and its purpose is to isolate and adjust that. Besides, the base problem here is that it was working with one voltage and then blew with a higher voltage that was still well within its documented input range. Schematic? The 5v output was going directly to the VCC of an Arduino MEGA. The Arduino is working fine as are all other components powered by something else for the time being.
You seem to be saying that if the 5V output goes into an Arduino and the Arduino does not break, that implies that there was nothing wrong with your circuit. That reasoning is just not valid. Like I said, if you do not give us the details, there is nothing that we can do for you.
On second thought, “wrong with your circuit” was a little too strong. Because even if there is some problem with our board, we cannot identify it without knowing what you were doing. If you just tell us that it smoked at 12V, we are going to compare you to all of our other customers who have it working at 12V and assume that you probably did something wrong. But if you give us a really specific combination of parts that caused it to smoke, that sets you apart from all of our other customers and gives us something to analyze theoretically and experimentally.
You even specifically asked about a “bizarre feedback loop” in your first post - do you expect us to be able to address that possibility without even seeing the circuit?
