I’m not sure, but these MBR230LSFT1G diodes may be defective. I measured with the diode/continuity setting on my multimeter and got OL (while blinking, unexpected) forward voltage and OL (non blinking) reverse (expected).
When measuring a different Schottky (BAT53WS-7-F) I get 0.25 forward and OL reverse.
In my circuit I’m seeing voltage leak (reverse conduction) from the cathode to the anode (4.12v on cathode, 2.24v on anode which should be 0v) which got me to check other diodes from the same tape. Using the 200K resistance range on the meter I’m seeing 8.7K reverse and 2.0K forward measurements on 2 diodes I tested straight out of the tape.
Like I said, I’m not sure if I’m just making a mistake, but I was struggling debugging this circuit for a while before finally suspecting the diode. Thanks for any suggestions on what I should test
Lot code: QB25135.U1
Hello MindsForge,
Welcome to the DigiKey TechForum! This is a bit of a tough one, as troubleshooting failures in a circuit can be tricky since there can be so many causes of the known failure, including compounding failures that are unknown. I find your DMM giving OL in both directions suspect, though. I know you did the resistance test to the two parts straight out of the tape; did you happen to do the diode continuity test to those as well? If you did and got the same results as before, then it is indeed likely that the diodes are defective.
Regards,
Klint
Yep, just repeated the continuity/diode test on the 2 from the tape and got the same blinking OL response from the meter (and just removed and tested a 3rd, same issue)
Factory defect is typically a conclusion of last resort. Component manufacturers that let more than a few per million out the door don’t usually stay in business very long, and the chances of something else going sideways afterward are much higher, particularly in a developmental/experimental context.
Check the device marking, per the datasheet it should be L3N.
Info as to what meter you’re using may be helpful; they do vary in their particulars and the MBR230 diodes are rather more leaky than some.
I agree with manufacture defect being last suspicion, the markings are correct “L3N C”
The meter is unfortunately a cheaper one, DT9208A – but I did compare reading with another Schottky and got an expected result
The application circuit is actually “Oring” between battery and USB VBUS
You might want to consider another diode with significantly less reverse leakage, something like the following two diodes:
CRS20I30B(TE85L,QM
FSL23S
2 Likes
Thanks, I’ll give those a shot
