Chosen Solution
Hi, I need to fix my led aquarium lights that has a damaged sot23 transistor but need help in determining the correct part to order. As per the pic their is a marking of B28W and the transistor sits right next to a 0 ohm resistor and a cap.
Hi John, Man, talk about going down the rabbit hole on this one! I wandered some pretty far flung corners of the internet poking around looking for SMD marking codes. A big problem here is that apparently a lot of manufacturers only use like one or two letters for a part identification, and the rest may well be year, work week and/or lot code. The most promising lead I found was a PDF for something called Micro3 (company name, maybe?) that gave their package markings. Under the SOT-23 page, a table indicated specific part numbers associated with only the first digit, “B”, saying the part number for that is IRLML2803. 01-0041 Version 37, MARKING PACKAGES Model (1)
As you can see in the image, the next two digits are year and week, which would say that the second part, B2Y7 was made in 2002 or 2012 (and depending on how out of date that PDF is, possibly 2022) in work week 25 with a Lot Code of 7. This would indicate that the two parts are actually the same; they just have different manufacturing dates, which would make a certain amount of sense. Unfortunately, the decoding breaks down on the first part, the damaged one, since the work week code on that one is an 8, and according to that PDF file it should be alphabetic (A-Z), so I have no idea what that means; possibly that I’ve chased that rabbit into a maze and lost it completely, lol. Anyway, a search for IRLML2803 came up with a part identified as MOSFET MOSFT 30V 1.2A 250mOhm 3.3nC LogLvl on mouser.com, which would make sense for that part, but who knows? IRLML2803TRPBF Infineon Technologies That’s all I got for ya; dunno if it’s going to be a help or just a distraction, but there you go. Good luck; let us know how it goes!
Hi John, Sorry to start another answer, but I wanted to add to what we’ve been talking about. I found a data sheet for one of the Microchip products that looks interesting. 11AAXXX/11LCXXX Data Sheet When I scrolled down the the package marking section, guess what I found?
According to that, the first two characters, B2 designate the part, and the last two are some sort of “Alphanumeric traceability code”. B2 corresponds to part number 11AA020 that’s referred to on the Mouser site as EEPROM 2K 256X8 1.8V SERIAL EE IND. 11AA020T-I/TT Microchip Technology So if that’s the right part, you should see 1.8V across pins 2 and 3. I’d power up the good board you have and stick a voltmeter on there and see what you get.
EDIT: Actually, according to the data sheet, that part can run with a wide voltage range, anywhere from 1.8-5.5V.
