What is this SOT23-5 please - Page 1
Forum section: electronics / repair

author: cybermaus
author_rank: Frequent Contributor
timestamp: January 29, 2023, 07:47:45 pm
content: I tried searching some SMD code bases, but I am not finding many DG at allThe item is on a camera sensor sub-board, and frankly the only reason it is suspect at all because it is the only one where I do not measure any junction pin 4(red on ground, diode test method) All other SOT23-5 and all other diodes and capacitors measure OK.I have to admit, it it is a bit if a last-ditch effort.

author: fzabkar
author_rank: Super Contributor
timestamp: January 29, 2023, 08:06:56 pm
content: Could it be an RT9178-30CBR 3.0V LDO regulator?http://www.smdmark.com/en-US/search/code?id=dghttps://www.richtek.com/assets/product_file/RT9178/DS9178-19.pdf

author: mikerj
author_rank: Super Contributor
timestamp: January 29, 2023, 08:08:40 pm
content: How old is the camera? The code and marking match a V6310 reset controller, but it's an old part long out of production.https://www.datasheets.com/en/part-details/v6310rsp5b--em-microelectronic-20195197

author: cybermaus
author_rank: Frequent Contributor
timestamp: January 29, 2023, 09:03:00 pm
content: Thanks. It's an IP camera from about 2012a high speed dome PTZ superzoom, so not entirely cheap.fzabkar : A regulator at this location is unlikely. I would more expect some single logic gate.Also, I do not see the marking in your suggested PDF?mikerj :It's unlikely to be the device you suggest, because while Vss seems to be correct, I have a junctions on what on your suggestion should be NC pins.Also, but this may be my unfamiliarity with SMD codes, but your PDF shows DG# for 3-letter code option, but a completely different 4-letter code option, and I have a 4 letter code.

author: fzabkar
author_rank: Super Contributor
timestamp: January 29, 2023, 09:20:58 pm
content: Quote from: cybermaus on January 29, 2023, 09:03:00 pmThe markings are not published in the PDF. They were provided by the smd part marking database.Can you measure the voltages on the pins?Are there 3 capacitors connected to this chip? If so, then that would be inconsistent with a logic gate, but would make perfect sense for an LDO.Can you show us a photo of the whole PCB? Often it is better to see the part in context. Also, it may help to identify this chip if we can identify other chips. Often a designer will use a single source.

author: cybermaus
author_rank: Frequent Contributor
timestamp: January 29, 2023, 09:28:21 pm
content: I see what you mean with the 3 capacitors, good point, I'll go check.But the code in the database is only DG. 2 chars out of 4 seems a bit broad.Unless of course if you see more because you are signed in? All I see is: "DG" "Please login" SOT23-5

author: fzabkar
author_rank: Super Contributor
timestamp: January 29, 2023, 09:35:54 pm
content: Quote from: cybermaus on January 29, 2023, 09:28:21 pmChips often have additional markings. "DG" could be the part ID, while "5" could be a year, and "v" could be a batch code.The PDF icon has this URL:https://www.onepcba.com/p/RT9178-30CBR

author: timenutgoblin
author_rank: Regular Contributor
timestamp: January 29, 2023, 10:06:25 pm
content: I also think it's an LDO voltage regulator. There are bypass and decoupling capacitors.See attachment below for pinout suggestion:

author: cybermaus
author_rank: Frequent Contributor
timestamp: January 29, 2023, 10:50:04 pm
content: Yes @fzabkar and @timenutgoblinIt is indeed a LDO. The capacitors, as well as the 10K pullup resistor make it extra likely.Also I figured out it came from a 5V switched regulator upstream, and injecting voltage there showed another short on another part of the board, causing this LDO to be starved.

author: fzabkar
author_rank: Super Contributor
timestamp: January 30, 2023, 03:39:05 am
content: There is a similar LDO here, but "DG" is associated with a 1.8V regulator in a different package.https://www.vishay.com/docs/74442/sip21106.pdfThis "DG" part is a 2.1V LDO in a SOT23-5 package:https://pdf.datasheet.live/29eb28f9/anachip.com.tw/AP131-33WA.pdf

author: cybermaus
author_rank: Frequent Contributor
timestamp: January 30, 2023, 02:54:59 pm
content: It is definitely and indeed a regulator, with the above common pinout, and it makes 2.85V out of 5V, and it is still in working order.In the mean time I traced the problem to another chip that is shorting, and the camera is a loss.Thanks everyone.