SM Switching Regulator Identification - Page 1
Forum section: electronics / repair

author: Mike Warren
author_rank: Unknown
timestamp: June 20, 2021, 10:12:36 pm
content: I have a couple of Seagate portable hard drives, both have a dead SM buck switching regulator that I am not having any luck Googling.It's in a SOT23-6 package.The Markings are FF7RNF and FF7IBT so I'm guessing the IC type is the FF7 and the other 3 characters are the batch.There are 3 of these chips in each unit, which helped me confirm that one in each unit was dead. I'm guessing a power spike killed them. By swapping a good one in one board to the other board got it working perfectly.The values in the schematic below are what I measured in circuit.

author: fzabkar
author_rank: Super Contributor
timestamp: June 20, 2021, 10:32:23 pm
content: I have a database of HDD/SSD ICs:http://www.users.on.net/~fzabkar/Datasheets/DATAURLS.HTMIf your device isn't listed, you could examine photos of the same PCB in case they have equivalent parts.Am I correct in thinking that this component is on the USB-SATA bridge PCB?Edit: This looks like it might be a good fit, but its FB voltage is 0.6V whereas your circuit would suggest that it should be 2.5V.VB9113, VBCSEMICON Technology, 3A, 4.5V - 21V Input, 500kHz, marking FF7, SOT23-6:http://www.vbcsemicon.com/upload/pdf/VB9113-v3.0.pdfHere is another 0.6V candidate:FR8205, Fitipower, 18V, 3A, 500KHz Synchronous Step-Down DC/DC Converter, marking FF7, SOT23-6:https://datasheet.lcsc.com/szlcsc/Fitipower-Integrated-Tech-FR8205S6CTR_C172764.pdfhttps://www.aliexpress.com/item/1005001992210575.html

author: Mike Warren
author_rank: Unknown
timestamp: June 20, 2021, 11:12:41 pm
content: Thanks for your reply.Quote from: fzabkar on June 20, 2021, 10:32:23 pmYes.QuoteThanks. They are closer than anything I found. I'll go back and check the feedback resistors again in case I made a mistake.

author: Mike Warren
author_rank: Unknown
timestamp: June 20, 2021, 11:27:46 pm
content: Yes, I did make a mistake. The feedback voltage is 0.6V.The trick now is to find somewhere to buy them. Mouser, Digikey, E14, RS and Alibaba have no matches for either one and Google thinks one of them is a pair of cowboy boots and the other is a Ryanair flight.Edit: I see you updated your post with an AliExpress link. Thanks.Edit 2: Purchased. $44 for FedX shipping! Ouch!

author: fzabkar
author_rank: Super Contributor
timestamp: June 21, 2021, 12:56:52 am
content: It would have been far cheaper to purchase a generic enclosure???

author: Mike Warren
author_rank: Unknown
timestamp: June 21, 2021, 01:04:56 am
content: Quote from: fzabkar on June 21, 2021, 12:56:52 amThen my OCD would be aggravated that my stack of backup drive weren't the same type.

author: Mike Warren
author_rank: Unknown
timestamp: June 24, 2021, 09:40:28 pm
content: Hmmm.When I placed the order, 5 days ago, there was a counter that said the order would be automatically cancelled if it was not shipped within 7 days.I just checked and the order is still not shipped, but the counter now says the seller has 5 days and 2 hours to ship. Looks like AliExpress must be working to a different clock.I've only bought a couple of things from AliExpress and they both went fine, but this does not inspire confidence.Edit: Ah, found another place where the days are specified as "business days". That's not stated anywhere near the countdown clock.