FET identification? - Page 1
Forum section: electronics / projects

author: andrewbostaph
author_rank: Newbie
timestamp: June 05, 2018, 10:37:33 am
content: Hi everyoneAnyone know what FET this might be? Appears to be SOT-23 in size. Most likely an NPN and pin 2 is connected to GND. After a search online looking at SMD codes etc etc found nothing.Cheers!

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: June 05, 2018, 10:55:14 am
content: 1A on SOT-23 would point towards NPN transistor.http://www.s-manuals.com/smd/1ahttp://www.sphere.bc.ca/download/smd-codebook.pdfHowever, exclamation mark does not ring a bell.You might be better of with a schematic to get the right specs in case this needs to be replaced.

author: Simon
author_rank: Unknown
timestamp: June 05, 2018, 11:51:57 am
content: Very difficult. This is the downside to SMD you will never know what it is unless it is a well known part or the number is a give away.

author: andrewbostaph
author_rank: Newbie
timestamp: June 05, 2018, 12:02:34 pm
content: Since FET 1 appears to be an IRLML6401 according to some SMD codes online FET 2 maybe an IRLML2402 but the datasheets show something a little different. The exclamation mark has got me stumped.

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: June 05, 2018, 01:01:46 pm
content: Also this:https://www.fairchildsemi.com.cn/Assets/-topmark/pinOne.ssiWhere the exclamation point marks pin 1 and the dashes somehow represent date codes. (?)1A V does not ring a bell still.Edit: The marking might very well be just "1A"."V" and the Cyrillic looking "г" »Ghe« maybe are some manufacturer IDs?The date code from the dashes above would read 101 and 100 representing 5 and 4, so I would guess 2005 and 2004 - just to get that out of the equationIf you can share more info on the actual circuit it sits in, we might be better of just selecting a proper part for the circuit, than blindly poking at those markings.

author: andrewbostaph
author_rank: Newbie
timestamp: June 05, 2018, 10:42:07 pm
content: The "V" and "г" is probably the date of manufacture. The 2 lines above the A and V will also indicate something else.

author: andrewbostaph
author_rank: Newbie
timestamp: June 05, 2018, 10:44:38 pm
content: Interesting markings from that link!

author: Jwillis
author_rank: Super Contributor
timestamp: June 06, 2018, 09:39:47 am
content: SOT (small outline transistor) 23 1A is a BC846A or equivalent like BC846AT,BC546A,2N3904 if its Philips, Motorola or Zetex . Intentional rectifier 1A is a n ch mosfet 20V 0.9A IRLML2402The actual dimensions of the package makes a difference as well SOT 23 ,SOT 323 ,SOT 416 ,SC 59 ,SC 70 and SC 90 like very much alike but have varying dimensions. But The 1A comes in SOT 23 ,SOT 416 and SOT 323

author: andrewbostaph
author_rank: Newbie
timestamp: June 06, 2018, 10:06:58 am
content: Turns out that its a Fairchild MMBT3904. Google "Fairchild sot23 markings" click on images and you will see that other components also use the "!" before the code marking The line in the "!" indicates the factory that manufactured the component and the dot underneath indicates PIN 1.https://www.fairchildsemi.com.cn/Assets/-topmark/pinOne.ssi