Equivalent for TI TIP54 transistor (3A variant) - Page 1
Forum section: electronics / beginners

author: giosif
author_rank: Frequent Contributor
timestamp: February 06, 2017, 03:45:19 pm
content: Hi,Another episode in my adventure trying to get a Solartron 7075 DMM to work reliably: the power supply has died again.This time, the TI TIP54 transistor (TO-218AA package - 3A continuous current; 5A peak current) went out with a bang and I am looking for a suitable replacement.So far, the only match I found was the NTE394, but that seems to be obsolete as well.Anyone has any suggestions, please?In my search, I found the Fairchild FJA13009TU, and it is available, but I'm not sure it is a proper replacement.And, yes, I am aware of the TIP54's available on eBay, but I've already had my share of attempts with those.Thanks!

author: alsetalokin4017
author_rank: Super Contributor
timestamp: February 06, 2017, 04:34:17 pm
content: BUL118 ?ST13005N ?"Obsolete" doesn't mean unobtainable, necessarily.

author: giosif
author_rank: Frequent Contributor
timestamp: February 06, 2017, 07:06:37 pm
content: Hmm...I should have specified that power dissipation should be 100W with a heatsink.The two transistors you mention don't meet that spec.

author: David Hess
author_rank: Super Contributor
timestamp: February 07, 2017, 12:57:59 am
content: TR6 is being used as the power switch in a high voltage buck switching regulator and not as a linear pass element so it does not need to be 100 watts.

author: crazyguy
author_rank: Regular Contributor
timestamp: February 07, 2017, 07:38:37 am
content: STMicroelectronics BU508AW NPN Transistor, 8 A, 700 V, 3-Pin TO-247http://www.st.com/content/ccc/resource/technical/document/datasheet/93/58/50/ef/30/7c/4c/09/CD00153828.pdf/files/CD00153828.pdf/jcr:content/translations/en.CD00153828.pdf

author: mikerj
author_rank: Super Contributor
timestamp: February 07, 2017, 08:37:01 am
content: Switching devices hardly ever just fail by themselves, it's almost always caused by failure of another component that results in them being driven incorrectly e.g. bad cap, bad solder joint etc. so ensure you find out why it dies before replacing it.BU508 maybe not the best choice as current gain is quite a bit lower than the TIP54. It may be easier to find a suitable part in a TO220 footprint, the pin-out is the same but will require leads to be formed etc.

author: giosif
author_rank: Frequent Contributor
timestamp: February 07, 2017, 09:34:39 am
content: Quote from: David Hess on February 07, 2017, 12:57:59 amGot it.Me not really understanding the entire circuit, I am normally going with the "like-for-like replacement" approach.Thanks for the explanation!

author: rsjsouza
author_rank: Super Contributor
timestamp: February 07, 2017, 11:29:57 am
content: Doesthis listing on ebayhelp?

author: David Hess
author_rank: Super Contributor
timestamp: February 07, 2017, 08:24:26 pm
content: Quote from: mikerj on February 07, 2017, 08:37:01 amI agree on both counts.While it is possible that the power switch failed by itself, even that could damage other circuits so they need to be checked anyway.I also would look for a TO-220 replacement part simply because the variety is better and the cost is lower. Pay attention to hfe and switching time.