ON Semi MJ21193 / MJ21194 'perforated emitter' power transistors? - Page 1
Forum section: electronics / projects

author: cvanc
author_rank: Frequent Contributor
timestamp: January 16, 2018, 12:28:51 pm
content: http://www.onsemi.com/pub/Collateral/MJ21193-D.PDFhttps://www.onsemi.com/pub/Collateral/TND333-D.PDFAnyone here with experience using these 'perforated emitter' transistors? If you look at the die photos in the white paper it's sort-of kind-of a bunch of B-E junctions in parallel sharing a single collector. Cool.They read well for use in older audio gear that needs TO-3 output devices.Thanks.

author: rfeecs
author_rank: Frequent Contributor
timestamp: January 16, 2018, 07:53:13 pm
content: It seems to be something like this:https://www.google.com/patents/EP2458639A1?cl=enQuote

author: rfeecs
author_rank: Frequent Contributor
timestamp: January 16, 2018, 10:59:10 pm
content: A couple of other (similar?) interesting die pictures from Zeptobars:https://zeptobars.com/en/read/OnSemi-MMBT2222A-MMBT2222AL1G-npn-bjt-transistorhttps://zeptobars.com/en/read/ST-2STD1665-NPN-BJT

author: David Hess
author_rank: Super Contributor
timestamp: January 17, 2018, 05:10:14 am
content: Perforated or ring emitter transistors have increased secondary breakdown safe operating area, flatter and better hfe, and flatter and better Ft.

author: John Heath
author_rank: Frequent Contributor
timestamp: January 17, 2018, 08:02:40 am
content: There was an effort to make carbon doped output transistors at one time. The advantage was they could run almost red hot without damage from melting. At almost red hot a big heat sink is just a tiny heat sink as thermal energy desipation is the square of the temperature difference. For some reason it never caught on so you don't hear of it anymore?

author: David Hess
author_rank: Super Contributor
timestamp: January 17, 2018, 01:35:24 pm
content: Quote from: John Heath on January 17, 2018, 08:02:40 amSilicon carbide semiconductors have that advantage; they can operate at higher junction temperatures so a greater junction to ambient thermal resistance can dissipate more power. In most cases this means that a smaller semiconductor die can handle higher power.

author: John Heath
author_rank: Frequent Contributor
timestamp: January 18, 2018, 04:25:37 pm
content: Quote from: David Hess on January 17, 2018, 01:35:24 pmThey are still around. It did not fade away into history. I found a video on silicon carbide diodes.

author: rfeecs
author_rank: Frequent Contributor
timestamp: January 18, 2018, 05:31:54 pm
content: SiC is not just used in diodes.Cree (Wolfspeed) SiC MOSFETs:https://www.wolfspeed.com/power/products/sic-mosfetsSiC is also used as a substrate for GaN FETs and LEDs.

author: David Hess
author_rank: Super Contributor
timestamp: January 19, 2018, 12:19:05 am
content: Quote from: John Heath on January 18, 2018, 04:25:37 pmSilicon carbide is also use in high temperature small signal applications like signal conditioning and logic.

author: DrGonzoDK
author_rank: Regular Contributor
timestamp: January 20, 2018, 09:44:54 am
content: Quote from: rfeecs on January 18, 2018, 05:31:54 pmIndeed, it is also used for a new series of SiC power switching JFETs -http://unitedsic.com/wp-content/uploads/2017/01/DS_UJN1205K.pdfThe UJN1205K is a mean motherf*cker and just arrived on Mouser. Can't wait 'till my order arrives...