If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #190
Joined: Fri Feb 17 2006, 12:00AM
Location:
Posts: 1567
Many high current devices (igbt, mosfets, diodes) have one of the terminals connected to the metal casing and a through-hole pin. THis casing gets mounted to a heatsink. Is there any difference with regards to heat dissipation or conduction if one connects the circuit to the case or the pin lead?
Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
Look at the data sheet, different devices use different standards. Some say you can connect electrically through the heat tab, some say you must put all the current through the pin, but keep the heat tab at the same potential. If there's 10s or 100s of amps involved, then I guess it's a smart idea to do what the data sheet says.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
I've always treated the tab and the centre pin as interchangeable. They're both physically the same piece of metal, and the silicon die is attached to it by solder that carries both the heat and the current away.
I've built high-current circuits where TO220 MOSFETs were clamped by their tabs to a busbar that carried the current and acted as a heatsink. I cut the centre pins off.
In some power ICs, there may not be any pin that's a physical part of the tab, and I guess this is the scenario where Dr. Slack says all the current must go through the pin. But this isn't the case for any MOSFET, BJT or IGBT in a 3-pin TO220 or TO247 that I know of.
In a TO-3 the case is the collector, but the tab/pin thing is really the same as that.
Edit: With diodes it gets a bit more complicated. Some high voltage diodes come in two-pin TO247s, and are made of two diodes in series internally. I wouldn't be surprised if the tab was connected to the centre point of the two diodes.
Registered Member #1408
Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679
Steve McConner wrote ...
In some power ICs, there may not be any pin that's a physical part of the tab, and I guess this is the scenario where Dr. Slack says all the current must go through the pin. But this isn't the case for any MOSFET, BJT or IGBT in a 3-pin TO220 or TO247 that I know of.
An exception I found was on one of the more powerful IGBT's that I know of: the Toshiba GT60N321 is a TO-247 case but the metallic back is covered so it demands that you use the pins. This is a sweet transistor with 1K collector-emitter voltage, collector current 60A, at 170W. I used it before on several projects & it was always worth hunting for or buying from Mouser. It's like a tank!
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
connecting high current semiconductors to heatsinks
