[SI-LIST] Re: Question about transistors.
- From: "lgreen" <lgreen22@xxxxxxxxxxxxxx>
- To: <jomeshpa@xxxxxxxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Wed, 15 Dec 2004 21:06:34 -0800
Hello, Jomesh,
Your best bet would be to get a transistor with a higher current rating. At
large currents, there are a number of limitations.
1) The bond wire acts as a fuse (i.e. transistor fails in open circuit
mode).
2) For large Vce, the collector junction can literally punch through the
base, shorting the emitter to the collector. (i.e. transistor fails in
short-circuit mode.)
3) The junction temperature (determined by Ic*Vce) can be much higher than
ambient, even if you are able to cool the external package. Transistor can
enter thermal run-away, leading to actual damage to the junction doping
profile. Worst case, the silicon can actually melt, crack the package, and
leave a pit in the silicon chip (I have seen this, and it is quite
impressive).
Best regards,
Lynne
"IBIS training when you need it, where you need it."
Dr. Lynne Green
Green Streak Programs
http://www.greenstreakprograms.com
425-788-0412
lgreen22@xxxxxxxxxxxxxx
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Jomesh P A
Sent: Wednesday, December 15, 2004 8:30 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Question about transistors.
Hi experts,Sorry, its not exactly an SI Question, but can anybody help me?I
have a doubt in the specifications of a transistor. The datasheet says an
absolute maximum collector current of 1A. But if we provide sufficient
cooling, can we use it to carry higher currents? Also, the datasheet says
the transistor has an hfe of 25 for IC = 150mA and VCE = 2V. To design a
switch using this transistor with a load of approximately 1A, what could be
the best Bdc to assume???Thanks in advance.Jomesh
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
