[SI-LIST] Re: current rating of wirebonds
- From: John Barnes <jrbarnes@xxxxxxxxx>
- To: jan.vercammen1@xxxxxxxx, si-list@xxxxxxxxxxxxx
- Date: Fri, 21 Mar 2003 10:39:14 -0500
Jan,
Page 18 of MIL-M-38510J, "Military Specification Microcircuits
General Specifications for," dated 15 November 1991 shows (W. H.
Preece's) equation
I = K * d^1.5
with the following table:
Composition "K" values for bond-to-bond total conductor length
Length <= 0.040" (0.1cm) Length > 0.040" (0.1cm)
-------------- ------------------------ -----------------------
Aluminum 22,000 15,200
Gold 30,000 20,500
Copper 30,000 20,500
Silver 15,000 10,500
All others 9,000 6,300
You can download MIL-M-38510J (and many other US miltary standards) for
free from DODSSP ( http://www.dodssp.daps.mil/ ), although they
now require you to register, and it may take a couple of days to get
your account name and password from them.
I've seen Preece's Equation presented in a number of books with the
following K values:
Material K in A/inch^1.5
---------------------- -------------------
Copper 10,244
Aluminum 7,585
German Silver 5,230
Platinum 5,172
Platinoid 4,750
Iron 3,148
Tin 1,642
Lead 1,379
66-34 Lead-Tin Solder 1,318
I think that the K values in MIL-M-38510J are considerably higher
because the bond wires are relatively short. Thus we can have
significant heat conduction to the bonding pads, which cools off the
wires and lets us run more current through them safely.
John Barnes KS4GL, PE, NCE, ESDC Eng., SM IEEE
dBi Corporation
http://www.dbicorporation.com/
------------------------------------------------------------------
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 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:
