The key factors in these equations are: R
S
, the series resis-
tance of the diode where heat is generated under high
current conditions;
θ
chip
, the chip thermal resistance of
the Schottky die; and
θ
package
, or the package thermal
r
esistance.
R
S
for the HBAT-540x family of diodes is typically .4Ω,
other than the HSMS-70x family, this is the lowest of
any Schottky diode available. Chip thermal resistance is
typically 40°C/W; the thermal resistance of the iron-alloy-
leadframe, SOT-3 package is typically 460°C/W; and the
thermal resistance of the copper-leadframe, SOT-33
package is typically 110°C/W. The impact of package
thermal resistance on the current handling capability
of these diodes can be seen in Figures 3 and 4. Here the
computed values of junction temperature vs. forward
current are shown for three values of ambient tempera-
ture. The SOT-33 products, with their copper leadframes,
can safely handle almost twice the current of the larger
SOT-3 diodes. Note that the term “ambient temperature”
refers to the temperature of the diode’s leads, not the air
around the circuit board. It can be seen that the HBAT-
540B and HBAT-540C products in the SOT-33 package
will safely withstand a steady-state forward current of 330
mA when the diode’s terminals are maintained at 75°C.
For pulsed currents and transient current spikes of less
than one microsecond in duration, the junction does
not have time to reach thermal steady state. Moreover,
the diode junction may be taken to temperatures higher
than 150°C for short timeperiods without impacting
device MTTF. Because of these factors, higher currents
can be safely handled. The HBAT-540x family has the
second highest current handling capability of any Avago
diode, next to the HSMS-70x series.
Part Number Ordering Information
Part Number
HBAT-5400-BLKG
HBAT-5400-TR1G
HBAT-5400-TRG
HBAT-540-BLKG
HBAT-540-TR1G
HBAT-540-TRG
HBAT-540B-BLKG
HBAT-540B-TR1G
HBAT-540B-TRG
HBAT-540C-BLKG
HBAT-540C-TR1G
HBAT-540C-TRG
No. of Devices
100
3,000
10,000
100
3,000
10,000
100
3,000
10,000
100
3,000
10,000
Container
Antistatic Bag
7" Reel
13" Reel
Antistatic Bag
7" Reel
13" Reel
Antistatic Bag
7" Reel
13" Reel
Antistatic Bag
7" Reel
13" Reel
For product information and a complete list of distributors, please go to our web site:
www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies in the United States and other countries.
Data subject to change. Copyright © 2005-2008 Avago Technologies. All rights reserved. Obsoletes 5989-4779EN
AV02-1394EN - July 4, 2008
AVAGO [ AVAGO TECHNOLOGIES LIMITED ]
