April 2009 Doc ID 4508 Rev 5 1/9
9
BUX87
High voltage NPN power transistor
Features
■High voltage capability (450 V VCEO)
■Minimum lot-to-lot spread for reliable operation
■High DC current gain
Applications
■Flyback and forward single transistor low
power converters
Description
The BUX87 is manufactured using high voltage
multi-epitaxial planar technology for high
switching speeds and high voltage withstand
capability.
Figure 1. Internal schematic diagram
SOT-32
321
Table 1. Device summary
Order code Marking Package Packaging
BUX87 BUX87 SOT-32 Tube
www.st.com
Electrical ratings BUX87
2/9 Doc ID 4508 Rev 5
1 Electrical ratings
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
VCES Collector-emitter voltage (VBE = 0) 1000 V
VCEO Collector-emitter voltage (IB = 0) 450 V
VEBO Emitter-base voltage (IC = 0) 5 V
ICCollector current 0.5 A
ICM Collector peak current (tp ≤ 5ms) 1 A
IBBase current 0.3 A
IBM Base peak current (tp ≤ 5ms) 0.6 A
PTOT Total power dissipation at Tc = 25 °C 40 W
Tstg Storage temperature -65 to 150 °C
TJMax. operating junction temperature 150
Table 3. Thermal data
Symbol Parameter Value Unit
Rthj-case Thermal resistance junction-case max. 3.1 °C/W
BUX87 Electrical characteristics
Doc ID 4508 Rev 5 3/9
2 Electrical characteristics
Tcase = 25 °C; unless otherwise specified.
Table 4. Electrical characteristics
Symbol Parameter Test conditions Min. Typ. Max. Unit
ICES
Collector cut-off current
(VBE = 0)
VCE = 1000 V
VCE = 1000 V TC = 125 °C
100
1
µA
mA
IEBO
Emitter cut-off current
(IC = 0) VEB = 5 V 1 mA
VCEO(sus)(1)
1. Pulsed duration = 300 µs, duty cycle ≤ 1.5%
Collector-emitter
sustaining voltage (IB = 0) IC = 10 mA 450 V
VEBO
Emitter-base voltage
(IC = 0) IE = 10 mA 5 V
VCE(sat)(1) Collector-emitter
saturation voltage
IC = 0.1 A IB = 10 mA
IC = 0.2 A IB = 20 mA
0.8
1
V
V
VBE(sat)(1) Base-emitter saturation
voltage IC = 0.2 A IB = 20 mA 1 V
hFE(1) DC current gain IC = 50 mA VCE = 5 V
IC = 40 mA VCE = 5 V 12
50
fTTransition frequency IC = 50 mA VCE = 10 V
f = 1MHz 20 MHz
ts
tf
Resistive load
Storage time
Fall time
VCC = 250 V IC = 200 mA
IB(on) = 40 mA IB(off) = -80 mA
tP = 20 µs
4.5
0.5
µs
µs
Electrical characteristics BUX87
4/9 Doc ID 4508 Rev 5
2.1 Electrical characteristics (curves)
Figure 2. Safe operating area Figure 3. Derating curve
Figure 4. DC current gain Figure 5. DC current gain
Figure 6. Collector-emitter saturation voltage Figure 7. Base-emitter saturation voltage
BUX87 Electrical characteristics
Doc ID 4508 Rev 5 5/9
Figure 8. Reverse biased SOA
Package mechanical data BUX87
6/9 Doc ID 4508 Rev 5
3 Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
BUX87 Package mechanical data
Doc ID 4508 Rev 5 7/9
DIM. mm.
MIN. TYP MAX.
A2.4 2.9
B 0.64 0.88
B1 0.39 0.63
D 10.5 11.05
E7.4 7.8
e 2.04 2.29 2.54
e1 4.07 4.58 5.08
L15.3 16
P2.9 3.2
Q3.8
Q1 1 1.52
H2 2.15
I1.27
SOT-32 (TO-126) MECHANICAL DATA
0016114E
BUX87
Doc ID 4508 Rev 5 9/9
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