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HIGH VOLTAGE FAST-SWITCHING NPN POWER DARLINGTON
[
BU808DFI
HIGH VOLTAGE FAST-SWITCHING
NPN POWER DARLINGTON
n
STMicroelectronics PREFERRED
SALESTYPE
NPN MONOLITHIC DARLINGTON WITH
INTEGRATED FREE-WHEELING DIODE
n
HIGH VOLTAGE CAPABILITY ( > 1400 V )
n
HIGH DC CURRENT GAIN ( TYP. 150 )
n
U.L. RECOGNISED ISOWATT218 PACKAGE
(U.L. FILE # E81734 (N))
n
3
n
LOW BASE-DRIVE REQUIREMENTS
2
DEDICATED APPLICATION NOTE AN1184
n
1
APPLICATIONS
n
COST EFFECTIVE SOLUTION FOR
HORIZONTAL DEFLECTION IN LOW END
TV UP TO 21 INCHES.
ISOWATT218
DESCRIPTION
The BU808DFI is a NPN transistor in monolithic
Darlington configuration. It is manufactured using
Multiepitaxial Mesa technology for cost-effective
high performance.
INTERNAL SCHEMATIC DIAGRAM
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V CBO
Collector-Base Voltage (I E = 0)
1400
V
V CEO
Collector-Emitter Voltage (I B = 0)
700
V
V EBO
Emitter-Base Voltage (I C =0)
5
V
I C
Collector Current
8
A
I CM
Collector Peak Current (t p <5ms)
10
A
I B
Base Current
3
A
I BM
Base Peak Current (t p <5ms)
6
A
P tot
Total Dissipation at T c =25 o C
52
W
T stg
Storage Temperature
-65 to 150
o C
T j
Max. Operating Junction Temperature
150
o C
June 2000
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BU808DFI
THERMAL DATA
R thj-case Thermal Resistance Junction-case
Max
2.4
o C/W
ELECTRICAL CHARACTERISTICS (T case =25 o C unless otherwise specified)
Symbol
Parameter
Test Conditions
Min.
Typ. Max.
Unit
I CES
Collector Cut-off
Current (V BE =0)
V CE = 1400 V
400
m
A
I EBO
Emitter Cut-off Current
(I C =0)
V EB =5V
100
mA
V CE(sat)
*
Collector-Emitter
Saturation Voltage
I C =5A
I B =0.5A
1.6
V
V BE(s at)
*
Base-Emitter
Saturation Voltage
I C =5A
I B =0.5A
2.1
V
h FE *
DC Current Gain
I C =5A V CE =5V
I C =5A V CE =5V T j =100 o C
60
20
230
INDUCTIVE LOAD
Storage Time
Fall Time
V CC =150V
I C =5A
t s
t f
I B1 =0.5A
V BEoff =-5V
3
0.8
m s
m
s
INDUCTIVE LOAD
Storage Time
Fall Time
V CC =150V
I C =5A
t s
t f
I B1 =0.5A
V BEoff =-5V
2
0.8
m s
m
T j =100 o C
s
V F
Diode Forward Voltage I F =5A
3
V
*
Pulsed: Pulse duration = 300
m
s, duty cycle 1.5 %
Safe Operating Area
Thermal Impedance
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BU808DFI
Derating Curve
DC Current Gain
Collector Emitter Saturation Voltage
Base Emitter Saturation Voltage
Power Losses at 16 KHz
Switching Time Inductive Load at 16KHz
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BU808DFI
Switching Time Inductive Load at 16KHZ
Reverse Biased SOA
BASE DRIVE INFORMATION
In order to saturate the power switch and reduce
conduction losses, adequate direct base current
I B1 has to be provided for the lowest gain h FE at
100 o C (line scan phase). On the other hand,
negative base current I B2 must be provided to
turn off the power transistor (retrace phase).
Most of the dissipation, in the deflection
application, occurs at switch-off. Therefore it is
essential to determine the value of I B2 which
minimizes power losses, fall time t f and,
consequently, T j . A new set of curves have been
defined to give total power losses, t s and t f as a
function of I B2 at both 16 KHz scanning
frequencies for choosing the optimum negative
drive. The test circuit is illustrated in figure 1.
Inductance L 1 serves to control the slope of the
negative base current I B2 to recombine the
excess carrier in the collector when base current
is still present, this would avoid any tailing
phenomenon in the collector current.
The values of L and C are calculated from the
following equations:
1
2
2
=
1
2
C ( V CEfly )
2
w= 2 p f =
1
````
L C
Where I C = operating collector current, V CEfly =
flyback voltage, f= frequency of oscillation during
retrace.
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L ( I C )
199620756.005.png
BU808DFI
Figure 1: Inductive Load Switching Test Circuits.
Figure 2: Switching Waveforms in a Deflection Circuit
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