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DB3 DB4 SMDB3
®
October 2001 - Ed: 2B
DIAC
DO-35
(DB3 and DB4)
■VBO : 32V and 40V
■LOW BREAKOVER CURRENT
FEATURES
Functioning as a trigger diode with a fixed voltage
reference, the DB3/DB4 series can be used in
conjunction with triacs for simplified gate control
circuits or as a starting element in fluorenscent
lamp ballasts.
A new surface mount version is now available in
SOT-23 package, providing reduced space and
compatibility with automatic pick and place
equipment.
DESCRIPTION
Symbol Parameter Value Unit
ITRM Repetitive peak on-state current
tp=20µs F= 120 Hz SMDB3 1.00 A
DB3 / DB4 2.00
Tstg
Tj Storage temperature range
Operating junction temperature range -40to+125 °C
ABSOLUTE MAXIMUM RATINGS (limiting values)
1
23
SOT-23
(SMDB3)*
Pin 1 and 3 must be shorted
together
Note: * SMDB3 indicated as Preliminary spec as product is still in development stage.
DB3 DB4 SMDB3
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Symbol Parameter Test Conditions SMDB3 DB3 DB4 Unit
VBO Breakover voltage * C = 22nF ** MIN. 28 28 35 V
TYP. 32 32 40
MAX. 36 36 45
IV
BO1 -V
BO2 I Breakover voltage
symmetry C = 22nF ** MAX. 3 V
∆V Dynamic breakover
voltage * VBO and VFat 10mA MIN. 10 5 V
VOOutput voltage * see diagram 2
(R=20Ω)MIN. 10 5 V
IBO Breakover current * C = 22nF ** MAX. 10 50 µA
tr Rise time * see diagram 3 MAX. 0.50 2 µs
IRLeakage current * VR= 0.5 VBO max MAX. 1 10 µA
IPPeak current * see diagram 2 (Gate) MIN. 1 0.30 A
* Applicable to both forward and reverse directions.
** Connected in parallel to the device.
ELECTRICAL CHARACTERISTICS (Tj = 25°C unless otherwise specified)
Part Number VBO Package
SMDB3 28 - 36 SOT-23
DB3 28 - 36 DO-35
DB4 35 - 45 DO-35
PRODUCT SELECTOR
SM DB 3
Surface
Mount
Version
Diac Series
Breakover voltage
3:V typ = 32V
4:V typ = 40V
BO
BO
ORDERING INFORMATION
DB3 DB4 SMDB3
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10mA
IBO
IB
-V +V
+I
F
-I
F
0,5 VBO
VBO
V
VF
Diagram 1: Voltage - current characteristic curve.
D.U.T
Vo
C=0.1µF
220V
50 Hz
500 kΩ10 kΩ
R=20 Ω
IP
Rs=0
T410
Diagram 2: Test circuit.
90 % l
p
10 % t
r
Diagram 3: Rise time measurement.
Part Number Marking Weight Base Quantity Packing Mode
SMDB3 DB3 0.01 g 3000 Tape & Reel
DB3 DB3 (Blue Body Coat) 0.15 g 5000 Tape & Reel
DB4 DB4 (Blue Body Coat) 0.15 g 5000 Tape & Reel
OTHER INFORMATION
DB3 DB4 SMDB3
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10 20 50 100 200 500
0
5
10
15
20
25
30
35
40
C(nF)
tp(µs)
Tj=25°C
0Ω
10Ω
22Ω
68Ω
47Ω
33Ω
Fig. 3: Time duration while current pulse is higher
50mA versus C and Rs (typical values).
PACKAGE MECHANICAL DATA (in millimeters)
DO-35
REF. DIMENSIONS
Millimeters Inches
Min. Max. Min. Max.
A 3.05 4.50 0.120 0.177
B 1.53 2.00 0.060 0.079
C 28.00 1.102
D 0.458 0.558 0.018 0.022
CA BO
/
O
/
D
O
/
D
C
25 50 75 100 125
0.80
0.85
0.90
0.95
1.00
1.05
1.10
Tj(°C)
VBO [Tj] /VBO [Tj=25°C]
SMDB3
DB3/DB4
Fig. 1: Relative variation of VBO versus junction
temperature (typical values).
1 10 100
0.1
1.0
10.0
20.0
tp(µs)
ITRM(A)
SMDB3
DB3/DB4
F=120Hz
Tj initial=25°C
Fig. 2: Repetitive peak pulse current versus pulse
duration (maximum values).
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DB3 DB4 SMDB3
Informationfurnished is believedto be accurateand reliable. However,STMicroelectronics assumes noresponsibility for theconsequences of
useof such information nor forany infringementof patents orother rightsof third partieswhich mayresult from its use. Nolicense is granted by
implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to
change without notice. This publication supersedes and replaces all information previously supplied.
STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written ap-
proval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics
© 2001 STMicroelectronics - Printed in Italy - All rights reserved.
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PACKAGE MECHANICAL DATA (in millimeters)
SOT-23
B
E
S
e
e1
A
D
c
L
H
A1
REF. DIMENSIONS
Millimeters Inches
Min. Max. Min. Max.
A 0.89 1.4 0.035 0.055
A1 0 0.1 0 0.004
B 0.3 0.51 0.012 0.02
c 0.085 0.18 0.003 0.007
D 2.75 3.04 0.108 0.12
e 0.85 1.05 0.033 0.041
e1 1.7 2.1 0.067 0.083
E 1.2 1.6 0.047 0.063
H 2.1 2.75 0.083 0.108
L 0.6 typ. 0.024 typ.
S 0.35 0.65 0.014 0.026
0.9
0.035 0.9
0.035
1.9
0.075
mm
inch
2.35
0.92
1.1
0.043
1.1
0.043
1.45
0.037
0.9
0.035
FOOTPRINT
