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PROTECTION PRODUCTS
SDC36
TVS Diode Array for
Proximity Switch Input Protection
Description
Features
Circuit Diagram
Schematic & PIN Configuration
Revision 9/2000
The SDC36 is a high-surge transient voltage suppres-
sor (TVS) optimized for protection of sensitive digital
sensors used in proximity switches and industrial
control applications. The SDC36 protects the compo-
nents from over-voltages caused by electrostatic
discharge (ESD), electrical fast transients (EFT), and
tertiary lightning.
The unique design of the SDC36 incorporates two TVS
diodes in a compact SOT23 package for applications
where board space is at a premium. The single pack-
age provides protection for the I/O line and power
supply rail with high surge capabilities (2 Amps at
tp=1.2/50us) and an exceptionally low clamping
voltage of <45V.
The SDC36 replaces up to two large discrete diodes
providing the designer an easy to implement integrated
solution. The features of the SDC36 are ideal for
protection of two, three, and four wire DC high-side
proximity switches.
Applications
Mechanical Characteristics
u
Two, Three, and Four Wire DC High-Side Proximity
Switches
u
Digital Sensor Input Protection
u
Industrial Controls
u
24V - 33V DC Supply Protection
u
350 watts peak pulse power (tp = 8/20s)
u
Transient protection for data & power lines to
IEC 61000-4-2 (ESD) 15kV (air), 8kV (contact)
IEC 61000-4-4 (EFT) 40A (5/50ns)
IEC 61000-4-5 (Lightning) 2A (1.2/50s)
u
Replaces two discrete devices
u
Low clamping voltage
u
Low leakage current
u
High surge capability
u
Solid-state silicon avalanche technology
u
JEDEC SOT23 package
u
Molding compound flammability rating: UL 94V-0
u
Marking : DC36
u
Packaging : Tape and Reel per EIA 481
SOT23 (Top View)
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2000 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
SDC36
Absolute Maximum Rating
Electrical Characteristics
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2000 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
PROTECTION PRODUCTS
SDC36
Typical Characteristics
Non-Repetitive Peak Pulse Power vs. Pulse Time
0
10
20
30
40
50
60
70
80
90
100
110
0
25
50
75
100
125
150
Ambient Temperature - T
A
(
o
C)
%
of Rated Power or I
PP
Power Derating Curve
Pulse Waveform
Clamping Voltage vs. Peak Pulse Current
0
10
20
30
40
50
60
70
80
90
100
110
0
5
10
15
20
25
30
Time (
s)
Percent of I
PP
e
-t
td = I
PP
/2
Waveform
Parameters:
tr = 8
s
td = 20
s
Forward Voltage vs. Forward Current
25
30
35
40
45
50
55
60
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
Peak Pulse Current - I
PP
(A)
Clamping Voltage - V
C
(V)
Waveform
Parameters:
tr = 8
s
td = 20
s
Unidirectional
(pin 3 to 1 & 3 to 2)
Bidirectional
(Pin 1 to 2)
0
0.5
1
1.5
2
2.5
3
0
1
2
3
4
5
6
7
8
9
10
11
12
Forward Current - I
F
(A)
Forward Voltage - V
F
(V)
Waveform
Parameters:
tr = 8
s
td = 20
s
0.01
0.1
1
10
0.1
1
10
100
1000
Pulse Duration - tp (
s)
P
eak P
u
l
se P
o
wer - P
PP
(kW)
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2000 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
SDC36
Device Connection for Protection of Two, Three, and
Four Wire Proximity Switches
Digital sensors help to bridge the gap between the
physical world and the digital world in applications such
as computer controlled factory automation. In such
environments, transient voltages can easily disrupt or
damage sensitive sensor inputs. The SDC36 provides
transient voltage protection for the digital sensors to
ensure their operation is not disrupted by the physical
world.
The SDC36 is designed to meet the high surge capabil-
ity and low clamping voltage needed to protect the
ASIC and control logic used in proximity switches. The
SDC36 provides protection for the power and I/O lines.
Typical configurations for the protection of two, three,
and four wire switches are as follows:
1. Two-Wire Switch: Connect pin 1 to the I/O line and
pin 2 to the DC supply (since the device is symmetrical,
these connections can be reversed). Pin 3 is not
connected.
2. Three-Wire Switch: Either pin 1 or pin 2 is con-
nected to the I/O line with the other connected to
ground. Pin 3 must be connected to the DC supply.
3. Four-Wire Switch: Two device are required to
protect four wire switches. Pin 3 of each device is
connected to the DC supply line. Pins 1 & 2 are
connected to the I/O lines & ground as shown.
2-Wire DC Proximity Switch Application
3-Wire DC Proximity Switch Application
4-Wire DC Proximity Switch Application
Applications Information
5
2000 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
PROTECTION PRODUCTS
SDC36
Note 1 : Grid placement courtyard is 8 x 8 elements (4mm x 4mm) in accordance with the international grid detailed in IEC
Publication 97.
Outline Drawing - SOT23
Land Pattern - SOT23
6
2000 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
SDC36
Contact Information
Semtech Corporation
Protection Products Division
652 Mitchell Rd., Newbury Park, CA 91320
Phone: (805)498-2111 FAX (805)498-3804
Ordering Information
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