Low Capacitance TVS Diode
For High Speed Data Interfaces
PROTECTION PRODUCTS
Description
The SL series of TVS arrays are designed to protect
sensitive electronics from damage or latch-up due to
ESD, lightning, and other voltage-induced transient
events. They are available with operating voltages of
5V, 12V, 15V and 24V.
TVS diodes are solid-state devices designed specifically
for transient suppression. They offer desirable charac-
teristics for board level protection including fast re-
sponse time, low operating and clamping voltage, and
no device degradation. The SL series devices feature
a low capacitance, fast switching compensation diode
in series with a standard TVS diode. This effectively
reduces the overall capacitance of the device to less
than 5pF making it an integrated, low capacitance
solution for use on high-speed interfaces.
The SL series devices may be used to meet the immu-
nity requirements of IEC 61000-4-2, level 4.
SL05 through SL24
Features
Transient protection for high-speed data lines to
IEC 61000-4-2 (ESD) ±15kV (air), ±8kV (contact)
IEC 61000-4-4 (EFT) 40A (5/50ns)
IEC 61000-4-5 (Lightning) 12A (8/20µs)
Small package for use in portable electronics
Two devices will protect one line
Low capacitance for high-speed data lines
Working voltages: 5V, 12V, 15V and 24V
Solid-state silicon avalanche technology
Mechanical Characteristics
JEDEC SOT23 package
Molding compound flammability rating: UL 94V-0
Marking : Marking Code
Packaging : Tape and Reel per EIA 481
Applications
High-Speed data lines
Cellular handsets AND accessories
Universal Serial Bus (USB) port protection
Portable instrumentation
LAN/WAN equipment
Peripherals
Circuit Diagram
Schematic & PIN Configuration
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3
(N.C.)
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SOT23 Top View
Revision 09/23/04
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SL05 through SL24
PROTECTION PRODUCTS
Applications Information
Device Connection for Protection of One High-Speed
Data Line
The SL series devices are designed to protect high-
speed data lines. The SLxx utilizes a low capacitance
compensation diode in series with, but in opposite
polarity to a TVS diode in each line to achieve an
effective capacitance of less than 5pF per device.
During a transient event, the internal rectifier must be
forward biased (TVS is reversed biased). Therefore,
each device will only suppress transient events in one
polarity. To achieve protection in both positive and
negative polarity, a second device is connected in anti-
parallel to the first. On unidirectional lines, a fast
switching steering diode may be used as an alternative
to using two SL devices.
The options for connecting the devices are as follows:
Low capacitance protection of one high-speed
line:
Protection of one unidirectional or bidirec-
tional high-speed line is achieved by connecting two
devices in anti-parallel. Pin 1 of the first device is
connected to the line and pin 2 is connected to
ground (or to a second line for differential protec-
tion). Pin 2 of the second device is connected to
line 1 and pin 1 is connected to ground (or line 2)
as shown. Pin 3 is not connected. During positive
duration transients, the first device will conduct
from pin 1 to 2. The steering diode conducts in the
forward direction while the TVS will avalanche and
conduct in the reverse direction. During negative
transients, the second device will conduct in the
same manner. For optimum protection, the ground
connections should be made directly to the ground
plane for best results. The path length is kept as
short as possible to reduce the effects of parasitic
inductance in the board traces. The path length
between the TVS and the protected line should
also be minimized.
Connection Option for Unidirectional Lines Only:
An optional method for protecting unidirectional
(normal signal polarities above ground) lines is to
add a fast switching steering diode in parallel to the
SL TVS. Input/outputs are connected to pin 1 of
the SL device and the cathode of the rectifier. The
anode of the diode and pin 2 of the SL TVS are
connected to ground.
SL Connection Options
Two Devices : Bidirectional or Unidirectional Line
One Devices with Steering Diode : Unidirectional Line
I/O Line Protection
Matte Tin Lead Finish
Matte tin has become the industry standard lead-free
replacement for SnPb lead finishes. A matte tin finish
is composed of 100% tin solder with large grains.
Since the solder volume on the leads is small com-
pared to the solder paste volume that is placed on the
land pattern of the PCB, the reflow profile will be
determined by the requirements of the solder paste.
Therefore, these devices are compatible with both
lead-free and SnPb assembly techniques. In addition,
unlike other lead-free compositions, matte tin does not
have any added alloys that can cause degradation of
the solder joint.
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