PROTECTION PRODUCTS - RailClamp
®
Description
RailClamps are surge rated diode arrays designed to
protect high speed data interfaces. The SRDA series
has been specifically designed to protect sensitive
components which are connected to data and trans-
mission lines from overvoltage caused by electrostatic
discharge
(ESD),
electrical fast transients
(EFT),
and
lightning.
The unique design incorporates surge rated, low
capacitance steering diodes and a TVS diode in a
single package. During transient conditions, the
steering diodes direct the transient current to ground
via the internal low voltage TVS. The TVS diode clamps
the transient voltage to a safe level. The low capaci-
tance array configuration allows the user to protect up
to four high-speed data lines.
The SRDA3.3-4 is constructed using Semtech’s
proprietary EPD process technology. The EPD process
provides low stand-off voltages with significant reduc-
tions in leakage current and capacitance over silicon-
avalanche diode processes. They feature a true
operating voltage of 3.3 volts for superior protection.
These devices are in a 8-pin SOIC package. It mea-
sures 3.9 x 4.9mm. They are available with a SnPb or
RoHS/WEEE compliant matte tin lead finish. The high
surge capability (Ipp=25A, tp=8/20μs) means it can be
used in high threat environments in applications such
as CO/CPE equipment, telecommunication lines, and
video lines.
RailClamp
®
Low Capacitance TVS Array
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) 24A (8/20μs)
Array of surge rated diodes with internal TVS diode
Protects four I/O lines
Low capacitance (<15pF) for high-speed interfaces
Low operating voltage:
3.3V
Low clamping voltage
Solid-state technology
SRDA3.3-4
Mechanical Characteristics
JEDEC SOIC-8 package
Lead Finish: SnPb or Matte Sn
Molding compound flammability rating: UL 94V-0
Marking : Part number, date code, logo
Packaging : Tape and Reel per EIA 481
Applications
T1/E1 secondary IC Side Protection
T3/E3 secondary IC Side Protection
Analog Video Protection
Microcontroller Input Protection
Base stations
I
2
C Bus Protection
Circuit Diagram
Schematic and PIN Configuration
2, 3
I/O 1
1
8
GND
I/O 1
I/O 2
I/O 3
I/O 4
NC
2
7
I/O 4
NC
5, 8
3
6
I/O 3
I/O 2
4
5
GND
S0-8 (Top View)
Revision 01/15/08
www.semtech.com
1
SEMTECH [ SEMTECH CORPORATION ]
