Description
RailClamps are surge rated diode arrays designed to protect high speed data interfaces. The SR70 has been specifically designed to protect sensitive components which are connected to data and transmission lines from over-voltages caused by electrostatic discharge (ESD), electrical fast transients (EFT), and lightning. The SR70 has been optimized for use on ADSL and other high-speed interfaces.
The unique design of the SR70 integrates four surge rated, low capacitance steering diodes in a low profile SOT-143 package. It has a typical capacitance of only 5pF and may be used to protect two high-speed lines without sacrificing signal integrity. The SR70 is designed to replace “standard” rectifiers that are not rated for the high energy surges that are normally expected in telecommunications applications.
During transient conditions, the steering diodes direct the transient to either the positive side of the power supply line or to ground. The maximum clamping voltage seen by the protected circuit will be one diode drop (VF) above the supply (reference) voltage. The SR70 may be used as a stand alone device or in conjunction with TVS diodes for enhanced protection.

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) 1kV, 24A (8/20μs)
Array of surge rated, low capacitance diodes
Protects two I/O lines
Low capacitance (5pF typical) for high-speed interfaces
Low clamping voltage
Solid-state silicon-avalanche technology

Applications
ADSL Lines
I2C Bus Protection
Video Line Protection
T1/E1 secondary IC Side Protection
Portable Electronics
Microcontroller Input Protection
WAN/LAN Equipment
ISDN S/T Interface