SR70 SEMTECH | Alldatasheet
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Technical content
1 www.semtech.com PROTECTION PRODUCTS SR70 Low Capacitance TVS Diode Array Description Features Circuit Diagram Schematic & PIN Configuration Revision 04/18/03 RailClamps are surge rated diode arrays designed to protect high speed data interfaces. The SR70 has been specifically designed to protect sensitive compo- nents which are connected to data and transmission lines from over-voltages caused by ESD (electrostatic discharge), EFT (electrical fast transients), and light- ning. 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 de- signed 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 (V F) above the supply (reference) voltage. The SR70 may be used as a stand alone device or in conjunction with TVS diodes for enhanced protection.
Applications
Mechanical Characteristics 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 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 JEDEC SOT-143 package UL 497B listed Molding compound flammability rating: UL 94V-0 Marking : R70 Packaging : Tape and Reel per EIA 481 Pin 4 Pin 2 Pin 3 Pin 1 SOT-143 (Top View)
2 2003 Semtech Corp. www.semtech.com PROTECTION PRODUCTS SR70 Absolute Maximum Rating Electrical Characteristics (T=25 oC) 07RS retemaraPl obmySs noitidnoCm uminiMl acipyTm umixaMs tinU egatloVffO-dnatSesreveRkaePV MRR 07V egatloVnwodkaerBesreveRV RB It 05= µA5 8V tnerruCegakaeLesreveRI R V MWR C°52=T,V07=5 A µ egatloVgnipmalCdrawroFV CF I PP t,A1= p sµ02/8=5 .1V egatloVgnipmalCdrawroFV CF I PP t,A01= p sµ02/8=3 .3V egatloVgnipmalCdrawroFV CF I PP t,A42= p sµ02/8=7 V ecnaticapaCnoitcnuJC j dnasnipO/IneewteB dnuorG VR zHM1=f,V0= 50 1F p snipO/IneewteB VR zHM1=f,V0= 3F p gnitaRl obmySe ulaVs tinU t(tnerruCesluPkaeP p )sµ02/8=I PP 42A egatloVesreveRkaePevititepeRreifitceRV MRR 07V )riA(2-4-00016CEIrepDSE )tcatnoC(2-4-00016CEIrepDSE V DSE 51 Vk erutarepmeTgniredloSdaeLT L ).ces01(062C ° erutarepmeTgnitarepOT J 521+ot55-C ° erutarepmeTegarotST GTS 051+ot55-C °
3 2003 Semtech Corp. www.semtech.com PROTECTION PRODUCTS SR70 Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve 100 110 0 25 50 75 100 125 150 Ambient Temperature - T A (oC) % of Rated Power or IPP 100 110 0 5 10 15 20 25 30 Time (µs) Percent of IPP e-t td = IPP/2 Waveform Parameters: tr = 8µs td = 20µs Pulse Waveform Forward Voltage vs. Forward Current Capacitance vs. Reverse Voltage 0 5 10 15 20 25 30 35 40 45 50 Forward Current - I F (A) Forward Voltage - VF (V) Waveform Parameters: tr = 8µs td = 20µs -16 -14 -12 -10 0123456 Reverse Voltage - VR (V) % Change in Capacitance I/O to GND f = 1MHz 0.01 0.1 0.1 1 10 100 1000 Pulse Duration - tp (µs) Peak Pulse Power - PPk (kW)
4 2003 Semtech Corp. www.semtech.com PROTECTION PRODUCTS SR70 Device Connection Options for Protection of Two High-Speed Data Lines The SR70 is designed to protect two data lines from transient over-voltages by clamping them to a fixed reference. When the voltage on the protected line exceeds the reference voltage (plus diode V F) the steering diodes are forward biased, conducting the transient current away from the sensitive circuitry. Data lines are connected at pins 2 and 3. The nega- tive reference (REF1) is connected at pin 1. This pin should be connected directly to a ground plane on the board for best results. The path length is kept as short as possible to minimize parasitic inductance. The positive reference (REF2) is connected at pin 4. The options for connecting the positive reference are as follows: 1. To protect data lines and the power line, connect pins 2 and 3 directly to the positive supply rail (V CC). In this configuration the data lines are referenced to the supply voltage. An external TVS diode may be added between the supply rail and ground in order to prevent over-voltage on the supply rail. 2. In applications where no positive supply reference is available, or complete supply isolation is desired, an external TVS diode may be used as the refer- ence. The steering diodes will begin to conduct when the voltage on the protected line exceeds the working voltage of the TVS (plus one diode drop). SR70 Pin Configuration Applications Information Data Line and Power Supply Protection Using Vcc as reference
5 2003 Semtech Corp. www.semtech.com PROTECTION PRODUCTS SR70 Land Pattern Notes: (1) Controlling dimension: Inch (unless otherwise specified). (2) Dimension A and B do not include mold protrusions. Mold protrusions are .006” max. Outline Drawing
6 2003 Semtech Corp. www.semtech.com PROTECTION PRODUCTS SR70 Contact Information Semtech Corporation Protection Products Division 200 Flynn Rd., Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 traP rebmuN repytQ leeR eziSleeR CT.07RS0 00,3h cnI7 GT.07RS0 00,01h cnI31 Marking Codes rebmuNtraP gnikraM edoC 07RS0 7R
Ordering Information
SR70 Marking (Top View)