SRDA70-4 RailClamp Low Capacitance TVS Diode Array PROTECTION PRODUCTS Description Features RailClamps are surge rated diode arrays designed to protect high speed data interfaces. The SRDA70-4 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 unique design of the SRDA70-4 integrates eight surge rated, low capacitance steering diodes in a low profile SO-8 package. During transient conditions, the steering diodes direct the transient to either the positive side of the power supply line or to ground. The SRDA70-4 may be used as a stand alone device or in conjunction with TVS diodes for enhanced protection. The low capacitance array configuration allows the user to protect four high speed data or I/O lines. The low inductance construction minimizes voltage overshoot during high current surges. 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 diodes Protects four I/O lines Low capacitance for high-speed interfaces High surge capability Low forward voltage characteristics Solid-state silicon avalanche technology Mechanical Characteristics JEDEC SO-8 package UL 497B listed Molding compound flammability rating: UL 94V-0 Marking : Part number, date code, logo Packaging : Tube or Tape and Reel per EIA 481 RoHS/WEEE Compliant Applications Circuit Diagram Schematic and PIN Configuration REF 1 I/O 1 Latch-Up Protection Microcontroller Input Protection Token Ring I2C Bus Protection Video Line Protection Set Top Box I/O LAN/WAN Equipment I/O 2 I/O 3 I/O 4 REF 2 I/O 1 1 8 REF 2 REF 1 2 7 I/O 4 REF 1 3 6 I/O 3 I/O 2 4 5 REF 2 SO-8 (Top View) Revision 08/15/06 1 www.semtech.com SRDA70-4 PROTECTION PRODUCTS Absolute Maximum Rating R ating Symbol Value Units IP P 24 A Rectifier Repetitive Peak Reverse Voltage V RRM 70 V Thermal Resistance, Junction to Ambient θJ A 163 °C /W Thermal Resistance, Junction to Case θJ C 38.8 °C /W Lead Soldering Temperature TL 260 (10 sec.) °C Operating Temperature TJ -55 to +125 °C TSTG -55 to +150 °C Peak Pulse Current (tp = 8/20µs) Storage Temperature Electrical Characteristics SR DA70-4 Parameter Symbol Conditions Rectifier Rep etitive Peak reverse Voltage V RRM Reverse Breakdown Voltage V BR It = 50µA Reverse Leakage Current IR VRWM = 70V, T=25°C 5 µA Forward Voltage VF IPP = 1A, tp = 8/20µs 1.3 V Forward Voltage VF IPP = 10A, tp = 8/20µs 3.3 V Junction Cap acitance Cj Between I/O p ins and Ground VR = 0V, f = 1MHz 15 pF Between I/O p ins VR = 0V, f = 1MHz 2006 Semtech Corp. 2 Minimum Typical Maximum Units 70 V 85 V 4 pF www.semtech.com SRDA70-4 PROTECTION PRODUCTS Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve 10 110 90 % of Rated Power or PI P Peak Pulse Power - Ppk (kW) 100 1 0.1 80 70 60 50 40 30 20 10 0 0.01 0.1 1 10 100 0 1000 25 Pulse Waveform 80 Percent of IPP 125 150 -2 % Change in Capacitance 90 -t 60 50 40 100 0 W aveform Parameters: tr = 8µs td = 20µs 100 e 75 Variation of Capacitance vs. Reverse Voltage 110 70 50 Ambient Temperature - TA (oC) Pulse Duration - tp (µs) td = I PP /2 30 20 -4 -6 -8 -10 -12 -14 10 -16 0 0 5 10 15 20 25 0 30 1 2 3 4 5 6 Reverse Voltage - VR (V) T im e (µs) Foward Voltage vs. Forward Current 10 Forward Voltage - VF (V) 9 8 7 6 5 4 3 Waveform Parameters: tr = 8µs td = 20µs 2 1 0 0 5 10 15 20 25 30 35 40 45 50 Forward Current - IF (A) 2006 Semtech Corp. 3 www.semtech.com SRDA70-4 PROTECTION PRODUCTS Applications Information I/O Protection Device Connection Options for Protection of Four High-Speed Data Lines The SRDA70-4 TVS is designed to protect four 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 VF) the steering diodes are forward biased, conducting the transient current away from the sensitive circuitry. Data lines are connected at pins 1, 4, 6 and 7. The negative reference (REF2) is connected at pins 5 and 8. These pins 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 (REF1) is connected at pins 2 and 3. The options for connecting the positive reference are as follows: Microcontroller Protection 1. To protect data lines and the power line, connect pins 2 and 3 directly to the positive supply rail (VCC). 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. The SRDA70-4 can be isolated from the power supply by adding a series resistor between pins 2 and 3 and VCC. A value of 10kΩ is recommended. The internal steering diodes remain biased, providing the advantage of lower capacitance. 3. In applications where no positive supply reference is available, or complete supply isolation is desired, an external TVS diode may be used as the reference. 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). 2006 Semtech Corp. SRDA70-4 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 compared 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. 4 www.semtech.com SRDA70-4 PROTECTION PRODUCTS Applications Information - Spice Model Vcc I/O 0.8 nH SRDA70-4 Spice Model SRDA70-4 Spice Parameters 2006 Semtech Corp. Parameter Unit D1 (LCRD) D2 (LCRD) IS Amp 3.54E-14 1.46E-14 BV Volt 680 240 VJ Volt 0.62 0.64 RS O hm 0.330 0.124 IBV Amp 1 E -3 1E-3 CJO Farad 5.2E-12 6.2E-12 TT sec 2.56E-9 2.56E-9 M -- 0.058 0.058 N -- 1.1 1.1 EG eV 1.11 1.11 5 www.semtech.com SRDA70-4 PROTECTION PRODUCTS Outline Drawing - SO-8 A h D e N h H 2X E/2 E1 E 1 0.25 L (L1) e/2 DETAIL B 01 A D aaa C SEATING PLANE A2 A C SEE DETAIL A .053 .069 .010 .004 .065 .049 .012 .020 .010 .007 .189 .193 .197 .150 .154 .157 .236 BSC .050 BSC .010 .020 .016 .028 .041 (.041) 8 8° 0° .004 .010 .008 1.35 1.75 0.10 0.25 1.25 1.65 0.31 0.51 0.17 0.25 4.80 4.90 5.00 3.80 3.90 4.00 6.00 BSC 1.27 BSC 0.25 0.50 0.40 0.72 1.04 (1.04) 8 0° 8° 0.10 0.25 0.20 SIDE VIEW A1 bxN bbb DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX A A1 A2 b c D E1 E e h L L1 N 01 aaa bbb ccc c GAGE PLANE 2 ccc C 2X N/2 TIPS DIM C A-B D NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 4. REFERENCE JEDEC STD MS-012, VARIATION AA. Land Pattern - SO-8 X DIM (C) G C G P X Y Z Z Y DIMENSIONS INCHES MILLIMETERS (.205) .118 .050 .024 .087 .291 (5.20) 3.00 1.27 0.60 2.20 7.40 P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 2. REFERENCE IPC-SM-782A, RLP NO. 300A. 2006 Semtech Corp. 6 www.semtech.com SRDA70-4 PROTECTION PRODUCTS Ordering Information Part Number Lead Finish Qty per Reel Reel Size SRDA70-4.TB SnPb 500 7 Inch SRDA70-4.TBT Pb Free 500 7 Inch SRDA70-4 SnPb 95/Tube N/A SRDA70-4.T Pb Free 95/Tube N/A Note: Lead-free devices are RoHS/WEEE Compliant Contact Information Semtech Corporation Protection Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 2006 Semtech Corp. 7 www.semtech.com