SRDA3.3-4 RailClamp® Low Capacitance TVS Array PROTECTION PRODUCTS - RailClamp® Description Features 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 transmission 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 capacitance 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 reductions in leakage current and capacitance over siliconavalanche 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 measures 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. Transient protection for high-speed data lines to 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 Circuit Diagram T1/E1 secondary IC Side Protection T3/E3 secondary IC Side Protection Analog Video Protection Microcontroller Input Protection Base stations I2C Bus Protection Schematic and PIN Configuration 2, 3 I/O 1 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 I/O 2 I/O 3 I/O 4 I/O 1 1 8 GND NC 2 7 I/O 4 NC 3 6 I/O 3 I/O 2 4 5 GND 5, 8 S0-8 (Top View) Revision 01/15/08 1 www.semtech.com SRDA3.3-4 PROTECTION PRODUCTS Absolute Maximum Rating R ating Symbol Value Units Peak Pulse Power (tp = 8/20μs) Pp k 500 Watts Peak Pulse Current (tp = 8/20μs) IP P 25 A Lead Soldering Temp erature TL 260 (10 sec.) °C Op erating Temp erature TJ -40 to +85 °C TSTG -55 to +150 °C Storage Temp erature Electrical Characteristics (T=25oC) SR DA3.3-4 Parameter Reverse Stand-Off Voltage Symbol Conditions Minimum Typical VRWM Maximum Units 3.3 V Punch-Through Voltage V PT IPT = 2μA 3.5 V Snap -Back Voltage VSB ISB = 50mA 2.8 V Reverse Leakage Current IR VRWM = 3.3V, T=25°C 1 μA Clamp ing Voltage VC IPP = 1A, tp = 8/20μs 5.3 V Clamp ing Voltage VC IPP = 10A, tp = 8/20μs 10 V Clamp ing Voltage VC IPP = 25A, tp = 8/20μs 15 V Junction Cap acitance Cj Between I/O p ins and Ground VR = 0V, f = 1MHz 8 15 pF Between I/O p ins VR = 0V, f = 1MHz 4 © 2008 Semtech Corp. 2 pF www.semtech.com SRDA3.3-4 PROTECTION PRODUCTS Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve 10 110 % of Rated Power or PI P Peak Pulse Power - Ppk (kW) 100 1 0.1 90 80 70 60 50 40 30 20 10 0 0.01 0.1 1 10 100 0 1000 25 50 75 100 125 150 Ambient Temperature - TA (oC) Pulse Duration - tp (µs) Pulse Waveform Clamping Voltage vs. Peak Pulse Current 110 20 Waveform Parameters: tr = 8µs td = 20µs 90 18 Clamping Voltage - Vc (V) 100 Percent of I PP 80 70 e-t 60 50 40 td = I PP/2 30 16 14 12 10 8 Waveform Parameters: tr = 8∠s td = 20∠s 6 20 4 10 2 0 0 0 5 10 15 20 25 0 30 5 10 15 20 25 Peak Pulse Current - Ipp (A) Time (µs) Normalized Junction Capacitance vs. Reverse Voltage 1.04 1.02 Cj (VR) / Cj (VR=0) 1 0.98 0.96 0.94 0.92 0.9 0.88 0 0.5 1 1.5 2 2.5 3 3.5 Reverse Voltage - VR (V) © 2008 Semtech Corp. 3 www.semtech.com SRDA3.3-4 PROTECTION PRODUCTS Applications Information Device Connection Options for Protection of Four High-Speed Data Lines Data Line Protection Using Internal TVS Diode as Reference These devices are designed to protect low voltage data lines operating at 3.3 volts. When the voltage on the protected line exceeds the punch-through or “turn-on” voltage of the TVS diode, 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. Pins 5 and 8 should be connected directly to a ground plane. The path length is kept as short as possible to minimize parasitic inductance. Note that pins 2 and 3 are connected internally to the cathode of the low voltage TVS. It is not recommended that these pins be directly connected to a DC source greater than the snap-back votlage (VSB) as the device can latch on as described below. EPD TVS IV Characteristic Curve EPD TVS Characteristics IPP These devices are constructed using Semtech’s proprietary EPD technology. By utilizing the EPD technology, the SRDA3.3-4 can effectively operate at 3.3V while maintaining excellent electrical characteristics. ISB The EPD TVS employs a complex nppn structure in contrast to the pn structure normally found in traditional silicon-avalanche TVS diodes. Since the EPD TVS devices use a 4-layer structure, they exhibit a slightly different IV characteristic curve when compared to conventional devices. During normal operation, the device represents a high-impedance to the circuit up to the device working voltage (VRWM). During an ESD event, the device will begin to conduct and will enter a low impedance state when the punch through voltage (VPT) is exceeded. Unlike a conventional device, the low voltage TVS will exhibit a slight negative resistance characteristic as it conducts current. This characteristic aids in lowering the clamping voltage of the device, but must be considered in applications where DC voltages are present. IPT VBRR VRWM VSB VPT VC IBRR current (ISB). To return to a non-conducting state, the current through the device must fall below the ISB (approximately <50mA) and the voltage must fall below the VSB (normally 2.8 volts for a 3.3V device). If a 3.3V TVS is connected to 3.3V DC source, it will never fall below the snap-back voltage of 2.8V and will therefore stay in a conducting state. When the TVS is conducting current, it will exhibit a slight “snap-back” or negative resistance characteristics due to its structure. This point is defined on the curve by the snap-back voltage (VSB) and snap-back © 2008 Semtech Corp. IR 4 www.semtech.com SRDA3.3-4 PROTECTION PRODUCTS Typical Applications LC01-6 8 5 1 4 SRDA3.3-4 LC01-6 T1/E1 Interface Protection (GR-1089 Long Haul) © 2008 Semtech Corp. 5 www.semtech.com SRDA3.3-4 PROTECTION PRODUCTS Applications Information - Spice Model Pin 2 & 3 Pin 1, 4, 6, or 7 0.6 nH Pin 5 & 8 SRDA3.3-4 Spice Model SRDA3.3-4 Spice Parameters © 2008 Semtech Corp. Parameter Unit D1 (LCRD) D2 (LCRD) D3 (T VS) IS Amp 2.092E-11 2.156E-12 6.09E-14 BV Volt 680 240 3.54 VJ Volt 0.62 0.64 13.8 RS O hm 0.180 0.155 0 .2 2 0 IBV Amp 1 E -3 1E-3 10E-3 CJO Farad 5.2E-12 6.2E-12 45E-12 TT sec 2.541E-9 2.541E-9 2.541E-9 M -- 0.058 0.058 0.111 N -- 1.1 1.1 1.1 EG eV 1.11 1.11 1.11 6 www.semtech.com SRDA3.3-4 PROTECTION PRODUCTS Outline Drawing - SO-8 A h D e N h DIM H 2X E/2 E1 E 1 2 0.25 ccc C 2X N/2 TIPS A A1 A2 b c D E1 E e h L L1 N 01 aaa bbb ccc c GAGE PLANE L (L1) e/2 DETAIL B 01 A D aaa C A2 A SEATING PLANE 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 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. © 2008 Semtech Corp. 7 www.semtech.com SRDA3.3-4 PROTECTION PRODUCTS Ordering Information Marking Diagram SC YYWW SRDA3.3-4 PHIL Part Number Lead Finish Qty per Reel R eel Size SRDA3.3-4.TB SnPb 500 7 Inch SRDA3.3-4.TBT Matte Sn 500 7 Inch Note: Lead-free devices are RoHS/WEEE Compliant Note: YYWW = Date Code Tape and Reel Specification Pin 1 Location User Direction of feed Device Orientation in Tape A0 6.50 +/-0.20 mm B0 K0 5.40 +/-0.20 mm 2.00 +/-0.10 mm Tape Width B, (Max) D D1 E F K (MAX) P P0 P2 T(MAX) W 12 mm 8.2 mm 1.5 + 0.1 mm - 0.0 mm 1.5 mm 1.750±.10 mm 5.5±0.05 mm 4.5 mm 4.0±0.1 mm 4.0±0.1 mm 2.0±0.05 mm 0.4 mm 12.0 mm ±0.3 Contact Information Semtech Corporation Protection Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 © 2008 Semtech Corp. 8 www.semtech.com