SLVU2.8 Low Voltage EPD TVS Diode For ESD and Latch-Up Protection PROTECTION PRODUCTS Description Features The SLV series of transient voltage suppressors are designed to protect low voltage, state-of-the-art CMOS semiconductors from transients caused by electrostatic discharge (ESD), cable discharge events (CDE), lightning and other induced voltage surges. 400 Watts peak pulse power (tp = 8/20μs) Transient protection for high speed data lines to The devices are constructed using Semtech’s proprietary EPD process technology. The EPD process provides low standoff voltages with significant reductions in leakage currents and capacitance over siliconavalanche diode processes. The SLVU2.8 features an integrated low capacitance compensation diode that allows the device to be configured to protect one unidirectional line or, when paired with a second SLVU2.8, two high-speed line pairs. The low capacitance design of the SLVU2.8 means signal integrity is preserved in high-speed applications such as 10/100 Ethernet. 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) One device protects one unidirectional line Two devices protect two high-speed line pairs Low capacitance Low leakage current Low operating and clamping voltages Solid-state EPD TVS process technology Mechanical Characteristics The SLVU2.8 is in an SOT23 package and has a low 2.8 volt working voltage. It is specifically designed to protect low voltage components such as Ethernet transceivers, laser diodes, ASICs, and high-speed RAM. The low clamping voltage of the SLVU2.8 minimizes the stress on the protected IC. JEDEC SOT23 package Molding compound flammability rating: UL 94V-0 Marking : U2.8 Packaging : Tape and Reel per EIA 481 Applications The SLV series TVS diodes will exceed the surge requirements of IEC 61000-4-2, Level 4. Circuit Diagram 10/100 Ethernet WAN/LAN Equipment Switching Systems Desktops, Servers, Notebooks & Handhelds Laser Diode Protection Base Stations Schematic & PIN Configuration 3 1 3 2 1 2 SOT23 (Top View) Revision 06/25/2008 1 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Absolute Maximum Rating R ating Symbol Value Units Peak Pulse Power (tp = 8/20μs) Pp k 400 Watts Peak Pulse Current (tp = 8/20μs) IP P 24 A Lead Soldering Temp erature TL 260 (10 seconds) o Op erating Temp erature TJ -55 to +125 o TSTG -55 to +150 o Storage Temp erature C C C Electrical Characteristics SLVU2.8 Parameter Symbo l Conditions VRWM Pin 3 to 1 or Pin 2 to 1 Punch-Through Voltage V PT IPT = 2μA, Pin 3 to 1 3.0 V Snap -Back Voltage VSB ISB = 50mA, Pin 3 to 1 2.8 V Reverse Leakage Current IR VRWM = 2.8V, T=25°C Pin 3 to 1 or Pin 2 to 1 1 μA Clamp ing Voltage VC IPP = 2A, tp = 8/20μs Pi n 3 to 1 3.9 V Clamp ing Voltage VC IPP = 5A, tp = 8/20μs Pi n 3 to 1 7 V Clamp ing Voltage VC IPP = 24A, tp = 8/20μs Pi n 3 to 1 12.5 V Clamp ing Voltage VC IPP = 5A, tp = 8/20μs Pi n 2 to 1 8.5 V Clamp ing Voltage VC IPP = 24A, tp = 8/20μs Pi n 2 to 1 15 V Junction Cap acitance Cj Pin 3 to 1 and 2 (Pin 1 and 2 tied together) VR = 0V, f = 1MHz 70 100 pF Junction Cap acitance Cj Pin 2 to 1 (p in 3 N .C.) VR = 0V, f = 1MHz 5 10 pF Reverse Breakdown Voltage V BR IT= 10μA, Pin 3 to 2 Reverse Leakage Current IR D VRWM = 2.8V, T=25°C Pi n 3 to 2 1 μA Forward Voltage VF IF= 1A, Pin 2 to 3 2 V Reverse Stand-Off Voltage Minimum Typical Maximum Units 2.8 V Steering Diode Characteristics © 2008 Semtech Corp. 2 40 V www.semtech.com SLVU2.8 PROTECTION PRODUCTS Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve 110 10 Peak Pulse Power - Ppk (kW) 100 % of Rated Power or IPP 90 1 0.1 80 70 60 50 40 30 20 10 0 0.01 0.1 1 10 100 0 1000 25 75 100 125 150 o Pulse Waveform Clamping Voltage vs. Peak Pulse Current 110 18 W aveform Parameters: tr = 8µs td = 20µs 90 16 Clamping Voltage - VC (V) 100 80 Percent of IPP 50 Ambient Temperature - TA ( C) Pulse Duration - tp (µs) 70 e -t 60 50 40 td = I PP /2 30 20 14 12 10 Pin 3 to 1 8 6 Waveform Parameters: tr = 8µs td = 20µs 4 2 10 0 0 0 5 10 15 20 25 0 30 5 10 15 20 25 30 35 Peak Pulse Current - IPP (A) T im e (µs) Forward Voltage vs. Forward Current Normalized Capacitance vs. Reverse Voltage 16 2 f = 1MHz 1.8 1.6 12 Pin 3 to Pin 1 and 2 1.4 CJ(VR ) / C J(V R=0) Forward Voltage - VF (V) 14 10 8 6 Waveform Parameters: tr = 8µs td = 20µs 4 2 1.2 1 0.8 0.6 Pin 2 to Pin 1 0.4 0.2 0 0 5 10 15 20 25 30 0 35 0 Forward Current - IF (A) © 2008 Semtech Corp. 0.5 1 1.5 2 2.5 3 Reverse Voltage - VR (V) 3 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Typical Characteristics (Continued) Insertion Loss S21 CH1 S21 LOG START . 030 MHz © 2008 Semtech Corp. 10 dB /REF 0 dB STOP 3000. 000000 MHz 4 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Applications Information Device Connection Options SLVU2.8 Circuit Diagram Electronic equipment is susceptible to transient disturbances from a variety of sources including: ESD to an open connector or interface, direct or nearby lightning strikes to cables and wires, and charged cables “hot plugged” into I/O ports. The SLVU2.8 is designed to protect sensitive components from damage and latchup which may result from such transient events. The SLVU2.8 can be configured to protect either one unidirectional line or two (one line pair) high-speed data lines. The options for connecting the devices are as follows: 1 2 Protection of one unidirectional line 1 . Protection of one unidirectional I/O line: Protection of one data line is achieved by connecting pin 3 to the protected line, and pins 1 and 2 to ground. This connection option will allow the device to operate on lines with positive polarity signal transitions (during normal operation). In this configuration, the device adds a maximum loading capacitance of 100pF. During positive duration transients, the internal TVS diode will be reversed biased and will act in the avalanche mode, conducting the transient current from pin 3 to 1. The transient will be clamped at or below the rated clamping voltage of the device. For negative duration transients, the internal steering diode is forward biased, conducting the transient current from pin 2 to 3. The transient is clamped below the rated forward voltage drop of the diode. Low capacitance protection of one high-speed line pair 2. Low capacitance protection of one differential line pair: Protection of a high-speed differential line pair is achieved by connecting two devices in antiparallel. Pin 1 of the first device is connected to line 1 and pin 2 is connected to line 2. Pin 2 of the second device is connected to line 1 and pin 1 is connected to line 2 as shown. Pin 3 must be left open on both devices. During negative duration transients, the first device will conduct from pin 2 to 1. The steering diode conducts in the forward direction while the TVS will avalanche and conduct in the reverse direction. During positive transients, the second device will conduct in the same manner. In this configuration, the total loading capacitance is the sum of the capacitance (between pins 1 and 2) of each device (typically <10pF) making this configuration suitable for high-speed interfaces such as 10/100 Ethernet (See application note SI98-02). © 2008 Semtech Corp. 3 EPD TVS Characteristics The SLVU2.8 is constructed using Semtech’s proprietary EPD technology. The structure of the EPD TVS is vastly different from the traditional pn-junction devices. At voltages below 5V, high leakage current and junction capacitance render conventional avalanche technology impractical for most applications. However, by utilizing the EPD technology, the SLVU2.8 can effectively operate at 2.8V while maintaining excellent electrical characteristics. The EPD TVS employs a complex nppn structure in contrast to the pn structure normally found in traditional silicon-avalanche TVS diodes. The EPD mechanism is achieved by engineering the center region of the device such that the reverse biased junction does 5 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Applications Information (continued) not avalanche, but will “punch-through” to a conducting state. This structure results in a device with superior dc electrical parameters at low voltages while maintaining the capability to absorb high transient currents. The IV characteristic curve of the EPD device is shown in Figure 1. The device represents a high impedance to the circuit up to the working voltage (VRWM). During a transient event, the device will begin to conduct as it is biased in the reverse direction. When the punchthrough voltage (VPT) is exceeded, the device enters a low impedance state, diverting the transient current away from the protected circuit. When the device is conducting current, it will exhibit a slight “snap-back” or negative resistance characteristic due to its structure. This must be considered when connecting the device to a power supply rail. To return to a non-conducting state, the current through the device must fall below the snap-back current (approximately < 50mA). SLVU2.8 Laser Diode Protection Circuit Board Layout Recommendations for Suppression of ESD. Good circuit board layout is critical for the suppression of ESD induced transients. The following guidelines are recommended: z Place the SLVU2.8 near the input terminals or connectors to restrict transient coupling. z Minimize the path length between the TVS and the protected line. z Minimize all conductive loops including power and ground loops. z The ESD transient return path to ground should be kept as short as possible. z Never run critical signals near board edges. z Use ground planes whenever possible. IPP ISB IPT VBRR IR VRWM VSB VPT VC IBRR 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. EPD TVS IV Characteristic Curve © 2008 Semtech Corp. 6 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Typical Applications 10/100 Ethernet Protection Circuit (Reference Semtech Application Note SI98-02 for more information) 10/100 Ethernet “Enhanced” Lightning Protection Circuit (Reference Semtech Application Note SI98-02 for more information) © 2008 Semtech Corp. 7 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Applications Information - SPICE Model 0.6 nH SLVU2.8 Spice Model SLVU2.8 Spice Parameters © 2008 Semtech Corp. Parameter Unit D1 (T VS) D2 (LCR D) IS Amp 6.09E-14 8.57E-9 BV Volt 3.4 420 VJ Volt 13.8 0.62 RS Ohm 0.389 0.15 IB V A mp 10E-3 10E-3 CJO Farad 24.75E-12 3.15E-12 TT sec 2.541E-9 2.541E-9 M -- 0.145 0.113 N -- 1.1 1.1 EG eV 1.11 1.11 8 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Outline Drawing - SOT23 D A DIM e1 A A1 A2 b c D E E1 e e1 L L1 N 0 aaa bbb H 3 B E1 GAUGE PLANE SEATING PLANE E 0 c 0.25 C L L1 DETAIL A 1 2 bxN bbb e A2 A DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX .035 .000 .035 .012 .003 .110 .082 .047 .015 0° .037 .114 .093 .051 .075 .037 .020 .022 3 .004 .008 .044 .004 .040 .020 .007 .120 .104 .055 .024 8° 0.89 1.12 0.01 0.10 0.88 0.95 1.02 0.30 0.51 0.08 0.18 2.80 2.90 3.04 2.10 2.37 2.64 1.20 1.30 1.40 1.90 BSC 0.95 BSC 0.40 0.50 0.60 (0.55) 3 0° 8° 0.10 0.20 C A B 3X aaa C SEE DETAIL A SIDE VIEW SEATING PLANE A1 C NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. Land Pattern - SOT23 X Y DIM Z G Y C C E E1 G X Y Z DIMENSIONS INCHES MILLIMETERS (.087) .037 .075 .031 .039 .055 .141 (2.20) 0.95 1.90 0.80 1.00 1.40 3.60 E E1 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. © 2008 Semtech Corp. 9 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Marking U2.8 Ordering Information Part Number Lead Finish Qty per R eel R eel Size SLVU2.8.TC SnPb 3,000 7 Inch SLVU2.8.TCT Pb free 3,000 7 Inch Contact Information Semtech Corporation Protection Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 © 2008 Semtech Corp. 10 www.semtech.com