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. u 400 Watts peak pulse power (tp = 8/20s) u Transient protection for high speed data lines to The devices are constructed using Semtechs 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. u u u u u u IEC 61000-4-2 (ESD) 15kV (air), 8kV (contact) IEC 61000-4-4 (EFT) 40A (tp = 5/50ns) IEC 61000-4-5 (Lightning) 24A (tp = 8/20s) 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 u u u u 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 u u u u u u 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 9/2000 1 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Absolute Maximum Rating R ating Symbo l Value Units Peak Pulse Pow er (tp = 8/20ms) Pp k 400 Watts Peak Pulse Current (tp = 8/20ms) I PP 24 A Lead Sold ering Temp erature TL 260 (10 second s) 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 Par ame te r Symbo l Co nd itio ns VRWM Pin 3 to 1 or Pin 2 to 1 Punch -Th rough Voltage V PT IPT = 2 A , Pin 3 to 1 3.0 V Snap -Back Voltage VSB ISB = 50mA , Pin 3 to 1 2.8 V Reverse Leakage Current IR V RWM = 2.8V, T=25C Pin 3 to 1 or Pin 2 to 1 1 A Clamp ing Voltage VC IPP = 2A , tp = 8/20 s Pi n 3 t o 1 3.9 V Clamp ing Voltage VC IPP = 5A , tp = 8/20 s Pi n 3 t o 1 7 V Clamp ing Voltage VC IPP = 24A , tp = 8/20 s Pi n 3 t o 1 12.5 V Clamp ing Voltage VC IPP = 5A , tp = 8/20 s Pi n 2 t o 1 8.5 V Clamp ing Voltage VC IPP = 24A , tp = 8/20 s Pi n 2 t o 1 15 V Junction Cap acitance Cj Pi n 3 t o 1 & 2 (Pin 1 & 2 tied togeth er) V R = 0V, f = 1MHz 70 100 pF Junction Cap acitance Cj Pin 2 to 1 (p in 3 N .C.) V R = 0V, f = 1MHz 5 10 pF Reverse Breakd ow n Voltage V BR IT= 10 A , Pin 3 to 2 Reverse Leakage Current IR D V RWM = 2.8V, T=25C Pi n 3 t o 2 1 A Forw ard Voltage VF IF= 1A , Pin 2 to 3 2 V Reverse Stand -Off Voltage Minimum Typ ical Maximum Units 2.8 V Ste e r ing Dio d e Char acte r istics a 2000 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 90 % of Rated Power or I PP Peak Pulse Power - PPP (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 75 100 125 150 Clamping Voltage vs. Peak Pulse Current 18 110 Waveform Parameters: tr = 8s td = 20s 90 80 70 e 60 16 Clamping Voltage - VC (V) 100 Percent of IPP 50 Ambient Temperature - TA (oC) Pulse Duration - tp ( s) -t 50 40 td = IPP/2 30 Pin 2 to 1 14 12 10 Pin 3 to 1 8 6 Waveform Parameters: tr = 8s td = 20s 4 20 2 10 0 0 0 5 10 15 20 25 0 30 a 2000 Semtech Corp. 5 10 15 20 25 30 35 Peak Pulse Current - IPP (A) Time (s) 3 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). a 2000 Semtech Corp. 3 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: l Place the SLVU2.8 near the input terminals or connectors to restrict transient coupling. l Minimize the path length between the TVS and the protected line. l Minimize all conductive loops including power and ground loops. l The ESD transient return path to ground should be kept as short as possible. l Never run critical signals near board edges. l Use ground planes whenever possible. 4 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Applications Information (continued) EPD TVS Characteristics ,PP The SLVU2.8 is constructed using Semtechs 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. ,6% ,37 9%55 ,5 95:0 96% 937 9& ,%55 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 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. EPD TVS VI Characteristic Curve 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). a 2000 Semtech Corp. 5 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) a 2000 Semtech Corp. 6 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Outline Drawing - SOT23 Land Pattern - SOT23 Note 1 : Grid placement courtyard is 8 x 8 elements (4mm x 4mm) in accordance with the international grid detailed in IEC Publication 97. a 2000 Semtech Corp. 7 www.semtech.com SLVU2.8 PROTECTION PRODUCTS Ordering Information Par t Numbe r Wo r king Vo ltage Qty p e r R e e l R e e l Size SLVU2.8.TC 2.8V 3,000 7 Inch SLVU2.8.TG 2.8V 10,000 13 Inch Contact Information Semtech Corporation Protection Products Division 652 Mitchell Rd., Newbury Park, CA 91320 Phone: (805)498-2111 FAX (805)498-3804 a 2000 Semtech Corp. 8 www.semtech.com