uClamp3304A µClampTM 4-Line ESD protection Array PROTECTION PRODUCTS - MicroClampTM Description Features The µClampTM series of TVS arrays are designed to protect sensitive electronics from damage or latch-up due to ESD. They are designed for use in applications where board space is at a premium. Each device requires less than 2.9mm2 of PCB area and will protect up to four lines. They are unidirectional devices and may be used on lines with positive signal polarities. The µclampTM3304A is constructed using Semtech’s proprietary EPD process technology. The EPD process provides low standoff voltages with significant reductions in leakage currents and capacitance over silicon-avalanche diode processes. They feature a true operating voltage of 3.3 volts for superior protection when compared to traditional pn junction devices. These devices may be used to meet the immunity requirements of IEC 61000-4-2, level 4. They offer desirable characteristics for board level protection including fast response time, low operating and clamping voltage, and no device degradation. The small SC89 package makes them ideal for use in portable electronics such as cell phones, PDAs, notebook computers, and digital cameras. Transient protection for data lines to IEC 61000-4-2 (ESD) ±15kV (air), ±8kV (contact) IEC 61000-4-4 (EFT) 40A (5/50ns) Protects four unidirectional I/O lines 1.7 x 1.7 x 0.6mm Ultra-small SC-89 package (1.7 0.6mm) 2 requires less than 2.9mm of PCB area Working voltage: 3.3V Low leakage current Low operating and clamping voltages Solid-state silicon-avalanche technology Mechanical Characteristics SC-89 (SOT-666) package Molding compound flammability rating: UL 94V-0 Marking: Marking Code Lead Finish: Matte Tin RoHS Compliant Weight: 2.9mg (typical) Packaging: Tape and Reel Applications Dimensions Cellular Handsets and Accessories Cordless Phones Notebooks and Handhelds Portable Instrumentation Digital Cameras Peripherals MP3 Players Schematic & PIN Configuration 1.70 0.50 1.25 1.70 0.30 0.60 Maximum Dimensions (mm) Revision 01/18/08 SC-89 (Top View) 1 www.semtech.com µClamp3304A PROTECTION PRODUCTS Absolute Maximum Rating R ating Symbol Value Units Peak Pulse Power (tp = 8/20µs) Pp k 40 Watts Maximum Peak Pulse Current (tp = 8/20µs) Ip p 5 Amps ESD per IEC 61000-4-2 (Air) ESD per IEC 61000-4-2 (Contact) V PP +/- 20 +/- 15 kV Lead Soldering Temperature TL 260 (10 sec.) °C Operating Temperature TJ -55 to +125 °C TSTG -55 to +150 °C Storage Temperature Electrical Characteristics (T=25oC) 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 Clamp ing Voltage VC Clamp ing Voltage 0.5 µA IPP = 1A, tp = 8/20µs 5.5 V VC IPP = 5A, tp = 8/20µs 8.0 V Forward Clamp ing Voltage VF IPP = 1A, tp = 8/20µs 2.4 V 30 pF Cj I/O p in to Gnd VR = 0V, f = 1MHz 22 Junction Cap acitance I/O p in to Gnd VR = 3.3V, f = 1MHz 14 2008 Semtech Corp. 2 0.05 pF www.semtech.com µClamp3304A PROTECTION PRODUCTS Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve 1 110 100 % of Rated Power or IPP Peak Pulse Power - P PP (kW) 90 0.1 80 70 60 50 40 30 20 10 0 0.01 0.1 1 10 100 0 1000 25 50 75 100 125 150 o Ambient Temperature - TA ( C) Pulse Duration - tp (µs) Clamping Voltage vs. Peak Pulse Current Junction Capacitance vs. Reverse Voltage 12 25.0 f = 1 MHz Clamping Voltage - VC (V) 10 20.0 Capacitance - Cj (pF) 8 6 4 Waveform Parameters: tr = 8µs td = 20µs 2 15.0 10.0 5.0 0 0 1 2 3 4 0.0 5 0 Peak Pulse Current - IPP (A) Forward Voltage vs Forward Current 0.5 1 1.5 2 2.5 Reverse Voltage - VR (V) 3 3.5 ESD Clamping (8kV Contact per IEC 61000-4-2) 7 Forward Voltage - VF (V) 6 5 4 3 2 Waveform Parameters: tr = 8µs td = 20µs 1 0 0 1 2 3 4 5 6 Forward Current - IF (A) 2008 Semtech Corp. 3 www.semtech.com µClamp3304A PROTECTION PRODUCTS Applications Information Circuit Diagram Device Connection for Protection of Four Data Lines These devices are designed to protect up to four unidirectional data lines. The device is connected as follows: 1 3 4 6 1. Unidirectional protection of four I/O lines is achieved by connecting pins 1, 3, 4, and 6 to the data lines. Pins 2 and 5 are connected to ground. The ground connection should be made directly to the ground plane for best results. The path length is kept as short as possible to reduce the effects of parasitic inductance in the board traces. 2, 5 Due to the “snap-back” characteristics of the low voltage TVS, it is not recommended that any of the I/O lines be directly connected to a DC source greater than snap-back votlage (VSB) as the device can latch on as described below. Protection of Four Unidirectional Lines EPD TVS Characteristics The SMF3.3 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 SMF3.3 can effectively operate at 3.3V 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. 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. 2008 Semtech Corp. When the TVS is conducting current, it will exhibit a slight “snap-back” or negative resistance characteristics due to its structures. This point is defined on the curve by the snap-back voltage (VSB) and snap-back 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. 4 www.semtech.com µClamp3304A PROTECTION PRODUCTS Typical Applications uClamp3304A Circuit Board Layout Recommendations for Suppression of ESD. 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. Good circuit board layout is critical for the suppression of ESD induced transients. The following guidelines are recommended: z Place the TVS 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. 2008 Semtech Corp. 5 www.semtech.com µClamp3304A PROTECTION PRODUCTS Applications Information - Spice Model Figure 1 - µClamp3304A Spice Model Table 1 - µClamp3304A Spice Parameters 2008 Semtech Corp. Parameter Unit D1 (T VS) D2 (LCR D) IS Amp 1.00E-20 1.00E-20 BV Volt 3.47 8 VJ Volt 14 0.70 RS Ohm 0.737 0.795 IB V Amp 1.0E-3 1.0E-3 CJO Farad 14.53E-12 6E-12 TT sec 2.541E-9 2.541E-9 M -- 0.152 0.152 N -- 1.1 1.1 EG eV 1.11 1.11 6 www.semtech.com µClamp3304A PROTECTION PRODUCTS Outline Drawing - SC-89 (SOT-666) D A D N E/2 E1 E L 2 1 e c Nxb B aaa C A-B D A DIM A b c D E E1 e L L1 N aaa C L1 DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX .019 .024 .005 .012 .003 .007 .059 .063 .067 .061 .063 .067 .043 .047 .049 .020 BSC .003 .008 .012 .003 .006 .008 6 .004 0.50 0.60 0.15 0.30 0.10 0.18 1.50 1.60 1.70 1.55 1.60 1.70 1.10 1.20 1.25 0.50 BSC 0.10 0.20 0.30 0.10 0.15 0.20 6 0.10 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. Land Pattern - SC-89 (SOT-666) X Y Z C DIM C P G X Y Z G Y DIMENSIONS INCHES MILLIMETERS (.057) .020 .024 .012 .033 .090 (1.45) 0.50 0.60 0.30 0.85 2.30 P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 2008 Semtech Corp. 7 www.semtech.com µClamp3304A PROTECTION PRODUCTS Marking Code Ordering Information SS Part Number Working Voltage uClamp 3304A.TCT 3.3V Device Qty per Marking Reel SS 3,000 Reel Size 7 Inch Note: Lead finish is lead-free matte tin MicroClamp, uClamp and µClamp are trademarks of Semtech Corporation Note: (1) Device is symmetrical so there is no pin 1 identifier Tape and Reel Specification SS SS SS Tape Specifications and Device Orientation Contact Information Semtech Corporation Protection Products Division 200 Flynn Rd., Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 2008 Semtech Corp. 8 www.semtech.com