SMF3.3 3.3 Volt TVS Array For ESD and Latch-Up Protection PROTECTION PRODUCTS Description Features ESD protection for data lines to The SMF series of TVS arrays are designed to protect sensitive electronics from damage or latch-up due to ESD, lightning, and other voltage-induced transient events. Each device will protect up to four lines operating at 3.3 volts. The SMF3.3 is a solid-state devices designed specifically for transient suppression. It 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 traditional pn junction processes. They offer desirable characteristics for board level protection including fast response time, low clamping voltage and no device degradation. Mechanical Characteristics The SMF3.3 may be used to meet the immunity requirements of IEC 61000-4-2, level 4 (±15kV air, ±8kV contact discharge). The small SC70-5L package makes them ideal for use in portable electronics such as cell phones, PDAs, and notebook computers. EIAJ SC70-5L package Molding compound flammability rating: UL 94V-0 Marking : Marking Code Packaging : Tape and Reel Applications Circuit Diagram 1 IEC 61000-4-2 (ESD) ±15kV (air), ±8kV (contact) IEC 61000-4-4 (EFT) 40A (5/50ns) Small package for use in portable electronics Protects four I/O lines Working voltage: 3.3V Low leakage current Low operating and clamping voltages Solid-state EPD TVS technology Cellular Handsets and Accessories Cordless Phones Personal Digital Assistants (PDAs) Notebooks and Handhelds Portable Instrumentation Digital Cameras Peripherals MP3 Players Schematic & PIN Configuration 3 4 5 1 5 2 3 4 2 SC70-5L (Top View) Revision 01/15/08 1 www.semtech.com SMF3.3 PROTECTION PRODUCTS Absolute Maximum Rating R ating Symbol Value Units Peak Pulse Power (tp = 8/20µs) Pp k 40 Watts Peak Pulse Current (tp = 8/20µs) IP P 5 A ESD per IEC 61000-4-2 (Air) ESD per IEC 61000-4-2 (Contact) VESD 20 15 kV Lead Soldering Temperature TL 260 (10 seconds) o Operating Temperature TJ -55 to +125 o TSTG -55 to +150 o Storage Temperature C C C Electrical Characteristics SMF3.3 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 Steering Diode Forward Voltage VF IPP = 1A, tp = 8/20µs Ground to any I/O 2.4 V Junction Cap acitance Cj Each I/O p in and Ground VR = 0V, f = 1MHz 25 30 pF I/O to I/O VR = 0V, f = 1MHz 12 2008 Semtech Corp. 2 0.05 pF www.semtech.com SMF3.3 PROTECTION PRODUCTS Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve 110 1 100 % of Rated Power or I PP Peak Pulse Power - P PP (kW) 90 0.1 80 70 60 50 40 30 20 10 0 0 25 0.01 0.1 1 10 100 50 75 100 125 150 Ambient Temperature - TA (oC) 1000 Pulse Duration - tp (µs) Pulse Waveform Clamping Voltage vs. Peak Pulse Current 110 10.00 Waveform Parameters: tr = 8µs td = 20µs 90 Percent of IPP 80 70 8.00 Clamping Voltage - VC (V) 100 e-t 60 50 40 td = IPP/2 30 20 6.00 4.00 Waveform Parameters: tr = 8µs td = 20µs 2.00 10 0 0 5 10 15 20 25 0.00 30 0 1 2 Time (µs) 3 4 5 Forward Voltage vs. Forward Current 7 Capacitance vs. Reverse Voltage 7.00 30 f = 1MHz 6.00 5.00 Capacitance - Cj (pF) Forward Voltage- VF (V) 6 Peak Pulse Current - IPP (A) 4.00 3.00 Waveform Parameters: tr = 8µs td = 20µs 2.00 1.00 0.00 L to G 20 L to L 10 0 0 1 2 3 4 5 6 7 0 Forward Current - IF (A) 2008 Semtech Corp. 1 2 3 Reverse Voltage - VR (V) 3 www.semtech.com SMF3.3 PROTECTION PRODUCTS Typical Characteristics Insertion Loss S21, I/O to I/O Insertion Loss S21, I/O to Ground CH1 S21 LOG 3 dB/ REF 0 dB CH1 S21 STOP 3000.000000 MHz START. 030 MHz LOG START. 030 MHz 3 dB/ REF 0 dB STOP 3000.000000 MHz Analog Crosstalk (I/O to I/O) CH1 S21 LOG START. 030 MHz 2008 Semtech Corp. 20 dB/ REF 0 dB STOP 3000.000000 MHz 4 www.semtech.com SMF3.3 PROTECTION PRODUCTS Applications Information SMF Circuit Diagram Device Connection for Protection of Four Data Lines The SMF3.3 is designed to protect up to four unidirectional data lines. The device is connected as follows: 1 3 4 5 1. Unidirectional protection of four I/O lines is achieved by connecting pins 1, 3, 4, and 5 to the data lines. Pin 2 is 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. 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. 2 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. 5 www.semtech.com SMF3.3 PROTECTION PRODUCTS Applications Information SMF3.3 Typical Application Diagram Matte Tin Lead Finish Circuit Board Layout Recommendations for Suppression of ESD. 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. 6 www.semtech.com SMF3.3 PROTECTION PRODUCTS Outline Drawing - SC-70 5L A DIM e1 D H N EI ccc C 2X N/2 TIPS c GAGE PLANE 2X E/2 1 E 0.15 L (L1) 2 e DETAIL 01 A B D aaa C SEATING PLANE A2 A SEE DETAIL A A A1 A2 b c D E1 E e e1 L L1 N 01 aaa bbb ccc DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX .043 .000 .004 .028 .035 .039 .006 .012 .003 .009 .075 .079 .083 .045 .049 .053 .083 BSC .026 BSC .051 .010 .014 .018 (.017) 5 0° 8° .004 .004 .012 1.10 0.00 0.10 0.70 0.90 1.00 0.15 0.30 0.08 0.22 1.90 2.00 2.10 1.15 1.25 1.35 2.10 BSC 0.65 BSC 1.30 BSC 0.26 0.36 0.46 (0.42) 5 0° 8° 0.10 0.10 0.30 SIDE VIEW C A1 bxN bbb 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 MO-203, VARIATION AA. Land Pattern - SC-70 5L X DIM C G C G P X Y Z Z Y DIMENSIONS MILLIMETERS INCHES (.073) .039 .026 .016 .033 .106 (1.85) 1.00 0.65 0.40 0.85 2.70 P NOTES: 1. 2008 Semtech Corp. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. 7 www.semtech.com SMF3.3 PROTECTION PRODUCTS Marking Codes Part Number Marking Code SMF3.3 F03 5 4 F03 1 2 3 Ordering Information Part Number Lead Finish Qty per Reel R eel Size SMF3.3.TC SnPb 3,000 7 Inch SMF3.3.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. 8 www.semtech.com