SRDA05-6

SRDA05-6 SEMTECH | Alldatasheet

Document overview

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Technical content

1 www.semtech.com PROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 Low Capacitance TVS Diode Array Description Features Circuit Diagram Schematic and PIN Configuration Revision 01/15/08 RailClamps are surge rated diode arrays designed to protect high speed data interfaces. The SR series has been specifically designed to protect sensitive compo- nents which are connected to data and transmission lines from overvoltage caused by electrostatic dis- charge (ESD), electrical fast transients (EFT), and lightning. The unique design of the SRDA series devices incorpo- rates surge rated, low capacitance steering diodes and a TVS diode in a single package. During transient conditions, the steering diodes direct the transient to either the positive side of the power supply line or to ground. The internal TVS diode prevents over-voltage on the power line, protecting any downstream compo- nents. The low capacitance array configuration allows the user to protect six high-speed data or transmission lines. The low inductance construction minimizes voltage overshoot during high current surges.

Applications

Mechanical Characteristics ‹ USB Power & Data Line Protection ‹ T1/E1 secondary IC Side Protection ‹ Token Ring ‹ HDSL, SDSL secondary IC Side Protection ‹ Video Line Protection ‹ Microcontroller Input Protection ‹ Base stations ‹ I2C Bus Protection ‹ Transient protection for high-speed data lines to 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 six I/O lines and power supply line ‹ Low capacitance (<15pF) for high-speed interfaces ‹ Low operating & clamping voltages ‹ Solid-state technology ‹ JEDEC SO-8 package ‹ UL 497B listed ‹ Molding compound flammability rating: UL 94V-0 ‹ Marking : Part number, date code, logo ‹ Packaging : Tube or Tape and Reel S0-8 (Top View) I/O 1 I/O 2 I/O 3 I/O 4 I/O 5 I/O 6 +VREF GND1 4 5

2 2008 Semtech Corp. www.semtech.com PROTECTION PRODUCTSPROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 Absolute Maximum Rating

Electrical Characteristics

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3 2008 Semtech Corp. www.semtech.com PROTECTION PRODUCTSPROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 6-50ADRS retemaraPl obmySs noitidnoCm uminiMl acipyTm umixaMs tinU egatloVffO-dnatSesreveRV MWR 5V egatloVnwodkaerBesreveRV RB It Am1=6 V tnerruCegakaeLesreveRI R V MWR C°52=T,V5=0 1A µ egatloVgnipmalCV C I PP t,A1= p sµ02/8=8 .9V egatloVgnipmalCV C I PP t,A01= p sµ02/8=2 1V egatloVgnipmalCV C I PP t,A52= p sµ02/8=0 2V tnerruCesluPkaePI PP tp sµ02/8=5 2A ecnaticapaCnoitcnuJC j dnasnipO/IneewteB dnuorG VR zHM1=f,V0= 85 1F p snipO/IneewteB VR zHM1=f,V0= 4F p Electrical Characteristics (continued)

4 2008 Semtech Corp. www.semtech.com PROTECTION PRODUCTSPROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 Typical Characteristics Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve 0.01 0.1 0.1 1 10 100 1000 Pulse Duration - tp (µs) Peak Pulse Power - Ppk (kW) 100 110 0 25 50 75 100 125 150 Ambient Temperature - T A (oC) % of Rated Power or IPP Clamping Voltage vs. Peak Pulse Current 100 110 0 5 10 15 20 25 30 Time (µs) Percent of IPP e td = IPP/2 Waveform Parameters: tr = 8µs td = 20µs Pulse Waveform Variation of Capacitance vs. Reverse Voltage Forward Voltage vs. Forward Current -14 -12 -10 0123456 Reverse Voltage - VR (V) % Change in Capacitance 0 5 10 15 20 25 30 35 40 45 50 Forward Current - I F (A) Forward Voltage - VF (V) Waveform Parameters: tr = 8µs td = 20µs 0 5 10 15 20 25 30 Peak Pulse Current - I PP (A) Clamping Voltage - VC (V) SRDA05-6 SRDA3.3-6 Waveform Parameters: tr = 8µs td = 20µs

5 2008 Semtech Corp. www.semtech.com PROTECTION PRODUCTSPROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 Device Connection Options for Protection of Six High- Speed Lines The SRDA TVS is designed to protect four data lines from transient overvoltages by clamping them to a fixed reference. When the voltage on the protected line exceeds the reference voltage (plus diode V F) the steering diodes are forward biased, conducting the transient current away from the sensitive circuitry. Data lines are connected at pins 1, 2, 4, 5, 6 and 7. The negative reference is connected at pin 8. These pins should be connected directly to a ground plane on the board for best results. The path length is kept as short as possible to minimize parasitic inductance. The positive reference is connected at pins 2 and 3. In the case of the SRDA3.3-6, 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 (V SB) as the device can latch on as described below. EPD TVS Characteristics These devices are constructed using Semtech’s proprietary EPD technology. By utilizing the EPD tech- nology, the SRDA3.3-6 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 tradi- tional 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 (V RWM). During an ESD event, the device will begin to conduct and will enter a low impedance state when the punch through voltage PT) is exceeded. Unlike a conventional device, the low voltage TVS will exhibit a slight negative resistance characteristic as it conducts current. This characteris- tic aids in lowering the clamping voltage of the device, but must be considered in applications where DC voltages are present. When the TVS is conducting current, it will exhibit a slight “snap-back” or negative resistance characteris- tics due to its structure. This point is defined on the Data Line Protection Using Internal TVS Diode as Reference Applications Information curve by the snap-back voltage (V SB) and snap-back current (ISB). To return to a non-conducting state, the current through the device must fall below the I SB (approximately <50mA) and the voltage must fall below the V SB (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. EPD TVS IV Characteristic Curve IPP ISB IPT IR VRWM VV PT VC VBRR IBRR SB

7 2008 Semtech Corp. www.semtech.com PROTECTION PRODUCTSPROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 Applications Information (continued) the current will be directed through the integrated TVS diode to ground. The total clamping voltage seen by the protected IC due to this path will be: V C = V F(RailClamp) + V TVS This is given in the data sheet as the rated clamping voltage of the device. For an SRDA05-6 the typical clamping voltage is <16V at I PP =30A. The diodes internal to the RailClamp are low capacitance, fast switching devices that are rated to handle high tran- sient currents and maintain excellent forward voltage characteristics. Using the RailClamp does not negate the need for good board layout. All other inductive paths must be consid- ered. The connection between the positive supply and the SRDA and from the ground plane to the SRDA must be kept as short as possible. The path between the SRDA and the protected line must also be mini- mized. The protected lines should be routed directly to the SRDA. Placement of the SRDA on the PC board is also critical for effective ESD protection. The device should be placed as close as possible to the input connector. The reason for this is twofold. First, inductance resists change in current flow. If a signifi- cant inductance exists between the connector and the TVS, the ESD current will be directed elsewhere (lower resistance path) in the system. Second, the effects of radiated emissions and transient coupling can cause upset to other areas of the board even if there is no direct path to the connector. By placing the TVS close to the connector it will divert the ESD current immedi- ately and absorb the ESD energy before it can be coupled into nearby traces. (Reference Semtech application note SI99-01 for further information on board layout) 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 com- pared 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.

8 2008 Semtech Corp. www.semtech.com PROTECTION PRODUCTSPROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 Outline Drawing - SO-8 Land Pattern - SO-8 bxN 2X N/2 TIPS SEATING aaa C E/22X N A D bbb C A-B D ccc C e/2 SEE DETAIL A SIDE VIEW A B C De DETAIL A c L (L1) 01 0.25 GAGE PLANE h h H PLANE 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. -B- CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). DATUMS AND TO BE DETERMINED AT DATUM PLANE NOTES: 2. -A- -H- REFERENCE JEDEC STD MS-012, VARIATION AA.4. .050 BSC .236 BSC .010 .150 .189 .154 .193 .012 - 0.25

1.27 BSC

6.00 BSC

3.90 4.90 .157 .197 3.80 4.80 .020 0.31 4.00 5.00 0.51 (.041) .004 .008 .028 .016 .007 .049 .004 .053 8° 0° 0.20 0.10 - 8° 0.40 0.17 1.25 0.10 .041 .010 .069 .065 .010 1.35 (1.04) 0.72 1.04 0.25 - 1.75 1.65 0.25 N bbb aaa ccc A b D E L h e c DIM MIN MILLIMETERS NOM DIMENSIONS INCHES MIN MAX MAX NOM E (.205) (5.20) ZG Y P (C) 3.00.118 1.27.050 0.60.024 2.20.087 7.40.291 X INCHES DIMENSIONS Z P Y X DIM C G MILLIMETERS THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. NOTES: REFERENCE IPC-SM-782A, RLP NO. 300A.2.

9 2008 Semtech Corp. www.semtech.com PROTECTION PRODUCTSPROTECTION PRODUCTS SRDA3.3-6 and SRDA05-6 Contact Information Semtech Corporation Protection Products Division

200 Flynn Road, Camarillo, CA 93012

Phone: (805)498-2111 FAX (805)498-3804

Ordering Information

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