SLVU2.8-4.T - Semtech Corp.

PRELIMINARY

1www.semtech.com

PROTECTION PRODUCTS

SLVU2.8-4

EPD TVS Diode Array

For ESD and Latch-Up Protection

Description Features

Circuit Diagram Schematic & PIN Configuration

Revision 1/18/2008

The SLV series of transient voltage suppressors are

designed to protect low voltage, state-of-the-art CMOS

semiconductors from transients caused by electro-

static discharge (ESD), cable discharge events (CDE),

lightning and other induced voltage surges.

The devices are constructed using Semtech’s propri-

etary EPD process technology. The EPD process pro-

vides low standoff voltages with significant reductions

in leakage currents and capacitance over silicon-

avalanche diode processes. The SLVU2.8-4 features

integrated low capacitance compensation diodes that

reduce the typical capacitance to 5pF per line. This,

combined with low leakage current, means signal

integrity is preserved in high-speed applications such

as 10/100 Ethernet.

The SLVU2.8-4 is in an SO-8 package and may be used

to protect two high-speed line pairs. The “flow-thru”

design minimizes trace inductance and reduces voltage

overshoot associated with ESD events. The low

clamping voltage of the SLVU2.8-4 minimizes the

stress on the protected IC.

The SLV series TVS diodes will meet the surge require-

ments of IEC 61000-4-2, Level 4.

Applications

Mechanical Characteristics

10/100 Ethernet

WAN/LAN Equipment

Switching Systems

Desktops, Servers, and Notebooks

Instrumentation

Base Stations

Analog Inputs

400 Watts peak pulse power (tp = 8/20µs)

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)

Protects two line pairs (four lines)

Comprehensive pin out for easy board layout

Low capacitance

Low leakage current

Low operating and clamping voltages

Solid-state EPD TVS process technology

JEDEC SO-8 package

Molding compound flammability rating: UL 94V-0

Marking : Part number, date code, logo

Packaging : Tape and Reel

SO-8 (Top View)

Pin 1, 3

Pin 2, 4

Pin 6, 8

Pin 5, 7

2 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS

SLVU2.8-4

Absolute Maximum Rating

Electrical Characteristics

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3 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS PRELIMINARY

PROTECTION PRODUCTS

SLVU2.8-4

Typical Characteristics

Non-Repetitive Peak Pulse Power vs. Pulse Time

100

110

0 25 50 75 100 125 150

Ambient Temperature - TA (oC)

% of Rated Power or IPP

Power Derating Curve

Pulse Waveform Clamping Voltage vs. Peak Pulse Current

100

110

0 5 10 15 20 25 30

Time (µs)

Percent of IPP

e-t

td = IPP/2

0.01

0.1

0.1 1 10 100 1000

Pulse Duration - tp (µs)

Peak Pulse Power - Ppk (kW)

0 5 10 15 20 25

Peak Pulse Current - IPP (A)

Clamping Voltage - VC (V)

Waveform

Parameters:

tr = 8µs

td = 20µs

CH1 S21 LOG 10 dB/ REF 0 dB

START .030 000 MHz STOP 3 000.000 000 MHz

Insertion Loss S21Normalized Capacitance vs. Reverse Voltage

0.2

0.4

0.6

0.8

1.2

1.4

1.6

00.511.522.53

Reverse Voltage - VR (V)

CJ(VR) / CJ(VR=0)

f = 1 MHz

4 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS

SLVU2.8-4

SLVU2.8-4 Circuit Diagram

Low Capacitance Protection of Two Differential Line

Pairs

Device Connection for Protection of Four Data Lines

Electronic equipment is susceptible to transient distur-

bances 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 SLVU2.8-4 is designed to

protect sensitive components from damage and latch-

up which may result from such transient events. The

SLVU2.8-4 can be configured to protect two high-

speed line pairs. The device is connected as follows:

1. Protection of two high-speed line pairs:

The SLVU2.8-4 is designed such that the data lines

are routed through the device. The first line pair

enters at pins 1 and 2 and exit at pins 8 and 7

respectively. The second line pair enters at pins 3

and 4 and exits at pins 6 and 5. The traces must

be connected at the bottom of the device as

shown.

Circuit Board Layout Recommendations for Suppres-

sion of ESD.

Good circuit board layout is critical for the suppression

of ESD induced transients. The following guidelines are

recommended:

zPlace the SLVU2.8-4 near the input terminals or

connectors to restrict transient coupling.

zMinimize the path length between the TVS and the

protected line.

zMinimize all conductive loops including power and

ground loops.

zThe ESD transient return path to ground should be

kept as short as possible.

zNever run critical signals near board edges.

zUse ground planes whenever possible.

Line 1

Line 3

Line 4

Line 2

8Line 1

Line 3

Line 4

Line 2

Applications Information

5 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS PRELIMINARY

PROTECTION PRODUCTS

SLVU2.8-4

10/100 Ethernet Protection Circuit

Typical Applications

6 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS

SLVU2.8-4

Applications Information (continued)

IPP

ISB

IPT

RWM VV PT VC

VBRR

IBRR

EPD TVS IV Characteristic Curve

EPD TVS Characteristics

The SLVU2.8-4 is constructed using Semtech’s propri-

etary 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 SLVU2.8-4 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 tradi-

tional silicon-avalanche TVS diodes. The EPD mecha-

nism 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 conduct-

ing state. This structure results in a device with supe-

rior 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 punch-

through 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).

7 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS PRELIMINARY

PROTECTION PRODUCTS

SLVU2.8-4

Applications Information - SPICE Model

SLVU2.8-4 Spice Model

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8 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS

SLVU2.8-4

Land Pattern - SO-8

Outline Drawing - SO-8

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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.

.050 BSC

.236 BSC

.010

.150

.189

.154

.193

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0.25

1.27 BSC

6.00 BSC

3.90

4.90

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3.80

4.80

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4.00

5.00

0.51

(.041)

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0°

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0.20

0.10

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0.17

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DIM MIN

MILLIMETERS

NOM

DIMENSIONS

INCHES

MIN MAX MAXNOM

(.205) (5.20)

.118

1.27

.050

0.60.024

2.20.087

7.40.291

INCHES

DIMENSIONS

DIM

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.

9 2008 Semtech Corp. www.semtech.com

PROTECTION PRODUCTS PRELIMINARY

PROTECTION PRODUCTS

SLVU2.8-4

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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Note:

(1) Lead-Free Product

SC YYWW

SLVU2.8

-4

Marking

Note:

(1) yyww = Date Code

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