™
EPD TVS™ Diodes For
ESD and Latch-Up Protection
PROTECTION PRODUCTS
Description
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 SLVE2.8 & SLVG2.8
are in a SOT-143 package and have a low 2.8V work-
ing voltage. They may be used to protect one line in
differential or common mode. The “flow-thru” design
minimizes trace inductance and reduces voltage
overshoot associated with ESD events.
The SLV 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 SLV minimizes the stress on the pro-
tected IC.
The SLV series TVS diodes will exceed the surge re-
quirements of IEC 61000-4-2, Level 4.
SLVE2.8 & SLVG2.8
Features
!
300 Watts peak pulse power (tp = 8/20µs)
!
Transient protection for low voltage data lines to
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 = 8/20µs)
Protects one line
Comprehensive pin out for easy board layout
Low capacitance
Low leakage current
Low operating and clamping voltages
Solid-state EPD TVS process technology
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Mechanical Characteristics
JEDEC SOT-143 package
Molding compound flammability rating: UL 94V-0
Marking : Marking code
Packaging : Tape and Reel per EIA 481
Applications
ESD and Latch-up Protection
Analog Inputs
WAN/LAN Equipment
Low Voltage ASICs
Desktops, Servers, Notebooks & Handhelds
Portable Instrumentation
Base Stations
Laser Diode Protection
Schematic & Pin Configuration
Schematic & PIN Configuration
4
1
1
4
2
3
2
3
SLVG2.8 (Top View)
Revision 1/18/2001
1
SLVE2.8 (Top View)
www.semtech.com
SLVE2.8 & SLVG2.8
PROTECTION PRODUCTS
Absolute Maximum Rating
R ating
Peak Pulse Power (tp = 8/20
µ
s)
Peak Pulse Current (tp = 8/20
µ
s)
Lead Soldering Temperature
Operating Temperature
Storage Temperature
Symbol
P
p k
I
P P
T
L
T
J
T
STG
Value
300
24
260 (10 seconds)
-55 to +125
-55 to +150
Units
Watts
A
o
C
C
C
o
o
Electrical Characteristics
SLVE2.8
Parameter
Reverse Stand-Off Voltage
Punch-Through Voltage
Snap-Back Voltage
Reverse Leakage Current
Clamping Voltage
Clamping Voltage
Clamping Voltage
Junction Capacitance
Symbol
V
RWM
V
PT
V
SB
I
R
V
C
V
C
V
C
C
j
I
PT
= 2µA
I
SB
= 50mA
V
RWM
= 2.8V, T=25°C
I
PP
= 1A, tp = 8/20µs
I
PP
= 5A, tp = 8/20µs
I
PP
= 24A, tp = 8/20µs
Line-to-Line
V
R
= 0V, f = 1MHz
3.0
2.8
1
4.1
5.3
15
100
Conditions
Minimum
Typical
Maximum
2.8
Units
V
V
V
µA
V
V
V
pF
SLVG2.8
Parameter
Reverse Stand-Off Voltage
Punch-Through Voltage
Snap-Back Voltage
Reverse Leakage Current
Clamping Voltage
Clamping Voltage
Clamping Voltage
Junction Capacitance
2001 Semtech Corp.
Symbol
V
RWM
V
PT
V
SB
I
R
V
C
V
C
V
C
C
j
Conditions
Minimum
Typical
Maximum
2.8
Units
V
V
V
I
PT
= 2µA
I
SB
= 50mA
V
RWM
= 2.8V, T=25°C
I
PP
= 1A, tp = 8/20µs
I
PP
= 5A, tp = 8/20µs
I
PP
= 24A, tp = 8/20µs
Line-to-Line
V
R
= 0V, f = 1MHz
2
3.0
2.8
1
4.1
5.3
15
50
µA
V
V
V
pF
www.semtech.com
SLVE2.8 & SLVG2.8
PROTECTION PRODUCTS
Typical Characteristics
Non-Repetitive Peak Pulse Power vs. Pulse Time
10
Peak Pulse Power - P
PP
(kW)
110
100
90
% of Rated Power or I
PP
80
70
60
50
40
30
20
10
0.01
0.1
1
10
Pulse Duration - tp (µs)
µ
100
1000
0
0
25
50
75
100
o
Power Derating Curve
1
0.1
125
150
Ambient Temperature - T
A
( C)
Pulse Waveform
110
100
90
80
Percent of I
PP
70
60
50
40
30
20
10
0
0
5
10
15
Time (µs)
µ
20
25
30
td = I
PP
/2
e
-t
Clamping Voltage vs. Peak Pulse Current
18
Waveform
Parameters:
tr = 8
µ
s
td = 20
µ
s
16
Clamping Voltage - V (V)
C
14
12
10
SLVE2.8
8
6
4
2
0
0
5
10
15
20
25
30
35
Peak Pulse Current - I
PP
(A)
Waveform
Parameters:
tr = 8
µ
s
td = 20
µ
s
SLVG2.8
2001 Semtech Corp.
3
www.semtech.com
SLVE2.8 & SLVG2.8
PROTECTION PRODUCTS
Applications Information
Device Connection
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 SLV series is designed to
protect sensitive components from damage and latch-
up which may result from such transient events. The
SLVG2.8 is designed to protect one unidirectional line
while the SLVE2.8 is designed to protect one bidirec-
tional line (or two differential lines). The options for
connecting the devices are as follows:
"
Circuit Diagrams
4
1
1
4
2
SLVG2.8
3
2
3
"
SLVE2.8:
Common mode protection of one bidirec-
tional data line is achieved by connecting the data
line input/output at pins 2 and 3. Pins 1 and 4 are
connected to ground. For differential protection,
pins 1 & 4 can be connected to a second I/O line.
For best results, the ground connection should be
made directly to a ground plane on the board. The
path length should be kept as short as possible to
minimize parasitic inductance.
SLVG2.8:
Common mode protection of one unidi-
rectional line is achieved by connecting the line to
be protected at pins 2 & 3. Pins 1 & 4 are con-
nected to ground. For best results, the ground
connection should be made directly to a ground
plane on the board. The path length should be
kept as short as possible to minimize parasitic
inductance.
SLVE2.8
Common Mode Protection (SLVE2.8 & SLVG2.8)
4
1
Line
In
2
3
Line
Out
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:
"
Place the TVS near the input terminals or connec-
tors to restrict transient coupling.
"
Minimize the path length between the TVS and the
protected line.
"
Minimize all conductive loops including power and
ground loops.
"
The ESD transient return path to ground should be
kept as short as possible.
"
Never run critical signals near board edges.
"
Use ground planes whenever possible.
Differential Mode Protection (SLVE2.8 only)
Line 1
In
4
1
Line 1
Out
Line 2
In
2
3
Line 2
Out
2001 Semtech Corp.
4
www.semtech.com
SLVE2.8 & SLVG2.8
PROTECTION PRODUCTS
Applications Information
(continued)
EPD TVS
™
Characteristics
I
PP
The SLV series 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 SLVE2.8 & SLVG2.8 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 (V
RWM
). During a
transient event, the device will begin to conduct as it is
biased in the reverse direction. When the punch-
through voltage (V
PT
) 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).
I
SB
I
PT
V
BRR
I
R
V
RWM
V
SB
V
PT
V
C
I
BRR
EPD TVS VI Characteristic Curve
2001 Semtech Corp.
5
www.semtech.com
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