© Semiconductor Components Industries, LLC, 2007
June, 2007 - Rev. 5
1Publication Order Number:
SRDA05-4R2/D
SRDA05-4R2
Low Capacitance Surface
Mount TVS for High-Speed
Data Interfaces
The SRDA05-4 transient voltage suppressor is designed to protect
equipment attached to high speed communication lines from ESD,
EFT, and lightning.
Features
•SO-8 Package
•Peak Power - 500 Watts 8 x 20 mS
•ESD Rating:
IEC 61000-4-2 (ESD) 15 kV (air) 8 kV (contact)
IEC 61000-4-4 (EFT) 40 A (5/50 ns)
IEC 61000-4-5 (lightning) 23 (8/20 ms)
•UL Flammability Rating of 94 V-0
•Pb-Free Package is Available
Typical Applications
•High Speed Communication Line Protection
MAXIMUM RATINGS
Rating Symbol Value Unit
Peak Power Dissipation
8 x 20 mS @ TA = 25°C (Note 1)
Ppk 500 W
Junction and Storage Temperature Range TJ, Tstg - 55 to +150 °C
Lead Solder Temperature -
Maximum 10 Seconds Duration
TL260 °C
Stresses exceeding Maximum Ratings may damage the device. Maximum
Ratings are stress ratings only. Functional operation above the Recommended
Operating Conditions is not implied. Extended exposure to stresses above the
Recommended Operating Conditions may affect device reliability.
1. Non-repetitive current pulse 8 x 20 mS exponential decay waveform
SO-8 LOW CAPACITANCE
VOLTAGE SUPPRESSOR
500 WATTS PEAK POWER
6 VOLTS
MARKING DIAGRAM
SOIC-8
CASE 751
PLASTIC
PIN CONFIGURATION
AND SCHEMATIC
I/O 1 1
REF 1 2
REF 1 3
I/O 2 4
8 REF 2
7 I/O 4
6 I/O 3
5 REF 2
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†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
1
8
SRDA5
AYWWG
G
1
8
SRDA5 = Device Code
A = Assembly Location
Y = Year
WW = Work Week
G= Pb-Free Package
(Note: Microdot may be in either location)
Device Package
ORDERING INFORMATION
Shipping†
SRDA05-4R2 SO-8 2500/Tape & Reel
SRDA05-4R2G SO-8
(Pb-Free)
2500/Tape & Reel
SRDA05-4R2
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2
ELECTRICAL CHARACTERISTICS
Characteristic Symbol Min Typ Max Unit
Reverse Breakdown Voltage @ It = 1.0 mA VBR 6.0 - - V
Reverse Leakage Current @ VRWN = 5.0 V IRN/A - 10 mA
Maximum Clamping Voltage @ IPP = 1.0 A, 8 x 20 mSVCN/A - 9.8 V
Maximum Clamping Voltage @ IPP = 10 A, 8 x 20 mSVCN/A - 12 V
Between I/O Pins and Ground @ VR = 0 V, 1.0 MHz Capacitance - 10 15 pF
Between I/O Pins @ VR = 0 Volts, 1.0 MHz Capacitance - 5 8 pF
ELECTRICAL CHARACTERISTICS
(TA = 25°C unless otherwise noted)
UNIDIRECTIONAL (Circuit tied to Pins 1 and 3 or 2 and 3)
Symbol Parameter
IPP Maximum Reverse Peak Pulse Current
VCClamping Voltage @ IPP
VRWM Working Peak Reverse Voltage
IRMaximum Reverse Leakage Current @ VRWM
VBR Breakdown Voltage @ IT
ITTest Current
QVBR Maximum Temperature Coefficient of VBR
IFForward Current
VFForward Voltage @ IF
ZZT Maximum Zener Impedance @ IZT
IZK Reverse Current
ZZK Maximum Zener Impedance @ IZK
Uni-Directional TVS
IPP
IF
V
I
IR
IT
VRWM
VCVBR
VF
SRDA05-4R2
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3
TYPICAL CHARACTERISTICS
-100 0
9
Figure 1. Reverse Breakdown versus
Temperature
-50
T, TEMPERATURE (°C)
100 200
4
1
0
Figure 2. Reverse Leakage versus
Temperature
VZ, REVERSE BREAKDOWN (V)
8
7
6
5
4
3
2
1
0
-100 -50 50 100
T, TEMPERATURE (°C)
200
50 150
2
3
8
5
6
7
0 150
IR, REVERSE LEAKAGE (mA)
Figure 3. 8 x 20 ms Pulse Waveform
100
90
80
70
60
50
40
30
20
10
00204060
t, TIME (ms)
% OF PEAK PULSE CURRENT
tP
tr
PULSE WIDTH (tP) IS DEFINED
AS THAT POINT WHERE THE
PEAK CURRENT DECAY = 8 ms
PEAK VALUE IRSM @ 8 ms
HALF VALUE IRSM/2 @ 20 ms
80
Figure 4. Clamping Voltage versus Peak Pulse
Current
35
30
25
20
15
10
5
00204060
IPP
, PEAK PULSE CURRENT (A)
80
VC, CLAMPING VOLTAGE (V)
10 30 50 70 90
SRDA05-4R2
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4
APPLICATIONS INFORMATION
The SRDA05-4R2 is a low capacitance TVS diode array
designed to protect sensitive electronics such as
communications systems, computers, and computer
peripherals against damage due to ESD events or transient
overvoltage conditions. Because of its low capacitance, it
can be used in high speed I/O data lines. The integrated
design of the SRDA05-4R2 offers surge rated, low
capacitance steering diodes and a TVS diode integrated in a
single package (SO-8). If a transient condition occurs, the
steering diodes will drive the transient to the positive rail of
the power supply or to ground. The TVS device protects the
power line against overvoltage conditions avoiding damage
to the power supply and other downstream components.
SRDA05-4R2 Configuration Options
The SRDA05-4R2 is able to protect up to four data lines
against transient overvoltage conditions by driving them to
a fixed reference point for clamping purposes. The steering
diodes will be forward biased whenever the voltage on the
protected line exceeds the reference voltage (Vf or Vcc+Vf).
The diodes will force the transient current to bypass the
sensitive circuit.
Data lines are connected at pins 1, 4, 6 and 7. The negative
reference is connected at pins 5 and 8. These pins must be
connected directly to ground using a ground plane to
minimize the PCB's ground inductance. It is very important
to reduce the PCB trace lengths as much as possible to
minimize parasitic inductances.
Option 1
Protection of four data lines and the power supply using
Vcc as reference.
8
7
6
5
1
2
3
4
I/O 1
I/O 2
I/O 3
I/O 4
VCC
Figure 5.
For this configuration, connect pins 2 and 3 directly to the
positive supply rail (Vcc). The data lines are referenced to
the supply voltage. The internal TVS diode prevents
overvoltage on the supply rail. Biasing of the steering diodes
reduces their capacitance.
Option 2
Protection of four data lines with bias and power supply
isolation resistor.
8
7
6
5
1
2
3
4
I/O 1
I/O 2
I/O 3
I/O 4
VCC
10 K
Figure 6.
The SRDA05-4R2 can be isolated from the power supply
by connecting a series resistor between pins 2 and 3 and Vcc.
A 10 kW resistor is recommended for this application. This
will maintain a bias on the internal TVS and steering diodes,
reducing their capacitance.
Option 3
Protection of four data lines using the internal TVS diode
as reference.
8
7
6
5
1
2
3
4
I/O 1
I/O 2
I/O 3
I/O 4
NC
NC
Figure 7.
In applications lacking a positive supply reference or
those cases in which a fully isolated power supply is
required, the internal TVS can be used as the reference. For
these applications, pins 2 and 3 are not connected. In this
configuration, the steering diodes will conduct whenever the
voltage on the protected line exceeds the working voltage of
the TVS plus one diode drop (Vc=Vf + VTVS).
SRDA05-4R2
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ESD Protection of Power Supply Lines
When using diodes for data line protection, referencing to
a supply rail provides advantages. Biasing the diodes reduces
their capacitance and minimizes signal distortion.
Implementing this topology with discrete devices does have
disadvantages. This configuration is shown below:
VCC
D1
D2
Data Line
IESDpos
IESDneg
VF + VCC
-VF
IESDpos
IESDneg
Power
Supply
Protected
Device
Figure 8.
Looking at the figure above, it can be seen that when a
positive ESD condition occurs, diode D1 will be forward
biased while diode D2 will be forward biased when a negative
ESD condition occurs. For slower transient conditions, this
system may be approximated as follows:
For positive pulse conditions:
Vc = Vcc + VfD1
For negative pulse conditions:
Vc = -VfD2
ESD events can have rise times on the order of some
number of nanoseconds. Under these conditions, the effect of
parasitic inductance must be considered. A pictorial
representation of this is shown below.
VCC
D1
D2
Data Line
IESDpos
IESDneg
VC = VCC + Vf + (L diESD/dt)
IESDpos
IESDneg
Power
Supply
Protected
Device
VC = -Vf - (L diESD/dt)
Figure 9.
An approximation of the clamping voltage for these fast
transients would be:
For positive pulse conditions:
Vc = Vcc + Vf + (L diESD/dt)
For negative pulse conditions:
Vc = -Vf – (L diESD/dt)
As shown in the formulas, the clamping voltage (Vc) not
only depends on the Vf of the steering diodes but also on the
L diESD/dt factor. A relatively small trace inductance can result
in hundreds of volts appearing on the supply rail. This
endangers both the power supply and anything attached to
that rail. This highlights the importance of good board layout.
Taking care to minimize the effects of parasitic inductance
will provide significant benefits in transient immunity.
Even with good board layout, some disadvantages are still
present when discrete diodes are used to suppress ESD events
across datalines and the supply rail. Discrete diodes with good
transient power capability will have larger die and therefore
higher capacitance. This capacitance becomes problematic as
transmission frequencies increase. Reducing capacitance
generally requires reducing die size. These small die will have
higher forward voltage characteristics at typical ESD
transient current levels. This voltage combined with the
smaller die can result in device failure.
The ON Semiconductor SRDA05- 4R2 was developed to
overcome the disadvantages encountered when using discrete
diodes for ESD protection. This device integrates a TVS
diode within a network of steering diodes.
D1
D2
D3
D4
D5
D6
D7
D8
0
Figure 10. SRDA05-4R2 Equivalent Circuit
During an ESD condition, the ESD current will be driven
to ground through the TVS diode as shown below.
VCC
D1
D2
Data Line
IESDpos
Power
Supply
Protected
Device
Figure 11.
The resulting clamping voltage on the protected IC will
be:
Vc = VFD1 + VTVS.
The clamping voltage of the TVS diode is provided in
Figure 4 and depends on the magnitude of the ESD current.
The steering diodes are fast switching devices with unique
forward voltage and low capacitance characteristics.
SRDA05-4R2
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6
TYPICAL APPLICATIONS
UPSTREAM
USB PORT
VBUS
VBUS
VBUS VBUS
VBUS
VBUS
VBUS
VBUS
DOWNSTREAM
USB PORT
DOWNSTREAM
USB PORT
D-
D+
D-
D+
GND
GND
D-
D+
GND
USB
Controller
RT
RT
RT
RT
CT
CT
CT
CT
NUP2201MR6
SRDA05-4R2
Figure 12. ESD Protection for USB Port
Figure 13. Protection for Ethernet 10/100 (Differential Mode)
PHY
Ethernet
(10/100)
Coupling
Transformers
SRDA05-4R2
RJ45
Connector
N/C N/C
TX+
TX-
RX+
RX-
TX+
TX-
RX+
RX-
GND
VCC
SRDA05-4R2
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7
T1/E1
TRANCEIVER
RTIP
RRING
TRING
TTIP
R1
R2 R3
R4
R5
T1
T2
SRDA05-4R2
VCC
Figure 14. TI/E1 Interface Protection
SRDA05-4R2
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8
PACKAGE DIMENSIONS
SOIC-8 NB
CASE 751-07
ISSUE AH
SEATING
PLANE
1
4
58
N
J
X 45 _
K
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSION A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
6. 751-01 THRU 751-06 ARE OBSOLETE. NEW
STANDARD IS 751-07.
A
BS
D
H
C
0.10 (0.004)
DIM
A
MIN MAX MIN MAX
INCHES
4.80 5.00 0.189 0.197
MILLIMETERS
B3.80 4.00 0.150 0.157
C1.35 1.75 0.053 0.069
D0.33 0.51 0.013 0.020
G1.27 BSC 0.050 BSC
H0.10 0.25 0.004 0.010
J0.19 0.25 0.007 0.010
K0.40 1.27 0.016 0.050
M0 8 0 8
N0.25 0.50 0.010 0.020
S5.80 6.20 0.228 0.244
-X-
-Y-
G
M
Y
M
0.25 (0.010)
-Z-
Y
M
0.25 (0.010) ZSXS
M
____
1.52
0.060
7.0
0.275
0.6
0.024
1.270
0.050
4.0
0.155
ǒmm
inchesǓ
SCALE 6:1
*For additional information on our Pb-Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
SOLDERING FOOTPRINT*
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SRDA05-4R2/D
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