1www.semtech.com
PROTECTION PRODUCTS - RailClamp
RClamp0508M
RailClamp
Low Capacitance TVS Diode Array
Description Features
Circuit Diagram PIN Configuration
Revision 01/18/2008
RailClamps are surge rated diode arrays designed to
protect high speed data interfaces. The RClamp series
has been specifically designed to protect sensitive
components which are connected to data and trans-
mission lines from overvoltage caused by ESD (electro-
static discharge), CDE (cable discharge events), EFT
(electrical fast transients), and lightning.
The unique design of these devices incorporates 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 components.
The RClampTM0508M has a low typical capacitance of
3pF and may be used on lines operating up to 1GHz.
This makes the device ideal for protection of high-
speed data lines such as USB 2.0, Firewire, DVI, and
gigabit Ethernet interfaces.
The low capacitance array configuration allows the user
to protect eight high-speed data or transmission lines.
The low inductance construction minimizes voltage
overshoot during high current surges. They may be
used to meet the ESD immunity requirements of IEC
61000-4-2, Level 4 (15kV air, 8kV contact discharge).
Applications
Mechanical Characteristics
USB 2.0 Power & Data Line Protection
Video Graphics Cards
Monitors and Flat Panel Displays
Digital Video Interface (DVI)
High Definition Multi-Media Interface (HDMI)
10/100/1000 Ethernet
ATM Interfaces
IEEE 1394 Firewire Ports
ESD 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) 12A (8/20µs)
Array of surge rated diodes with internal TVS
Small package saves board space
Protects eight I/O lines operating up to 1GHz1GHz
1GHz1GHz
1GHz
Low capacitance: 3pF typical
Low clamping voltage
Low operating voltage: 5.0V
Solid-state silicon-avalanche technology
JEDEC MSOP-10L package
Molding compound flammability rating: UL 94V-0
Marking : Marking code and date code
Packaging : Tape and Reel per EIA 481
Lead Finish: Matte Tin
MSOP-10L (Top View)
3
124 5
6
78910
Line 1
GND
Line 2
1
Line 3
Line 4
Line 5
Line 6
Vcc
Line 7
Line 8
2 2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
Absolute Maximum Rating
Electrical Characteristics (T=25oC)
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2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
Typical Characteristics
Non-Repetitive Peak Pulse Power vs. Pulse Time Power Derating Curve
0
10
20
30
40
50
60
70
80
90
100
110
0 25 50 75 100 125 150
Ambient Temperature - TA (oC)
% of Rated Power or IPP
Clamping Voltage vs. Peak Pulse CurrentPulse Waveform
Forward Voltage vs. Forward Current Normalized Capacitance vs. Reverse Voltage
0.00
5.00
10.00
15.00
20.00
25.00
30.00
0.00 2.00 4.00 6.00 8.00 10.00 12.00
Peak Pulse Current - Ipp (A)
Clamping Voltage -Vc (V)
Waveform
Parameters:
tr = 8µs
td = 20µs
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0.00 2.00 4.00 6.00 8.00 10.00 12.00
Forward Current - IF (A)
Forward Voltage -VF (V)
Waveform
Parameters:
tr = 8µs
td = 20µs
0.01
0.1
1
10
0.1 1 10 100 1000
Pulse Duration - tp (µs)
Peak Pulse Power - PPP (kW)
0
10
20
30
40
50
60
70
80
90
100
110
0 5 10 15 20 25 30
Time (µs)
Percent of I PP
e-t
td = IPP/2
Waveform
Parameters:
tr = 8µs
td = 20µs
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
012345
Reverse Voltage - VR (V)
CJ(VR) / CJ(VR=0)
f = 1 MHz
4 2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
CH1 S21 LOG 20 dB/ REF 0 dB
START .030 000 MHz STOP 3 000.000 000 MHz
Insertion Loss S21 Analog Cross Talk
Typical Characteristics (Con’t)
3 dB/
CH1 S21 LOG REF 0 dB
START .030 000 MHz STOP 3 000.000 000 MHz
5
2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
Applications Information
Device Connection Options for Protection of Eight
High-Speed Data Lines
This device is designed to protect eight data lines from
transient over-voltages by clamping them to a fixed
reference. When the voltage on the protected line
exceeds the reference voltage (plus diode VF) 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, 7, 8, 9,
and 10. The negative reference is connected at pin 6.
This pin 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 pin 3. The
options for connecting the positive reference are as
follows:
1. To protect data lines and the power line, connect
pin 3 directly to the positive supply rail (VCC). In this
configuration the data lines are referenced to the
supply voltage. The internal TVS diode prevents
over-voltage on the supply rail.
2. In applications where the supply rail does not exit
the system, the internal TVS may be used as the
reference. In this case, pin 3 is not connected.
The steering diodes will begin to conduct when the
voltage on the protected line exceeds the working
voltage of the TVS (plus one diode drop).
Universal Serial Bus ESD Protection
The RClamp0508M may be used to protect USB 2.0
ports on monitors, computers, peripherals or portable
systems. Each device will protect up to four USB ports.
When the voltage on the data lines exceed the bus
voltage (plus one diode drop), the internal rectifiers are
forward biased conducting the transient current away
from the protected controller chip. The TVS diode
directs the surge to ground. The TVS diode also acts
to suppress ESD strikes directly on the voltage bus.
Thus, both power and data pins are protected with a
single device.
Schematic
Pin Configuration
3
124 5
6
78910
Line 1
GND
Line 2
1
Line 3
Line 4
Line 5
Line 6
Vcc
Line 7
Line 8
6 2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
Applications Information
ESD Protection With RailClamps
RailClamps are optimized for ESD protection using the
rail-to-rail topology. They are designed to overcome the
inherent disadvantages of using discrete signal diodes
for ESD suppression. The RailClamp’s integrated TVS
diode helps to mitigate the effects of parasitic induc-
tance in the power supply connection. During an ESD
event, the current will be directed through the inte-
grated TVS diode to ground. The maximum voltage
seen by the protected IC due to this path will be the
clamping voltage of the device. The line loading capaci-
tance is minimized by using low capacitance steering
diodes. The steering diodes are scaled to handle high
current ESD events without damage or degradation.
The end result is a highly reliable, integrated solution
that eliminates the guess work associated with using
discrete components.
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.
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2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
Applications Information - SPICE Model
RClamp0508M Spice Model
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8 2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
Outline Drawing - SO-8
Land Pattern - MSOP 10L
Outline Drawing - MSOP 10L
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A
B
C
D
PLANE
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SEATING
INDICATOR
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2X N/2 TIPS
PIN 1
2X E/2
A1
A
A2
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SIDE VIEW
SEE DETAIL A
E1
12
N
DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS
3.
OR GATE BURRS.
DATUMS AND TO BE DETERMINED AT DATUM PLANE
CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
-B-
NOTES:
1.
2. -A- -H-
REFERENCE JEDEC STD MO-187, VARIATION BA.4.
H
DETAIL
0.25
PLANE
GAGE
01
c
(L1)
L
A
0°
.010
.004
-
.016
.003
.024
(.037)
-
.000
.030
-
-
-
-
0.25
0.10
8° 0° -8°
0.60
(.95)
.032
.009
0.40
0.08
.043
.006
.037 0.75
0.00
-
0.80
0.23
-
0.95
1.10
0.15
-
-
-
.193 BSC
.020 BSC
10
.003
.114
.114
.118
.118
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10
0.08
3.00
3.00
4.90 BSC
0.50 BSC
.122
.122
2.90
2.90
.011 0.17
3.10
3.10
0.27
-
DIM
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A1
e
bbb
aaa
01
L1
N
L
D
E1
E
A2
b
c
A
MILLIMETERS
NOM
INCHES
DIMENSIONS
MIN NOM MAX MIN MAX
E
THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
NOTES:
1.
P
(C)
X
Z
G
Y
.063
.224
.011
.020
.098
(.161)
5.70
1.60
0.30
0.50
2.50
(4.10)
MILLIMETERS
DIMENSIONS
DIM INCHES
Y
Z
G
P
X
C
9
2008 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
RClamp0508M
Contact Information
Semtech Corporation
Protection Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805)498-2111 FAX (805)498-3804
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Marking Codes
Ordering Information
508M
XXXX
* XXXX = Date Code
** Dot indicates Pin 1
RailClamp and RClamp are marks of Semtech Corporation
Note: Lead finish is lead free matte tin
