PROTECTION PRODUCTS
1www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
RailClamp
Low Capacitance TVS Diode Array
Description Features
Circuit Diagram Schematic & PIN Configuration
Revision 08/17/2004
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 transmis-
sion lines from overvoltage caused by ESD (electrostatic
discharge), EFT (electrical fast transients), and lightning.
The unique design of the RClamp series devices incorpo-
rates four 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 RClampTM0504M has a low typical capacitance of
3pF and operates with virtually no insertion loss to
1GHz. This makes the device ideal for protection of high-
speed data lines such as USB 2.0, Firewire, and DVI
interfaces.
The RClamp0504M is designed to have ease of layout by
allowing the traces to run straight through the device.
This ease of layout coupled with the low capacitance and
clamping voltage of the RClamp0504M makes it the
superior choice for protecting four high speed lines.
The low capacitance array configuration allows the user
to protect four 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
Digital Video Interface (DVI)
10/100/1000 Ethernet
Monitors and Flat Panel Displays
Notebook Computers
High Definition Multi-Media Interface (HDMI)
USB 2.0 Power & Data Line Protection
IEEE 1394 Firewire Ports
Projection TV
ESD protection for high-speed data lines to
IEC 61000-4-2 (ESD) 15kV (air), 8kV (contact)
IEC 61000-4-5 (Lightning) 12A (8/20µs)
IEC 61000-4-4 (EFT) 40A (5/50ns)
Array of surge rated diodes with internal TVS Diode
Small package saves board space
Protects four I/O lines and one Vcc line
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)
Line 1
Vcc
NC
1
Line 3
NC Line 4
NC
GND
Line 2
NC
Pin 3
Pin 1 Pin 4 Pin 6 Pin 9
Pin 8
22004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
Absolute Maximum Rating
Electrical Characteristics (T=25oC)
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2004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
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 Capacitance vs. Reverse Voltage
0
1
2
3
4
5
01234
Reverse Voltage - VR (V)
Capacitance - Cj (pF)
I/O to GN D
f = 1MHz
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
0.00
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
42004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
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
2004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
Device Connection Options for Protection of Four
High-Speed Data Lines
The RClamp0504M TVS is designed to protect four
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.
Flow Through Layout
The RClamp0504M is designed for have ease of PCB
layout by allowing the traces to run straight through the
device. Figure 1 shows the proper way to design the PCB
board trace in order to use the flow through layout for
two line pairs. The solid line represents the PCB trace.
Note that the PCB traces are used to connect the pin
pairs for each line (pin 1 to pin 10, pin 2 to pin 9, pin 4
to pin 7, pin 5 to pin 6). For example, line 1 enters at
pin 1 and exits at Pin 10 and the PCB trace connects pin
1 and 10 together. This is true for lines 2, 3, and 4. The
negative reference (Gnd) is connected at pin 8. 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. Figure 2 shows the connection scheme to protect
both data lines and the power line by connecting 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 no positive supply reference is
available, or complete supply isolation is desired,
figure 3 shows how 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).
This ease of layout coupled with the low capacitance and
clamping voltage of the RClamp0504M makes it the
superior choice to protect two high speed line pairs.
Figure 2. Data Line and Power Supply ProtectionFigure 2. Data Line and Power Supply Protection
Figure 2. Data Line and Power Supply ProtectionFigure 2. Data Line and Power Supply Protection
Figure 2. Data Line and Power Supply Protection
Using Vcc as referenceUsing Vcc as reference
Using Vcc as referenceUsing Vcc as reference
Using Vcc as reference
Figure 3. Data Line PrFigure 3. Data Line Pr
Figure 3. Data Line PrFigure 3. Data Line Pr
Figure 3. Data Line Proo
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ection Using Intection Using Int
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ernal Ternal T
ernal TVV
VV
VSS
SS
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Diode as ReferenceDiode as Reference
Diode as ReferenceDiode as Reference
Diode as Reference
Applications Information
1Line 1
Gnd
Line 2
Line 3
Line 4
Line 1
Line 2
Line 3
Line 4
Vcc
1Line 1
Gnd
Line 2
Line 3
Line 4
Line 1
Line 2
Line 3
Line 4
NC
Line 1
Vcc
Line 2
Line 3
Line 4
Line 1
Gnd
Line 2
Line 3
Line 4
1
Figure 1. Flow through Layout for two Line PairsFigure 1. Flow through Layout for two Line Pairs
Figure 1. Flow through Layout for two Line PairsFigure 1. Flow through Layout for two Line Pairs
Figure 1. Flow through Layout for two Line Pairs
62004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
PIN Descriptions
ESD Protection With RailClamps
RailClamps are optimized for ESD protection using the
rail-to-rail topology. Along with good board layout, these
devices virtually eliminate the disadvantages of using
discrete components to implement this topology. Con-
sider the situation shown in Figure 4 where discrete
diodes or diode arrays are configured for rail-to-rail
protection on a high speed line. During positive duration
ESD events, the top diode will be forward biased when
the voltage on the protected line exceeds the reference
voltage plus the VF drop of the diode. For negative
events, the bottom diode will be biased when the voltage
exceeds the VF of the diode. At first approximation, the
clamping voltage due to the characteristics of the protec-
tion diodes is given by:
VC = VCC + VF(for positive duration pulses)
VC = -VF(for negative duration pulses)
However, for fast rise time transient events, the effects of
parasitic inductance must also be considered as shown
in Figure 5. Therefore, the actual clamping voltage seen
by the protected circuit will be:
VC = VCC + VF + LP diESD/dt (for positive duration pulses)
VC = -VF - LG diESD/dt (for negative duration pulses)
ESD current reaches a peak amplitude of 30A in 1ns for
a level 4 ESD contact discharge per IEC 61000-4-2.
Therefore, the voltage overshoot due to 1nH of series
inductance is:
V = LP diESD/dt = 1X10-9 (30 / 1X10-9) = 30V
Example:
Consider a VCC = 5V, a typical VF of 30V (at 30A) for the
steering diode and a series trace inductance of 10nH.
The clamping voltage seen by the protected IC for a
positive 8kV (30A) ESD pulse will be:
VC = 5V + 30V + (10nH X 30V/nH) = 335V
This does not take into account that the ESD current is
directed into the supply rail, potentially damaging any
components that are attached to that rail. Also note
Figure 4 - “Rail-Figure 4 - “Rail-
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(First Approximation)(First Approximation)
(First Approximation)(First Approximation)
(First Approximation)
Figure 5 - The Effects of Parasitic InductanceFigure 5 - The Effects of Parasitic Inductance
Figure 5 - The Effects of Parasitic InductanceFigure 5 - The Effects of Parasitic Inductance
Figure 5 - The Effects of Parasitic Inductance
When Using Discrete Components to ImplementWhen Using Discrete Components to Implement
When Using Discrete Components to ImplementWhen Using Discrete Components to Implement
When Using Discrete Components to Implement
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Applications Information (continued)
7
2004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
Applications Information (continued)
that it is not uncommon for the VF of discrete diodes to
exceed the damage threshold of the protected IC. This is
due to the relatively small junction area of typical dis-
crete components. It is also possible that the power
dissipation capability of the discrete diode will be ex-
ceeded, thus destroying the device.
The RailClamp is 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 inductance in
the power supply connection. During an ESD event, the
current will be directed through the integrated TVS diode
to ground. The maximum voltage seen by the protected
IC due to this path will be the clamping voltage of the
device.
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 device near the input terminals or connec-
tors 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.
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.
82004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
Figure 7 - Digital Video Interface (DVI) Protection
DVI Protection
The small geometry of a typical digital-visual interface
(DVI) graphic chip will make it more susceptible to
electrostatic discharges (ESD) and cable discharge
events (CDE). Transient protection of a DVI port can be
challenging. Digital-visual interfaces can often transmit
and receive at a rate equal to or above 1Gbps. The
high-speed data transmission requires the protection
device to have low capacitance to maintain signal
integrity and low clamping voltage to reduce stress on
the protected IC. The RClamp0504M has a low typical
insertion loss of <0.4dB at 1GHz (I/O to ground) to
ensure signal integrity and can protect the DVI interface
to the 8kV contact and 15kV air ESD per IEC 61000-4-
2 and CDE.
Figure 7 shows how to design the RClamp0504M into the
DVI circuit on a flat panel display and a PC graphic card.
The RClamp0504M is configured to provide common
mode and differential mode protection. The internal TVS
of the RClamp0504M acts as a 5 volt reference. The
power pin of the DVI circuit does not come out through
the connector and is not subjected to external ESD
pulse; therefore, pin 3 should be left unconnected.
Connecting pin 3 to Vcc of the DVI circuit may result in
damage to the chip from ESD current.
1
1
1
1
Applications Information (continued)
9
2004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
Outline Drawing - SO-8
Land Pattern - MSOP 10L
Outline Drawing -MSOP 10L
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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)
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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
102004 Semtech Corp. www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0504M
Contact Information
Semtech Corporation
Protection Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805)498-2111 FAX (805)498-3804
Marking Codes
Ordering Information
504M
XXXX
* XXXX = Date Code
** Dot indicates Pin 1
Note: Lead finish is lead-free matte tin.
RailClamp and RClamp aremarks of Semtech Corporation.
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