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RCLAMP0554S.TCT

P1-P3P4-P6P7-P9
4© 2011 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
RClamp0554S
Insertion Loss S21 - Any I/O to GND
Applications Information
1
2
3
4
5
START
.
030 MHz
3
STOP 000
.
000 000 MHz
CH1 S21 LOG 6 dB / REF 0 dB
1: -1.0964 dB
800 MHz
2: -1.2545 dB
900 MHz
3: -6.7229 dB
1.8 GHz
4: -16.4457 dB
2.5 GHz
0 dB
-6 dB
-12 dB
-18 dB
-24 dB
-30 dB
-36 dB
1
GHz
100
MHz
3
GHz
10
MHz
1
MHz
-42 dB
-48 dB
Insertion Loss S21 - I/O to I/O
1
2
3
4
5
START
.
030 MHz
3
STOP 000
.
000 000 MHz
CH1 S21 LOG 6 dB / REF 0 dB
1: -0.47220 dB
800 MHz
2: -0.5278 dB
900 MHz
3: -2.6811 dB
1.8 GHz
4: -9.2328 dB
2.5 GHz
0 dB
-6 dB
-12 dB
-18 dB
-24 dB
-30 dB
-36 dB
1
GHz
100
MHz
3
GHz
10
MHz
1
MHz
-42 dB
-48 dB
ESD Clamping - Between any I/O and GND
(-8kV Contact per IEC 61000-4-2)
Note: Data is taken with a 10x attenuator
ESD Clamping - Between any I/O and GND
(+8kV Contact per IEC 61000-4-2)
Note: Data is taken with a 10x attenuator
5© 2011 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
RClamp0554S
Device Connection Options for Protection of Four
High-Speed Data Lines
The RClamp0554S 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 V
F
) the
steering diodes are forward biased, conducting the
transient current away from the sensitive circuitry.
Data lines are connected at pins 1, 3, 4 and 6. The
negative reference (REF1) is connected at pin 2. 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 (REF2) is connected at pin 5.
The options for connecting the positive reference are
as follows:
1. To protect data lines and the power line, connect
pin 5 directly to the positive supply rail (V
CC
). In this
configuration the data lines are referenced to the
supply voltage. The internal TVS diode prevents
over-voltage on the supply rail.
2. The RClamp0554S can be isolated from the power
supply by adding a series resistor between pin 5
and V
CC
. A value of 100kΩ is recommended. The
internal TVS and steering diodes remain biased,
providing the advantage of lower capacitance.
3. In applications where no positive supply reference
is available, or complete supply isolation is desired,
the internal TVS may be used as the reference. In
this case, pin 5 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).
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.
Consider the situation shown in Figure 1 where dis-
crete 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
Data Line and Power Supply Protection Using Vcc as
reference
Data Line Protection with Bias and Power Supply
Isolation Resistor
Data Line Protection Using Internal TVS Diode as
Reference
Applications Information
6© 2011 Semtech Corp.
www.semtech.com
PROTECTION PRODUCTS
RClamp0554S
PIN Descriptions
the reference voltage plus the V
F
drop of the diode.
For negative events, the bottom diode will be biased
when the voltage exceeds the V
F
of the diode. At first
approximation, the clamping voltage due to the charac-
teristics of the protection diodes is given by:
V
C
= V
CC
+ V
F
(for positive duration pulses)
V
C
= -V
F
(for negative duration pulses)
However, for fast rise time transient events, the
effects of parasitic inductance must also be consid-
ered as shown in Figure 2. Therefore, the actual
clamping voltage seen by the protected circuit will be:
V
C
= V
CC
+ V
F
+ L
P
di
ESD
/dt (for positive duration pulses)
V
C
= -V
F
- L
G
di
ESD
/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 = L
P
di
ESD
/dt = 1X10
-9
(30 / 1X10
-9
) = 30V
Example:
Consider a V
CC
= 5V, a typical V
F
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:
V
C
= 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
that it is not uncommon for the V
F
of discrete diodes to
exceed the damage threshold of the protected IC. This
is due to the relatively small junction area of typical
discrete components. It is also possible that the
power dissipation capability of the discrete diode will
be exceeded, 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
Figure 1 - “Rail-Figure 1 - “Rail-
Figure 1 - “Rail-Figure 1 - “Rail-
Figure 1 - “Rail-
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Figure 2 - The Effects of Parasitic InductanceFigure 2 - The Effects of Parasitic Inductance
Figure 2 - The Effects of Parasitic InductanceFigure 2 - The Effects of Parasitic Inductance
Figure 2 - 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)
P1-P3P4-P6P7-P9

RCLAMP0554S.TCT

Mfr. #:
Buy RCLAMP0554S.TCT
Manufacturer:
Semtech
Description:
TVS Diodes / ESD Suppressors 4-LINE 5V 5PF 25A
Lifecycle:
New from this manufacturer.
Delivery:
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