5
© 2011 Semtech Corp.
www.semtech.com
PRELIMINARY
PROTECTION PRODUCTS
RClamp0524J
Figure 1. Flow through Layout UsingFigure 1. Flow through Layout Using
Figure 1. Flow through Layout UsingFigure 1. Flow through Layout Using
Figure 1. Flow through Layout Using
RR
RR
R
ClamClam
ClamClam
Clam
p052p052
p052p052
p052
4J4J
4J4J
4J
HDMI Connector
3
2
1
6
5
4
9
8
7
12
11
10
HDMI Connector
3
2
1
6
5
4
9
8
7
12
11
10
GND
GNDGND
GND
1
1
Design Recommendations for HDMI Protection
Adding external ESD protection to HDMI ports can be
challenging. First ESD protection devices have an
inherent junction capacitance. However, adding even a
small amount of capacitance will cause the impedance
of the differential pair to drop. Second, large packages
and land pattern requirements cause discontinuities
that adversely affect signal integrity. The
RClamp0524J is specifically designed for protection of
high-speed interfaces such as HDMI. They present
<0.3pF capacitance between the pairs while being
rated to handle >±8kV ESD contact discharges
(>±15kV air discharge) as outlined in IEC 61000-4-2.
Each device is in a leadless SLP package that is less
than 1.1mm wide. They are designed such that the
traces flow straight through the device. The narrow
package and flow-through design reduces
discontinuities and minimizes impact on signal integrity.
This becomes even more critical as signal speeds
increase.
Pin Configuration
Figure 1 is an example of how to route the high speed
differential traces through the RClamp0524J. The
solid line represents the PCB trace. The PCB traces
are used to connect the pin pairs for each line (pin 1 to
pin 8, pin 2 to pin 7, pin 3 to pin 6, pin 4 to pin 5). For
example, line 1 enters at pin 1 and exits at Pin 8 and
the PCB trace connects pin 1 and 8 together. This is
true for lines connected at pins 2, 3, and 4 also.
Ground is connected at the center tabs. One large
ground pad should be used in lieu of two separate
pads.
TDR Measurements for HDMI
The combination of low capacitance, small package, and
flow-through design means it is possible to use these
devices to meet the HDMI impedance requirements of
100 Ohm ±15% without any PCB board modification.
Figures 3 and 4 show impedance test results for a TDR
risetime of 200ps and 100ps respectively, using a
Semtech evaluation board with 100 Ohm traces through-
out. Measurements were taken using a TDR method as
outlined in the HDMI Compliance Test Specification
(CTS). In each case, the device meets the HDMI CTS
Applications Information
SLP2710P8 Pin Configuration (Top View)
niPnoitacifitnedI
4,3,2,1seniLtupnI
8,7,6,5
seniLtuptuO
)noitcennoClanretnIoN(
DNGdnuorG
8
7
GND
65
1 2 GND 3 4
