ESD/CDE Protection

Application Brief
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ESD/CDE Protection
For High Definition Multimedia Interface (HDMI)
Breakthrough Protection Device for HDMI 1.3 with ultra low
capacitance of 0.3pF
High Definition Multimedia Interface (HDMI) is an
uncompressed, all-digital audio/video interface that
provides a high-speed link between audio/video
source devices, such as DVD players, and sink
devices, such as HDTV. In order to receive HDMI
certification, both sink and source devices need to
comply with respective test requirements set forth
by the HDMI Compliance Test Specification (CTS).
HDMI 1.3 is the current specification, which
supersedes its predecessor, HDMI 1.2, by doubling
the bandwidth and increasing the maximum data
rate from 1.65Gbps per differential pair to 3.4Gbps.
With the increase in data speed, signal integrity
maintenance is crucial in order to meet HDMI eye
pattern and TDR requirements. This is not a trivial
task since the differential impedance can be easily
affected by the introduction of even a small amount
of capacitance or inductance. In addition, the
externally accessible HDMI ports are becoming
increasingly more susceptible to transient threats.
The threats can come from any charged entity;
for example, from either a user’s direct touch or
from hot plugging a charged cable. The internal
on-chip ESD structures do not provide sufficient
protection needed to keep the sensitive HDMI
chip from becoming damaged. To protect against
the over-voltage stress induced by users and ESD
testing, external protection is required. With this
added concern, HDMI designers need to meet
the ESD immunity requirement of IEC 61000-4-2
while maintaining signal integrity and impedance
requirements per the HDMI CTS.
HDMI has been a dramatic success with
more than 60 million HDMI-equipped
devices shipped in 2006. In June 2006,
the new HDMI 1.3 standard was introduced
for improved color depth and audio output.
HDMI 1.3 doubles the data rate of HDMI
signals to 3.4Gbps per differential pair.
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RClamp®0524P for HDMI 1.3
With a maximum differential capacitance value of 0.4pF,
Semtech’s RClamp0524P can be used directly on 2
pairs of 100 Ohm differential impedance signal lines
regardless of the board type, number of layers, thickness,
or board material. To further facilitate the high-speed
design, RClamp0524P is housed in a small leadless
package with 0.5mm pitch, flow-through layout. The
package design helps to reduce discontinuities and
increase common noise rejection through tight-pitch
coupling. Figure 1 (see below) shows an example of
high-speed differential trace routing with Semtech’s
RClamp0524P.
In addition to streamlining high-speed signal line
design and maintaining the impedance requirement,
RClamp0524P is designed specifically to provide ESD
protection to Level 4, IEC 61000-4-2 ESD standard
(±8kV contact ESD and ±15kV air ESD) and, at the
same time, to provide superior clamping voltage performance. The RClamp0524P’s low clamping voltage
reduces the over-voltage stress on the HDMI chip, which
increases the overall HDMI system’s reliability.
Test Results and Recommendations
The low capacitance, clamping voltage, and operating
voltage of the Semtech’s RClamp0524P, coupled with
its innovative package design, make it a superior
protection device for HDMI applications. Semtech has
produced 2-layer and 4-layer HDMI evaluation boards,
which are available for customers to evaluate the
RClamp0524P’s TDR and eye pattern performance.
Figure 2 and Figure 3, respectively, show the TDR
results on 4-layer and 2-layer HDMI evaluation boards.
Both results show that the TDR has met, and is well
within, the HDMI CTS requirement (100 Ohm ±15%
for differential impedance).
1
8
2
7
GND
GND
3
6
4
5
1
8
2
7
GND
GND
3
6
4
5
Figure 1: Flow-through layout of Semtech’s RClamp0524P for HDMI Applications
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RClamp®0524P for HDMI 1.3
Figure 4: RClamp0524P HDMI Eye Pattern Result
(1.48Gbps)
Figure 2: RClamp0524P 4-Layer HDMI TDR Result
Figure 5: RClamp0524P HDMI Eye Pattern Result
(2.25Gbps)
Conclusion
Figure 3: RClamp0524P 2-Layer HDMI TDR Result
Designers of HDMI systems are faced with the difficult
challenge of providing reliable ESD protection while
meeting the signal integrity requirement per HDMI
CTS. Proper selection of added external protection
devices is imperative. The chosen protection device
must exhibit very low capacitance while keeping the
ESD clamping voltage at a minimum to maintain the
quality and reliability of the protected IC. This will
ensure that the HDMI chip will not experience
catastrophic or latent failure during a transient threat.
With an ultra-low capacitance value and superior ESD
protection capability, Semtech’s RClamp0524P
will ensure the compliance of an HDMI application to
both HDMI 1.3 CTS and ESD requirements without the
need for any further board or device compensation.
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Application Brief
Electrical Characteristics (T=25°)
Parameter
Symbol
Conditions
Minimum
Typical
Maximum
Units
Reverse Stand-Off Voltage
VRWM
Any I/O pin to ground
5
V
Reverse Breakdown Voltage
VBR
It=1mA
Any I/O pin to ground
Reverse Leakage Current
IR
VRWM=5V, T=25°C
Any I/O pin to ground
1
µA
Clamping Voltage
Vc
Ipp=1A, tp=8/20µs
Any I/O pin to ground
15
V
Junction Capacitance
Cj
VR=OV, f=1MHZ
Between I/O pins
0.4
pF
Junction Capacitance
Cj
VR=OV, f=1MHz
Any I/O pin to ground
0.8
pF
6
V
0.30
Outline Drawing – SLP2510P8
DIMENSIONS
INCHES
DIM
MIN NOM MAX
A
.020 .023 .026
A1 0.00 .001 .002
A2
(.005)
b
.006 .008 .010
b1 .014 .016 .018
D .094 .098 .102
E
.035 .039 .043
e
.020 BSC
L
.012 .015 .017
N
8
aaa
.003
bbb
.004
MILLIMETERS
MIN NOM MAX
.050 0.58 0.65
0.00 0.03 0.05
(0.13)
0.15 0.20 0.25
0.35 0.40 0.45
2.40 2.50 2.60
0.90 1.00 1.10
0.50 BSC
0.30 0.38 0.425
8
0.08
0.10
Notes:
1. Controlling dimensions are in millimeters
(Angles in degrees).
Land Pattern – SLP2510P8
DIM
C
G
P
P1
X
X1
Y
Y1
Z
DIMENSIONS
INCHES
MILLIMETERS
(.034)
(0.875)
.008
0.20
0.20
0.50
.039
1.00
.008
0.20
.016
0.40
0.675
.027
(1.55)
(.061)
1.55
.061
Notes:
1. Controlling dimensions are in millimeters
(Angles in degrees).
2. This land pattern is for reference
purposes only.
3. Consult your manufacturing group to
ensure your company’s manufacturing
guidelines are met.
Visit our website to locate the most current product specifications, datasheets and contact information for your local Semtech Field Applications Engineer.
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HDMI-APPAG-0707