RClamp0522P
RClamp0524P
PROTECTION PRODUCTS
Applications Information
ment of 100 Ohm ±15% with plenty of margin.
For signal integrity purposes, the best results will be
obtained by using the RClamp0524P to protect the high-
speed differential pairs. This is because the
device is designed such that the data lines from the
connector line up with the I/O pins of the device without
altering the trace routing. Either the RClamp0522P or
RClamp0524P may be used to protect the remaining
lines (I2C, CEC, and hot plug) depending on layout con-
straints.
Layout Guidelines for Optimum ESD Protection
Good circuit board layout is critical not only for signal
integrity, but also for effective suppression of ESD
induced transients. For optimum ESD protection, the
following guidelines are recommended:
Place the device as close to the connector as
possible. This practice restricts ESD coupling into
adjacent traces and reduces parasitic inductance.
The ESD transient return path to ground should be
kept as short as possible. Whenever possible, use
multiple micro vias connected directly from the
device ground pad to the ground plane.
Avoid running critical signals near board edges.
Protecting MDDI Ports with RClamp0524P and
RClamp0522P
The small package size and low capacitance of the
RClamp0522P and RClamp0524P make them ideal
for high-speed lines in portable applications. One such
application is the protection of MDDI ports in cellular
phones. MDDI is a serial data interface operating
at 480Mb/s per line pair. The lines are scalable for
increased speed and display resolution. A MDDI
port protection example is shown in Figure 4. The
RClamp0524P is used to protect two differential line
pairs while an RClamp0522P is used to protect the
MDDI strobe lines. Note that devices are used on both
the main board and LCD side of the MDDI port. Devices
on the main board are needed to protect the MDDI
controller in the Baseband processor. Devices on the
LCD board are needed to protect MDDI controller in
the LCD module. A TVS such as the uClamp0501P is
used to protect the MDDI power line. The protection
devices should be placed close to the connector of each
board. Traces are routed directly through each device,
minimizing parasitic inductance. Connections to the
ground plane should be made with multiple micro vias
when possible.
2006 Semtech Corp.
7
PRELIMINARY
B
A
X-axis
Y-axis
A
1.905
101.0
B
2.081
107.0
(nsec)
(Ohm)
Figure 2 - TDR Measurement with 200ps risetime us-
ing Semtech Evaluation Board
B
A
X-axis
Y-axis
A
1.80
96
B
2.076
108.0
(nsec)
(Ohm)
Figure 3 - TDR Measurement with 100ps risetime us-
ing Semtech Evaluation Board
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SEMTECH [ SEMTECH CORPORATION ]
