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PROTECTION PRODUCTS
RClamp0504FA
Device Connection Options for Protection of Four
High-Speed Data Lines
This device is designed to protect data lines by
clamping them to a fixed reference. When the voltage
on the protected line exceeds the reference voltage
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. Pin 2
should be connected directly to a ground plane. The
path length is kept as short as possible to minimize
parasitic inductance.
The positive reference 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. In applications where the supply rail does not exit
the system, 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).
3. In applications where complete supply isolation is
desired, the internal TVS is again used as the
reference and V
CC
is connected to one of the I/O
inputs. An example of this configuration is the
protection of a SIM port. The Clock, Reset, I/O,
and VCC lines are connected at pins 1, 3, 4, and 6.
Pin 2 is connected to ground and pin 5 is not
connected.
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.
Protection of Four Data Lines and Power Supply Line
Applications Information
Protection of Four Data Lines Using Internal TVS
Diode as Reference
