srda054 Semtech Corporation, srda054 Datasheet - Page 7

• Manufacturer Part Number: srda054
• Description: Srda12-4 Railclamp Low-capacitance Tvs Diode Array | Semtech
• Manufacturer: Semtech Corporation

the power supply connection. During an ESD event,
the current will be directed through the integrated TVS
diode to ground. The total clamping voltage seen by
the protected IC due to this path will be:
V
This is given in the data sheet as the rated clamping
voltage of the device. For an SRDA05-4 the typical
clamping voltage is <16V at I
internal to the RailClamp are low capacitance, fast
switching devices that are rated to handle high tran-
sient currents and maintain excellent forward voltage
characteristics.
Using the RailClamp does not negate the need for good
board layout. All other inductive paths must be consid-
ered. The connection between the positive supply and
the SRDA and from the ground plane to the SRDA
must be kept as short as possible. The path between
the SRDA and the protected line must also be mini-
mized. The protected lines should be routed directly to
the SRDA. Placement of the SRDA on the PC board is
also critical for effective ESD protection. The device
should be placed as close as possible to the input
connector. The reason for this is twofold. First,
inductance resists change in current flow. If a signifi-
cant inductance exists between the connector and the
TVS, the ESD current will be directed elsewhere (lower
resistance path) in the system. Second, the effects of
radiated emissions and transient coupling can cause
upset to other areas of the board even if there is no
direct path to the connector. By placing the TVS close
to the connector it will divert the ESD current immedi-
ately and absorb the ESD energy before it can be
coupled into nearby traces.
PROTECTION PRODUCTS
PROTECTION PRODUCTS
© 2007 Semtech Corp.
Applications Information (continued)
C
= V
F(RailClamp)
+ V
TVS
PP
=30A. The diodes
7
SRDA05-4 and SRDA12-4
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