uclamp3311p Semtech Corporation, uclamp3311p Datasheet - Page 4

• Manufacturer Part Number: uclamp3311p
• Description: Uclamp3311p Low Voltage ?clamp? For Esd And Cde Protection
• Manufacturer: Semtech Corporation

Device Connection Options
The μClamp3311P is designed to protect one data line
operating up to 3.3 volts. It will present a high
impedance to the protected line up to 3.3 volts. It will
“turn on” when the line voltage exceeds 3.5 volts. The
device is bidirectional and may be used on lines where
the signal polarity is above and below ground. These
devices are not recommended for use on dc power supply
lines due to their snap-back voltage characteristic.
EPD TVS Characteristics
These devices are constructed using Semtech’s
proprietary EPD technology. The structure of the EPD
TVS is vastly different from the traditional pn-junction
devices. At voltages below 5V, high leakage current
and junction capacitance render conventional ava-
lanche technology impractical for most applications.
However, by utilizing the EPD technology, these devices
can effectively operate at 3.3V while maintaining
excellent electrical characteristics.
The EPD TVS employs a complex nppn structure in
contrast to the pn structure normally found in tradi-
tional silicon-avalanche TVS diodes. The EPD mecha-
nism is achieved by engineering the center region of
the device such that the reverse biased junction does
not avalanche, but will “punch-through” to a conduct-
ing state. This structure results in a device with supe-
rior DC electrical parameters at low voltages while
maintaining the capability to absorb high transient
currents.
Circuit Board Layout Recommendations for Suppres-
sion of ESD.
Good circuit board layout is critical for the suppression
of ESD induced transients. The following guidelines are
recommended:
PROTECTION PRODUCTS
© 2007 Semtech Corp.
Applications Information
Place the TVS near the input terminals or connec-
tors to restrict transient coupling.
Minimize the path length between the TVS and the
protected line.
Minimize all conductive loops including power and
ground loops.
The ESD transient return path to ground should be
kept as short as possible.
Never run critical signals near board edges.
Use ground planes whenever possible.
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Device Schematic & Pin Configuration
EPD TVS IV Characteristic Curve
V
F
I
I
I
I
SB
PT
PP
R
I
F
uClamp3311P
V
RWM
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V
SB
V
PT
V
C