SD05 and SD12
Device Connection Options
The SDxx TVS diodes are designed to protect one data,
I/O, or power supply line. The device is designed to
replace multi-layer varistors (MLVs) in portable
applications. It is easily implemented on existing 0805
MLV pads and is only slightly larger than 0603 MLV
pads. The device is unidirectional and may be used on
lines where the signal polarity is above ground. The
cathode band should be placed towards the line that is
to be protected.
Circuit Board Layout Recommendations for Suppres-
sion of ESD.
Good circuit board layout is critical for the suppression
of fast rise-time transients such as ESD. The following
guidelines are recommended (Refer to application note
SI99-01 for more detailed information):
z Place the TVS near the input terminals or
connectors to restrict transient coupling.
z Minimize the path length between the TVS and
the protected line.
z The ESD transient return path to ground should
be kept as short as possible.
z Place a TVS and decoupling capacitor between
power and ground of components that may be
vulnerable to electrostatic discharges to the
z Minimize all conductive loops including power
and ground loops.
z Use multilayer boards when possible.
z Minimize interconnecting line lengths
z Never run critical signals near board edges.
z Fill unused portions of the PCB with ground
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.
2004 Semtech Corp.
Device Schematic and Pin Configuration
Size Comparison to 0805 MLV
Note: Nominal dimensions in inches
Component Placement Comparison
0805 MLV on
0805 Solder Pad
SOD-323 on 0805
SOD-323 on Recommended
(SOD-323) Solder Pad