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 2005 Semtech Corp.

www.semtech.com

PROTECTION PRODUCTS

PROTECTION PRODUCTS

LCDA15C-6

Device Connection

Multi-Mode Tranceiver Protection Example

Device Connection Options for Protection of Six High-

Speed Data Lines

The LCDA15C-6 may be configured to protect up to six

I/O lines operating between 5 and 15V. It may be used

to protect the most popular serial data interface

standard lines making it ideal for use in equipment

utilizing multi-mode transceivers. Data lines are

connected at pins 1, 2, 3, 6, 7, and 8. Pins 4 and 5

are connected to ground. For best results, these pins

should be connected directly to a ground plane on the

board. The path length should be kept as short as

possible to minimize parasitic inductance.

Multi-Mode Transceiver Protection

A typical multi-mode transceiver protection circuit is

shown. The LCDA15C-6 is used to protect I/O lines

with external connections. The LCDA15C-6 adds a

maximum loading capacitance of 15pF with a working

voltage of 15V. This allows the transceiver to safely

operate in all modes without clipping or degradation of

the signal.

With proper design and layout, the transceiver port can

be protected to >15kV (HBM per IEC 61000-4-2).

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:

Place the LCDA15C-6 near the input terminals or

connectors to restrict transient coupling.

Minimize the path length between the LCDA15C-6

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.

Applications Information

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.