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 2004 Semtech Corp.

www.semtech.com

PROTECTION PRODUCTS

PROTECTION PRODUCTS

SDC15

Device Connection for Protection of One Data Line

The SDC15 is designed to protect one data or I/O line

operating at ±12 volts. Connection options are as

follows:

Common mode protection: Pin 1 is connected to

the data line and pin 2 is connected to ground. For

best results, this pin 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. Pin 3 is not connected.

Differential protection: Pin 1 is connected to one

line and pin 2 is connected to the second line. Pin

3 is not connected.

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 SDC15 near the input terminals or

connectors to restrict transient coupling.

Minimize the path length between the SDC15 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.

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.

Device Schematic and Pin Configuration

RS-232 Transceiver Protection Example

Applications Information