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www.protekdevices.com

05074.R6 4/05

SMDA03LC

thru

SMDA24LCC

APPLICATION NOTE

The SMDAxxLC & SMDAxxLCC Series are TVS arrays designed to protect I/O or data lines from the damaging effects of ESD, EFT and other types

of surges. This product series provides both unidirectional and bidirectional protection, with a surge capability of 500 Watts P

waveform and ESD protection > 40kV.

UNIDIRECTIONAL COMMON-MODE CONFIGURATION(Figure 1)

The SMDAxxLC Series provides up to four (4) lines of protection in a common-mode

configuration as depicted in Figure 1.

Circuit connectivity is as follows:

✔

Line 1 is connected to Pin 5.

✔

Line 2 is connected to Pin 6.

✔

Line 3 is connected to Pin 7.

✔

Line 4 is connected to Pin 8.

✔

Pins 1-4 are connected to ground.

BIDIRECTIONAL COMMON-MODE CONFIGURATION (Figure 2)

Ideal for Ethernet applications, SMDAxxLCC Series provides up to four (4) lines of

protection in a common-mode configuration as depicted in Figure 2.

Circuit connectivity is as follows:

✔

TPIN is connected to Pin 5.

✔

TPIP is connected to Pin 6.

✔

TPON is connected to Pin 1.

✔

TPOP is connected to Pin 2.

✔

Pins 3, 4, 7 & 8 are connected to ground.

CIRCUIT BOARD LAYOUT RECOMMENDATIONS

Circuit board layout is critical for Electromagnetic

Compatibility (EMC) protection. The following

guidelines are recommended:

✔

The protection device should be placed near the

input terminals or connectors, the device will

divert the transient current immediately before it

can be coupled into the nearby traces.

✔

The path length between the TVS device and the

protected line should be minimized.

✔

All conductive loops including power and ground

loops should be minimized.

✔

The transient current return path to ground

should be kept as short as possible to reduce

parasitic inductance.

✔

Ground planes should be used whenever

possible. For multilayer PCBs, use ground vias.

Figure 1. Unidirectional Common-Mode Protection

5

6

7

8

1

2

3

4

LINE 4

LINE 3

LINE 2

LINE 1

GND PLANE

Figure 2. Bidirectional Common-Mode Protection

5

6

7

8

12

34

TPIN

TPIP

TPOP

TPON