PLC496_07 Datasheet, PDF (4/5 Pages) Protek Devices – ULTRA LOW CAPACITANCE TVS ARRAY

PLC496
APPLICATION NOTE
The PLC496 is an ultra low capacitance, bidirectional array that is designed to protect I/O or high speed data lines from the damaging effects of ESD
or EFT. This product has a surge capability of 500 Watts P_PP per line for an 8/20µs waveshape and offers ESD protection > 40kV.
DIFFERENTIAL-MODE CONFIGURATION (Figure 1)
The PLC496 is designed to protect one bidirectional line where the normal signal
voltage is both positive and negative. Figure 1 shows a typical differential-mode
line to line) I/O port protection circuit application.
Circuit connectivity is as follows:
✔ Pins 1, 4 5 and 8 are connected to the data lines
✔ Pins 2, 3, 7 and 6 are not connected.
COMMON-MODE CONFIGURATION (Figure 2)
The PLC496 can provide protection for sensor circuit applications. Figure 2, is a
typical common-mode (line to ground) sensor circuit application.
Circuit connectivity is as follows:
✔ Pins 1 and 8 connected to the dataline
✔ Pins 4 and 5 connected to ground
✔ Pins 2, 3, 6, and 7 are not connected
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. Typical Differential Mode I/O Port Protection
LINE 1 IN
1
LINE 1
OUT
8
NC ₂
7 NC
NC 3
6 NC
4
5
LINE 2 IN
LINE 2
OUT
Figure 2. Typical Common Mode Sensor Protection Circuit
SENSOR
1
NC 2
NC 3
4
8
7 NC
6 NC
CIRCUITRY
5
1
8
NC ₂
7 ^NC
NC 3
6 NC
4
5
05109.R7 2/07
4
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