NUP2105L

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6

TVS Diode Protection Circuit

TVS diodes provide protection to a transceiver by

clamping a surge voltage to a safe level. TVS diodes have

high impedance below and low impedance above their

breakdown voltage. A TVS Zener diode has its junction

optimized to absorb the high peak energy of a transient

event, while a standard Zener diode is designed and

specified to clamp a steady state voltage.

Figure 7 provides an example of a dual bidirectional

TVS diode array that can be used for protection with the

high−speed CAN network. The bidirectional array is created

from four identical Zener TVS diodes. The clamping

voltage of the composite device is equal to the breakdown

voltage of the diode that is reversed biased, plus the diode

drop of the second diode that is forwarded biased.

Figure 7. High−Speed and Fault Tolerant CAN TVS

Protection Circuit

CAN

Transceiver

CAN_H

CAN_L

NUP2105L

CAN Bus