DocID024014 Rev 2

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AN4218

Application circuits

System reliability

The ESD-diodes inside of the microcontroller are designed for short discharge pulses only,

not to sustain a constant current over time. Therefore the maximum continuous voltage drop

over them is specified in the absolute maximum ratings to be not higher than 0.3 V. In this

case only a very limited current is flowing through them.

A continuous current may lead to a degrading effect on these diodes over time.

3.2.3

Physical layer

Physical layer interfaces such as CAN-transceiver and LIN-transceivers may not have a

reverse protection from the physical layer to its power supply, which may be connected to

the bus this may lead to residual voltages while the microcontroller is not supplied.

CAN-transceiver without reverse protection show the backward current through an

network the CAN-bus is expected to be always supplied even while the microcontroller is

not.

Figure 23. CAN-transceiver without reverse protection