Data Sheet

16

Rev. 1.1

2018-10-15

TLE8457C / TLE8457D

LIN Transceiver with integrated voltage regulator

Functional description

4.4.1

TxD time-out

The TxD time-out feature protects the LIN bus against permanent blocking in the case where the logical signal

on the TxD input is continuously “low”, caused by a malfunctioning microcontroller or a short circuit on the

printed circuit board for example. In normal operation mode, a logic “low” signal on the TxD input for time t >

on the BUS is still monitored on the RxD output.

The TLE8457C / TLE8457D will release the output stage after a TxD time-out event first when detecting a logic

Figure 13

TxD time-out

4.4.2

Short-circuit

integrated overtemperature protection may disable the transmitter if a permanent short circuit on the BUS

pin causes the TLE8457C / TLE8457D to overheat.

4.5

Overtemperature protection

The TLE8457C / TLE8457D has two independent overtemperature detectors for protecting the device against

thermal overstress, namely on the voltage regulator pass element and on the LIN bus transmitter. In the case

nor mode change, will occur. After the LIN transmitter overtemperature recovery, the TxD input requires a

logic “high” signal before restarting data transmission.

If an overtemperature event is detected on the voltage regulator, it will be disabled and the NRST output will

be set “low”. During the overtemperature condition no functionality of the TLE8457C / TLE8457D is available.

Note:

The overtemperature detection of the LIN transmitter and the voltage regulator are working

independently. Therefore either only the LIN transmitter or only the voltage regulator or both can be

switched off, depending on the circumstance. An example of only LIN transmitter overtemperature

could be bus short-circuit or severe electromagnetical injection.

TLE8457_TXD_TIMEOUT_A

t

TxD

TxD time-out due to e.g. microcontroller error

Release after TxD time-out

Recovery of the microcontroller error

t

Normal communication

Normal communication