TLE7257 Datasheet, PDF (16/31 Pages) Infineon Technologies AG – LIN Transceiver

TLE7257
Functional Description
4.9
TxD Time-out
The TxD time-out feature protects the LIN bus against permanent blocking in case the logical signal on the TxD
input is continuously “low”, caused by e.g. a malfunctioning microcontroller or a short circuit on the printed circuit
board. In Normal Operation mode, a logical “low” signal on the TxD input for the time t_TxD disables the output stage
of the transmitter (see Figure 13). The receiver will remain active and the data on the bus are still monitored on
the RxD output.
The TLE7257 will release the output stage after a TxD time-out event first when detecting a logical “high” signal
on the TxD input for the time t_to,rec.
TxD time-out due to e.g. microcontroller error
t_TxD
Normal communication
Recovery of the microcontroller error
Release after TxD time-out
t_to,rec
Normal communication
TxD
t
V_BUS
Figure 13 TxD time-out
t
TLE7257_TXD_TIMEOUT
4.10
3.3 V and 5 V Logic Capability
The TLE7257 can be used for 3.3 V and 5 V microcontrollers. The logic inputs and the outputs are capable to
operate with both voltage levels. The RxD output needs an external pull-up resistor to the microcontroller supply
to define the voltage level (see Chapter 7.6 “RxD Pull-up Resistor” on Page 26 and Figure 16).
4.11
Short Circuit
The BUS pin of TLE7257 can withstand short circuits to either GND or to the V_S power supply. The integrated over-
temperature protection may disable the transmitter in case of a permanent short circuit on the bus pin is causing
the overheating.
Data Sheet
16
Rev. 1.0, 2013-10-16