TLE7259G_07 Datasheet, PDF (12/27 Pages) Infineon Technologies AG – LIN Transceiver

TLE7259G
Functional Description
4.10
TxD time out function
If the TxD signal is dominant for a time t > t_timeout the TxD time-out function deactivates the transmission of the LIN
signal to the bus. This is realized to prevent the bus from being permanently blocked by a permanent “Low” signal
on the TxD pin due to an error.
The transmission is released again, after a rising edge at TxD has been detected.
4.11
Over temperature protection
The TLE7259G has an integrated over temperature sensor, to protect the device against thermal overstress. In
case of an over temperature event, the temperature sensor will disable the output stage. An over temperature
event will not cause any mode change nor will it be signaled by either the RxD pin or the TxD pin. When the
junction temperature falls below the thermal shut down level T_J < T_jSD, the output stage is re-enabled and data
communication can start again. A10°C hysteresis avoids toggling during the temperature shut down.
4.12
3.3 V and 5 V Logic Capability
The TLE7259G can be used for 3.3 V and 5 V micro controllers. The inputs (TxD, EN) take the reference voltage
from the connected micro controller pins. The RxD output must have an external pull-up resistor to the micro
controller supply, to define the output voltage level.
4.13
BUS Short to GND Feature
The TLE7259G has a feature implemented to protect the battery from running out of charge in the case the LIN
bus is shorted to GND.
In this failure case a normal master termination, a 1 kΩ resistor and a diode connected between the Bus pin and
the power supply V_S, would cause a constant current between V_S and GND, even in sleep mode. The resulting
resistance between V_S and GND of this LIN bus short to GND is lower than 1 kΩ. To avoid this current during a
generator off state, like in a parked car, the TLE7259G has a Bus Short to GND feature implemented. This feature
is only applicable, if the master termination is connected to the INH pin, instead of the V_S power supply (see
Figure 11 and Figure 12). In Sleep mode the INH pin is switched of and no currently can flow between V_S and
GND. The internal 30 kΩ bus termination is also switched off (see Figure 1 and Table 2) to minimize the discharge
current.
4.14
LIN Specifications 1.2, 1.3, 2.0 and 2.1
The device fulfills the Physical Layer Specification of LIN 1.2, 1.3, 2.0 and 2.1.
The differences between LIN specification 1.2 and 1.3 is mainly the physical layer specification. The reason was
to improve the compatibility between the nodes.
The LIN specification 2.0 is a super set of the 1.3 version. The 2.0 version offers new features. However, it is
possible to use the LIN 1.3 slave node in a 2.0 node cluster, as long as the new features are not used. Vice versa
it is possible to use a LIN 2.0 node in the 1.3 cluster without using the new features.
In terms of the physical layer the LIN 2.1 Specification doesn’t include any changes and is fully compliant to the
LIN Specification 2.0.
LIN 2.1 is the latest version of the LIN specification, released in December 2006.
Data Sheet
12
Rev 2.1, 2007-04-27