TLE7257 Datasheet, PDF (6/31 Pages) Infineon Technologies AG – LIN Transceiver

TLE7257
Functional Description
4
Functional Description
The LIN interface is a single wire, bi-directional bus, used for in-vehicle networks. The TLE7257 LIN transceiver
is the interface between the microcontroller and the physical LIN Bus (see Figure 16). Data from the
microcontroller is driven to the LIN bus via the TxD input of the TLE7257. The transmit data stream on the TxD
input is converted to a LIN bus signal with optimized slew rates in order to minimize the electromagnetic emission
level of the LIN network. The RxD output reads back the information from the LIN bus to the microcontroller. The
receiver has an integrated filter network to suppress noise from the LIN bus and to increase the electromagnetic
immunity level of the transceiver.
The LIN specification defines two valid bus states (see Figure 3):
• “Dominant” state with the LIN bus voltage level near GND.
• “Recessive” state with the LIN bus voltage pulled up to the supply voltage V_S through the bus termination.
By setting the TxD input of the TLE7257 to a logical “low” signal, the transceiver generates a “dominant” level on
the BUS interface pin. The receiver reads back the signal on the LIN bus and indicates the “dominant” LIN bus
signal with a logical “low” level on the RxD output to the microcontroller. By setting the TxD input to logical “high”,
the transceiver sets the LIN interface pin to the “recessive” level. At the same time the “recessive” level on the LIN
bus is indicated by a logical “high” level on the RxD output.
Every LIN network consists of a master node and one or more slave nodes. To configure the TLE7257 for master
node applications, a termination resistor of 1 kΩ and a diode must be connected between the LIN bus and the
power supply V_S (see Figure 16).
V_CC
TxD
V_S
BUS
Recessive
V_{th_DOM}
V_CC
RxD
Figure 3 LIN bus signals
Dominant
t
Recessive
V_{th_REC}
t
t
TLE7257_LIN_COMMUNICATION
Data Sheet
6
Rev. 1.0, 2013-10-16