TLE7257

Functional Description

Data Sheet

6

Rev. 1.0, 2013-10-16

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

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

Figure 3

LIN bus signals

TLE7257_LIN_COMMUNICATION

t

TxD

V

CC

BUS

V

S

t

t

RxD

V

CC

V

th_REC

V

th_DOM

Recessive

Dominant

Recessive