TLE7257

Functional Description

Data Sheet

9

Rev. 1.0, 2013-10-16

While the TLE7257 is in Normal Operation mode the following functions are available:

•

The transmitter is turned on; data on the TxD input are driven on the LIN bus.

•

The receiver is turned on; data on the LIN bus are monitored and signaled on the RxD output.

•

The BUS pin is terminated to

V

•

The TxD input is pulled up via a current source to the internal power supply of the TLE7257.

•

The INH output is switched on.

•

The bus wake-up comparator is turned off.

•

The two-level undervoltage detection is active. In case

V

TLE7257 blocks the transmitter and receiver. In case

V

TLE7257 changes the operation mode to Standby mode after recovery (see “Undervoltage Detection” on

Page 15).

•

The EN input is active. A “low” signal on the EN input triggers a transition to Sleep.

After a mode change to Normal Operation the TLE7257 requires a logical “high” signal for the time

t

TxD input before releasing the data communication (see Figure 5). The transmitter remains deactivated as long

as the signal on the TxD input remains logical “low”, preventing possible bus communication disturbance.

4.3

Standby Mode

The Standby mode is entered automatically after bus wake-up event.

In Standby mode no communication to the LIN bus is possible. The transmitter and the receiver are disabled.

While the TLE7257 is in Standby mode the following functions are available:

•

The transmitter is turned off, the TxD input is inactive and the bus output is permanent “recessive”.

•

The receiver is turned off.

•

The RxD output indicates a wake-up event (see Figure 4 and Table 1).

•

The BUS pin is terminated to

V

•

The TxD input is pulled up with a current source to the internal power supply of the TLE7257.

•

The INH output is switched on.

•

In Standby mode only the power-on reset level of the undervoltage detection is active (see “Undervoltage

Detection” on Page 15).

•

The EN input is active. A “high” signal on the EN input triggers a transition to Normal Operation mode (see

Figure 5).