TLE7257 Datasheet, PDF (10/31 Pages) Infineon Technologies AG – LIN Transceiver

TLE7257
Functional Description
4.4
Sleep Mode
Sleep mode is a low power mode with quiescent current consumption reduced to a minimum while the device is
still able to wake-up by a message on the LIN bus.
After a power-up event the TLE7257 enters Sleep mode by default. The EN pin has an internal pull-down resistor
and the TLE7257 remains in Sleep mode until the external microcontroller applies a logical “high” signal at the EN
input.
To switch the TLE7257 from Normal Operation mode to Sleep mode, the EN input has to be set to “low”.
Conversely a logical “high” signal on the EN input sets the device directly back to Normal Operation mode (see
Figure 4). The TLE7257 can only enter Sleep mode from Normal Operation mode.
EN
RxD: „high“ or „low“ depending on
RxD
the signals on the LIN bus
TxD
Data transmission
t_Mode
t
RxD: “high“ because of external pull-up
resistor to the microcontroller supply voltage
t
TxD: „high impedance“
t
INH
INH: „high impedance“
Normal Operation mode
t
Sleep mode
TLE7257_SLEEP_MODE
Figure 6 Entering Sleep mode from Normal Operation mode
While the TLE7257 is in Sleep mode the following functions are available:
• The transmitter is turned off.
• The receiver is turned off.
• The BUS output is terminated to V_S via the internal termination resistor R_BUS (see Figure 1).
• The RxD output is “high” if a pull-up resistor is connected to the external microcontroller supply.
• The TxD input is disabled and the internal pull-up current source is switched off.
• The INH output is switched off and is floating.
• The bus wake-up comparator is active and will cause transition to Standby mode in case of a wake-up event.
• In Sleep mode only the power-on reset level of the undervoltage detection is active (see “Undervoltage
Detection” on Page 15).
• The EN input remains active. A “high” signal on the EN input triggers a transition to Normal Operation mode.
Data Sheet
10
Rev. 1.0, 2013-10-16