TLE7250G Datasheet, PDF (9/22 Pages) Infineon Technologies AG – High Speed CAN Transceiver

TLE7250G
Functional Description
4.3
Normal-operating Mode
In the normal-operating mode, the HS CAN transceiver TLE7250G sends the serial data stream on the TxD pin to
the CAN bus. The data on the CAN bus is displayed at the RxD pin simultaneously. In the normal-operating mode,
all functions of the TLE7250G are active:
• The transmitter is active and drives data from the TxD to the CAN bus.
• The receiver is active and provides the data from the CAN bus to the RxD pin.
• The bus biasing is set to V_CC/2.
• The undervoltage monitoring at the power supply V_CC is active.
To enter the normal-operating mode, set the pin NRM to logical “high” and the pin NEN to logical “low” (see
Table 2 or Figure 4). Both pins, the NEN pin and the NRM pin have internal pull-up resistors to the power-supply
V_CC.
4.4
Receive-only Mode
The receive-only mode can be used to test the connection of the bus medium. The TLE7250G can still receive
data form the bus, but the transmitter is disabled and hence, no data can be sent to the CAN bus. All other
functions are active:
• The transmitter is disabled and data, which is available on the TxD pin, is blocked and not sent to the CAN bus.
• The receiver is active and provides the data from the CAN bus to the RxD output pin.
• The bus biasing is set to V_CC/2.
• The undervoltage monitoring on the power supply V_CC is active.
To enter the receive-only mode, set the pin NRM to logical “low” and the pin NEN to logical “low” (see Table 2 or
Figure 4). In case the receive-only mode is not used, the NRM pin can be left open.
4.5
Stand-by Mode
The stand-by mode is an idle mode of the TLE7250G with optimized power consumption. In the stand-by mode,
the TLE7250G can not send or receive any data. The transmitter and the receiver are disabled. Both CAN bus
pins, CANH and CANL are connected to GND via the input resistors.
• The transmitter is disabled.
• The receiver is disabled.
• The input resistors of the receiver unit are connected to GND.
• The undervoltage monitoring at the power supply V_CC is active.
To enter the stand-by mode, set the pin NEN to logical “high”, the logical state of the NRM pin has no influence on
the mode selection (see Table 2 or Figure 4). Both pins, the NEN and the NRM pin have an internal pull-up
resistor to the power-supply V_CC. If the stand-by mode is not used in the application, the NEN pin needs to be
connected to GND.
In case the NRM pin is set to logical “low” in the stand-by mode, the internal pull-up resistor causes an additional
quiescent current from V_CC to GND, therefore it is recommended to set the NRM pin to logical “high” in stand-by
mode or leave the pin open, if the receive-only mode is not used in the application.
4.6
Power-down state
The power-down state means that the TLE7250G is not supplied. In power-down state, the differential input
resistors of the receiver stage are switched off. The CANH and CANL bus interface of the TLE7250G acts as high-
impedance input with a very small leakage current. The high-ohmic input does not influence the “recessive” level
of the CAN network and allows an optimized EME performance of the entire CAN network.
Data Sheet
9
Rev. 1.0, 2012-03-01