TLE7250G

Functional Description

Data Sheet

9

Rev. 1.0, 2012-03-01

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

•

The undervoltage monitoring at the power supply

V

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

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

•

The undervoltage monitoring on the power supply

V

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

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

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

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.