TLE7250GVIO

Functional Description

Data Sheet

7

Rev. 1.0, 2012-03-14

The TLE7250GVIO is a High Speed CAN transceiver, operating as an interface between the CAN controller and

the physical bus medium. A HS CAN network is a two-wire, differential network, which allows data transmission

rates up to 1 Mbps. The characteristics of a HS CAN network are the two signal states on the CAN bus: “dominant”

and “recessive” (see Figure 3).

The CANH and CANL pins are the interface to the CAN bus and both pins operate as an input and output. The

RxD and TxD pins are the interface to the microcontroller. The TxD pin is the serial data input from the CAN

controller, and the RxD pin is the serial data output to the CAN controller. As shown in Figure 1, the HS CAN

transceiver TLE7250GVIO includes a receiver and a transmitter unit, allowing the transceiver to send data to the

bus medium and monitor the data from the bus medium at the same time. The HS CAN transceiver TLE7250GVIO

converts the serial data stream available on the transmit data input TxD, into a differential output signal on the

CAN bus, provided by the CANH and CANL pins. The receiver stage of the TLE7250GVIO monitors the data on

the CAN bus and converts them to a serial, single-ended signal on the RxD output pin. A logical “low” signal on

the TxD pin creates a “dominant” signal on the CAN bus, followed by a logical “low” signal on the RxD pin (see

Figure 3). The feature of broadcasting data to the CAN bus and listening to the data traffic on the CAN bus

simultaneously is essential to support the bit-to-bit arbitration within CAN networks.

The voltage levels for HS CAN transceivers are defined by the ISO 11898-2 and the ISO 11898-5 standards.

Whether a data bit is “dominant” or “recessive” depends on the voltage difference between the CANH and CANL

pins:

V

In comparison with other differential network protocols, the differential signal on a CAN network can only be larger

than or equal to 0 V. To transmit a “dominant” signal to the CAN bus, the differential signal

V

equal to 1.5 V. To receive a “recessive” signal from the CAN bus, the differential

V

0.5 V.

“Partially-supplied” High Speed CAN networks are those where the CAN bus nodes of one common network have

different power supply conditions. Some nodes are connected to the common power supply, while other nodes

are disconnected from the power supply and in power-down state. Regardless of whether the CAN bus subscriber

is supplied or not, each subscriber connected to the common bus media must not interfere with the

communication. The TLE7250GVIO is designed to support “partially-supplied” networks. In the power-down state,

the receiver input resistors are switched off and the transceiver input has a high resistance.

The voltage level at the digital input TxD and the digital output RxD is determined by the power supply level at the

V

compatible with microcontrollers having 5 V or 3.3 V I/O supply. Usually, the

V

is connected to same power supply as the I/O power supply of the microcontroller.