TLE7250G Datasheet, PDF (7/22 Pages) Infineon Technologies AG – High Speed CAN Transceiver

TLE7250G
Functional Description
The TLE7250G is a High Speed CAN transceiver, operating as an interface between the CAN controller and the
physical bus medium. An HS CAN network is a two-wire, differential network, which allows data transmission rates
up to 1 Mbps. The characteristics of an 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 TLE7250G 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 TLE7250G
converts the serial data stream which is 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 TLE7250G 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_DIFF = V_CANH - V_CANL.
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_DIFF is larger than or
equal to 1.5 V. To receive a “recessive” signal from the CAN bus, the differential V_DIFF is smaller than or equal to
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 TLE7250G is designed to support “partially-supplied” networks. In power-down state, the
receiver input resistors are switched off and the transceiver input has a high resistance.
Data Sheet
7
Rev. 1.0, 2012-03-01