TLE9255WLC datasheet(10/100 Pages) INFINEON

10 / 100 page

Data Sheet

Rev. 1.02 2018-02-02

TLE9255W

High Speed CAN Functional Description

The TLE9255W is a HS 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

5 MBit/s. HS CAN networks have two signal states on the CAN bus (see Figure 3):

•dominant

•recessive

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

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

controller. The RxD pin is the serial data output to the CAN controller. The HS CAN transceiver TLE9255W

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

monitoring the data from the bus medium at the same time (see Figure 1). The TLE9255W converts the serial

data stream, which is available on the transmit data input TxD, to a differential output signal on the CAN bus,

provided by the CANH and CANL pins. The receiver stage of the TLE9255W monitors the data on the CAN bus

and converts it to a serial, single-ended signal on the RxD output pin. A “low” signal on the TxD pin creates a

dominant signal on the CAN bus, followed by a “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.

ISO 11898-2 (2016) defines the voltage levels for HS CAN transceivers. Whether a data bit is dominant or

recessive depends on the voltage difference between the CANH and CANL pins:

VDiff = VCANH - VCANL

To transmit a dominant signal to the CAN bus the amplitude of the differential signal VDiff is ≥ 1.5 V. To receive

a recessive signal from the CAN bus the amplitude of the differential VDiff is ≤ 0.5 V.

Partially supplied High-Speed CAN networks have CAN bus nodes with 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 TLE9255W

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.

For permanently supplied ECUs, the TLE9255W provides low power modes. In these low power modes, the

current consumption of the TLE9255W is optimized to a minimum, while the TLE9255W can still recognize

wake-up patterns or wake-up frames on the CAN bus and signal the wake-up event to the external

microcontroller.

The voltage level on the digital input TxD and the digital output RxD is determined by the reference supply

level at the VIO pin. Depending on the voltage level at the VIO pin, the signal levels on the logic pins (CSN, SCLK,

MOSI, MISO, TxD and RxD) are compatible to microcontrollers having a 5 V or 3.3 V I/O supply. It is highly

recommended that the digital power supply of VIO of the transceiver is connected to the I/O power supply of

the microcontroller; this is the way it is intended to be used (see Figure 53).

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