Philips TJA1054A User Manual

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TJA1054A

Fault-tolerant CAN transceiver

Product speciﬁcation Supersedes data of 2002 Feb 11

2004 Mar 23

Philips Semiconductors Product speciﬁcation

Fault-tolerant CAN transceiver TJA1054A

FEATURES Optimized for in-car low-speed communication

• Baud rate up to 125 kBaud

• Up to 32 nodes can be connected

• Supports unshielded bus wires

• Very low ElectroMagnetic Emission (EME) due to

built-in slope controlfunction and a very good matching of the CANL and CANH bus outputs

• Good ElectroMagnetic Immunity (EMI) in normal operating mode and in low power modes

• Fully integrated receiver filters

• Transmit Data (TxD) dominant time-out function.

Bus failure management

• Supports single-wire transmission modes with ground offset voltages up to 1.5 V

• Automatic switching to single-wire mode in the event of bus failures, even when the CANH bus wire is short-circuited to V

• Automatic reset to differential mode if bus failure is removed

• Full wake-up capability during failure modes.

Protections

• Bus pins short-circuit safe to battery and to ground

• Thermally protected

• Bus lines protected against transients in an automotive

environment

• An unpowered node does not disturb the bus lines.

GENERAL DESCRIPTION

The TJA1054A is the interface between the protocol controller and the physical bus wires in a Controller Area Network (CAN). It is primarily intended for low-speed applications up to 125 kBaud in passenger cars. The device provides differential receive and transmit capability but will switch to single-wire transmitter and/or receiver in error conditions.

The TJA1054A is the ESD improved version of the TJA1054. For an overview of the differences between the TJA1054 and the TJA1054A, please refer to “Appendix A”.

The TJA1054AT is, as the TJA1054T, pin and downwards compatiblewiththePCA82C252TandtheTJA1053T. This means that these two devices can be replaced by the TJA1054AT or the TJA1054T with retention of all functions.

Themost important improvements of the TJA1054 and the TJA1054A with respect to the PCA82C252 and the TJA1053 are:

• Very low EME due to a very good matching of the CANL and CANH output signals

• Good EMI, especially in low power modes

• Full wake-up capability during bus failures

• Extended bus failure management including

short-circuit of the CANH bus line to V

• Support for easy system fault diagnosis

• Two-edge sensitive wake-up input signal via pin WAKE.

Support for low power modes

• Low current sleep and standby mode with wake-up via the bus lines

• Power-on reset flag on the output.

ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

PACKAGE

TJA1054AT SO14 plastic small outline package; 14 leads; body width 3.9 mm SOT108-1 TJA1054AU − bare die; 1990 × 2730 × 375 µm −

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Philips Semiconductors Product speciﬁcation

Fault-tolerant CAN transceiver TJA1054A

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

BAT

CANH

CANL

∆V

PD(L)

CANH

CANL

supply voltage on pin V

4.75 − 5.25 V

battery voltage on pin BAT no time limit −0.3 − +40 V

operating mode; note 1 5.0 − 27 V load dump −−40 V

battery current on pin BAT sleep mode; VCC=0V;

=12V

BAT

CANH bus line voltage VCC= 0 to 5.0 V; V

BAT

≥ 0V;

− 30 50 µA

−27 − +40 V

no time limit

CANL bus line voltage VCC= 0 to 5.0 V; V

BAT

≥ 0V;

−27 − +40 V

no time limit

CANH bus line transmitter

= −40 mA −−1.4 V

CANH

voltage drop CANL bus line transmitter

=40mA −−1.4 V

CANL

voltage drop propagation delay TXD (LOW)

− 1 −µs

to RXD (LOW) bus line output rise time between 10% and 90%;

− 0.6 −µs

C1 = 10 nF; see Fig.5

bus line output fall time between 10% and 90%;

− 0.3 −µs

C1 = 1 nF; see Fig.5

virtual junction temperature −40 − +150 °C

Note

1. A local or remote wake-up event will be signalled at the transceiver pins RXD and NERR if V

(see Table 2).

=5.3Vto27V

BAT

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Philips Semiconductors Product speciﬁcation

Fault-tolerant CAN transceiver TJA1054A

BLOCK DIAGRAM

handbook, full pagewidth

WAKE

STB

TXD

ERR

RXD

INH

BAT

1 7

5 6

TIMER

GND

WAKE-UP STANDBY

CONTROL

FAILURE DETECTOR

PLUS WAKE-UP PLUS TIME-OUT

TEMPERATURE

PROTECTION

DRIVER

TJA1054A

RECEIVER

FILTER

RTL

CANH

CANL

RTH

MGU383

Fig.1 Block diagram.

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Philips Semiconductors Product speciﬁcation

Fault-tolerant CAN transceiver TJA1054A

PINNING

SYMBOL PIN DESCRIPTION

INH 1 inhibit output for switching an external voltage regulator if a wake-up signal occurs TXD 2 transmit data input for activating the driver to the bus lines RXD 3 receive data output for reading out the data from the bus lines ERR 4 error, wake-up and power-on indication output; active LOW in normaloperating mode when the bus

has a failure, and in low power modes (wake-up signal or in power-on standby)

STB 5 standby digital control signal input (active LOW); together with the input signal on pin EN this input

determines the state of the transceiver (in normal and low power modes); see Table 2 and Fig.3

EN 6 enable digital control signal input; together with the input signal on pin STB this input determines

the state of the transceiver (in normal and low power modes); see Table 2 and Fig.3 WAKE 7 local wake-up signal input (active LOW); both falling and rising edges are detected RTH 8 termination resistor connection; in case of a CANH bus wire error the line is terminated with a

predeﬁned impedance RTL 9 termination resistor connection; in case of a CANL bus wire the line is terminated with a predeﬁned

impedance V

CANH 11 HIGH-level CAN bus line CANL 12 LOW-level CAN bus line GND 13 ground BAT 14 battery supply voltage

10 supply voltage

handbook, halfpage

1INH 2

TXD GND

RXD CANL

ERR CANH

STB V

WAKE RTH

TJA1054AT

5 6

EN RTL

Fig.2 Pin configuration.

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MGU379

14 BAT 13 12 11 10

9 8

Philips Semiconductors Product speciﬁcation

Fault-tolerant CAN transceiver TJA1054A

FUNCTIONAL DESCRIPTION

The TJA1054A is the interface between the CAN protocol controller and the physical wires of the CAN bus (see Fig.7). It is primarily intended for low-speed applications, up to 125 kBaud, in passenger cars. The device provides differential transmit capability to the CAN bus and differential receive capability to the CAN controller.

To reduce EME, the rise and fall slopes are limited. This allows the use of an unshielded twisted pair or a parallel pair of wires for the bus lines. Moreover, the device supportstransmission capability on either bus line if one of the wires is corrupted. The failure detection logic automatically selects a suitable transmission mode.

In normal operating mode (no wiring failures) the differential receiver is output on pin RXD (see Fig.1). The differential receiver inputs are connected to pins CANH and CANL through integrated filters. The filtered input signals are also used for the single-wire receivers. The receivers connected to pins CANH and CANL have threshold voltages that ensure a maximum noise margin in single-wire mode.

A timer function (TxD dominant time-out function) has been integrated to prevent the bus lines from being driven into a permanent dominant state (thus blocking the entire network communication) due to a situation in which pin TXD is permanently forced to a LOW level, caused by a hardware and/or software application failure.

If the duration of the LOW level on pin TXD exceeds a certain time, the transmitter will be disabled. The timer will be reset by a HIGH level on pin TXD.

Failure detector

The failure detector is fully active in the normal operating mode. After the detection of a single bus failure the detector switches to the appropriate mode (see Table 1). The differential receiver threshold voltage is set at −3.2 V typical (VCC= 5 V). This ensures correct reception with a noise margin as high as possible in the normal operating mode and in the event of failures 1, 2, 5 and 6a. These failures, or recovery from them, do not destroy ongoing transmissions. The output drivers remain active, the termination does not change and the receiver remains in differential mode (see Table 1).

Failures 3, 3a and 6 are detected by comparators connected to the CANH and CANL bus lines. Failures 3 and 3a are detected in a two-step approach. If the CANH bus line exceeds a certain voltage level, the differential comparator signals a continuous dominant condition. Because of inter operability reasons with the predecessor products PCA82C252 and TJA1053, after a first time-out the transceiver switches to single-wire operation through CANH. If the CANH bus line is still exceeding the CANH detection voltage for a second time-out, the TJA1054A switches to CANL operation; the CANH driver is switched off and the RTH bias changes to the pull-down current source. The time-outs (delays) are needed to avoid false triggering by external RF fields.

Table 1 Bus failures

FAILURE DESCRIPTION

1 CANH wire interrupted on on on on differential 2 CANL wire interrupted on on on on differential 3 CANH short-circuited to battery weak; note 1 on off on CANL

3a CANH short-circuited to V

4 CANL short-circuited to ground on weak; note 2 on off CANH 5 CANH short-circuited to ground on on on on differential 6 CANL short-circuited to battery on weak; note 2 on off CANH

6a CANL short-circuited to V

7 CANL and CANH mutually

short-circuited

Notes

1. A weak termination implies a pull-down current source behaviour of 75 µA typical.

2. A weak termination implies a pull-up current source behaviour of 75 µA typical.

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TERMINATION

CANH (RTH)

weak; note 1 on off on CANL

on on on on differential on weak; note 2 on off CANH

TERMINATION

CANL (RTL)

CANH

DRIVER

CANL

DRIVER

RECEIVER

MODE

Philips Semiconductors Product speciﬁcation

Fault-tolerant CAN transceiver TJA1054A

Failure 6 is detected if the CANL bus line exceeds its comparator threshold for a certain period of time. This delay is needed to avoid false triggering by external RF fields. After detection of failure 6, the reception is switched to the single-wire mode through CANH; the CANL driver is switched off and the RTL bias changes to the pull-up current source.

Recovery from failures 3, 3a and 6 is detected automatically after reading a consecutive recessive level by corresponding comparators for a certain period of time.

Failures 4 and 7 initially result in a permanent dominant level on pin RXD. After a time-out the CANL driver is switched off and the RTL bias changes to the pull-up current source. Reception continues by switching to the single-wire mode via pins CANH or CANL. When failures 4 or 7 are removed, the recessive bus levels are restored. If the differential voltage remains below the recessive threshold level for a certain period of time, reception and transmission switch back to the differential mode.

If any of the wiring failure occurs, the output signal on pin ERR will be set to LOW. On error recovery, the output signal on pin ERR will be set to HIGH again. In case of an interrupted open bus wire, this failure will be detected and signalled only if there is an open wire between the transmittingand receiving node(s). Thus, during open wire failures, pin ERR typically toggles.

During all single-wire transmissions, EMC performance (both immunity and emission) is worse than in the differential mode. The integrated receiver filters suppress any HF noise induced into the bus wires. The cut-off frequency of these filters is a compromise between propagation delay and HF suppression. In single-wire mode, LF noise cannot be distinguished from the required signal.

Low power modes

The transceiver provides three low power modes which can be entered and exited via STB and EN (see Table 2 and Fig.3).

The sleep mode is the mode with the lowest power consumption. Pin INH is switched to HIGH-impedance for deactivation of the external voltage regulator. Pin CANL is biased to the battery voltage via pin RTL. If the supply voltage is provided, pins RXD and ERR will signal the wake-up interrupt.

The standby mode operates in the same way as the sleep mode but with a HIGH level on pin INH.

The power-on standby mode is the same as the standby mode, however, in this mode the battery power-on flag is shown on pin ERR instead of the wake-up interrupt signal. The output on pin RXD will show the wake-up interrupt. This mode is only for reading out the power-on flag.

Table 2 Normal operating and low power modes

MODE

Goto-sleep

STB

PIN EN

LOW HIGH wake-up

command Sleep LOW LOW

interruptsignal;

(4)

notes 1 2 and 3

PIN ERR PIN RXD PIN RTL

LOW HIGH LOW HIGH

wake-up interruptsignal; notes 1 2 and 3

Standby LOW LOW Power-on

standby

Normal operating

HIGH LOW V

power-on

BAT

ﬂag; notes 1 and 5

wake-up interruptsignal; notes 1 2 and 3

HIGH HIGH error ﬂag no error ﬂag dominant

received data

Notes

1. If the supply voltage VCC is present.

2. Wake-up interrupts are released when entering normal operating mode.

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recessive received data

SWITCHED

BAT

Philips Semiconductors Product speciﬁcation

Fault-tolerant CAN transceiver TJA1054A

3. A local or remote wake-up event will be signalled at the transceiver pins RXD and NERR if V

=5.3Vto27V.

BAT

4. In case the goto-sleep command was used before. When VCC drops, pin EN will become LOW, but due to the fail-safe functionality this does not effect the internal functions.

5. V

Wake-up requests are recognized by the transceiver through two possible channels:

• The bus lines for remote wake-up

• Pin WAKE for local wake-up.

In order to wake-up the transceiver remotely through the bus lines, a filter mechanism is integrated. This mechanism makes sure that noise and any present bus failure conditions do not result into an erroneous wake-up. Because of this mechanism it is not sufficient to simply pull the CANH or CANL bus lines to a dominant level for a certain time. To guarantee a successful remote wake-up under all conditions, a message frame with a dominant phase of at least the maximum specified t it is required.

A local wake-up through pin WAKE is detected by a rising or falling edge with a consecutive level with the maximum specified t

Onawake-uprequestthetransceiverwillsetthe output on

power-on flag will be reset when entering normal operating mode.

BAT

Pin INH will be set to a HIGH level again by the following events only:

• V

BAT

• Rising or falling edge on pin WAKE

• A message frame with a dominant phase of at least the

maximum specified t pin STB is at a LOW level

• Pin STB goes to a HIGH level with VCC active. To provide fail-safe functionality, the signals on pins STB

and EN will internally be set to LOW when VCCis below a certain threshold voltage (V

CANH

or t

CANL

Power-on

After power-on (V willbecome HIGH and an internal power-onflagwill be set.

WAKE

This flag can be read in the power-on standby mode through pin ERR (STB = 1; EN = 0) and will be reset by entering the normal operating mode.

power-on (cold start)

CANH

switched on) the signal on pin INH

BAT

or t

CANL

CC(stb)

, while pin EN or

pin INHtoHIGH which can be used to activate the external supply voltage regulator.

If VCCis provided the wake-up request can be read on the ERR or RXD outputs, so the external microcontroller can activate the transceiver (switch to normal operating mode) via pins STB and EN.

To prevent a false remote wake-up due to transients or RF fields, the wake-up voltage levels have to be maintained for a certain period of time. In the low power modes the failure detection circuit remains partly active to prevent an increased power consumption in the event of failures 3, 3a, 4 and 7.

To prevent a false local wake-up during an open wire at

Protections

A current limiting circuit protects the transmitter output stages against short-circuit to positive and negative battery voltage.

If the junction temperature exceeds the typical value of 165 °C, the transmitter output stages are disabled. Becausethetransmitteris responsible for the major part of the power dissipation, this will result in a reduced power dissipation and hence a lower chip temperature. All other parts of the device will continue to operate.

Thepins CANHand CANL are protected against electrical transients which may occur in an automotive environment.

pin WAKE, this pin has a weak pull-up current source towards V

. However, in order to prevent EMC issues, it

BAT

is recommended to connect a not used pin WAKE to pin BAT. Pin INH is set to floating only if the goto-sleep command is entered successfully. To enter a successful goto-sleep command under all conditions, this command must be kept stable for the maximum specified t

h(sleep)

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+ 17 hidden pages