Philips TJA1053 Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TJA1053

Fault-tolerant CAN transceiver

Preliminary speciﬁcation File under Integrated Circuits, IC18

1997 Oct 15

Philips Semiconductors Preliminary speciﬁcation

Fault-tolerant CAN transceiver TJA1053

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

• Low RFI due to built-in slope control function

• Fully integrated receiver filters

• Permanent dominant monitoring of TXD.

Bus failure management

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

• Automatic switching to single-wire mode in the event of bus failure

• Automatic reset to differential mode if bus failure is removed.

Protection

• Short-circuit proof to battery and ground in 12 V powered systems

• Thermally protected

• Bus lines protected against transients in an automotive

environment

• An unpowered node does not disturb the bus lines.

Support for low-power modes

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

• Power-on reset flag on the output.

GENERAL DESCRIPTION

The TJA1053 is the interface between the CAN protocol controller and the physical bus. It is primarily intended for low-speed applications, up to 125 kbaud, in passenger cars. The device provides differential transmit capability but will switch in error conditions to a single-wire transmitter and/or receiver. The TJA1053 is derived from the PCA82C252.

1. It is better equipped for networks with more than

15 nodes

2. A timer has been integrated at the TXD input to

prevent a permanent dominant state

3. Reduced supply current in V

standby mode

4. CANH output driver is disabled in the event that CANH

is short-circuited to battery failure mode.

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MIN. UNIT

BAT

supply voltage 4.75 − 5.25 V battery voltage no time limit −0.3 − +27 V

operating 6.0 − 27 V load dump −−40 V

sleep

CANH,VCANL

sleep mode current VCC=0V; V

=12V − 65 −µA

BAT

CANH, CANL input voltage VCC= 0 to 5.5 V; V

BAT

≥ 0V;

−10 − +27 V

no time limit V

= 0 to 5.5 V; V

BAT

≥ 0V;

−40 − +40 V

t < 0.1 ms; load dump

DROP(H)

DROP(L)

amb

CANH transmitter drop voltage I CANL transmitter drop voltage I

=40mA −−1.4 V

CANH

=40mA −−1.4 V

CANL

propagation delay TXD to RXD − 1 −µs bus output fall time 90% to 10% − 0.5 −µs bus output rise time 10% to 90% − 0.5 −µs operating ambient temperature −40 − +125 °C

1997 Oct 15 2

Philips Semiconductors Preliminary speciﬁcation

Fault-tolerant CAN transceiver TJA1053

ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

PACKAGE

TJA1053T SO14 plastic small outline package; 14 leads; body width 3.9 mm SOT108-1

BLOCK DIAGRAM

handbook, full pagewidth

WAKE

STB

TXD

INH

BAT

1 7

5 6

TIMER

WAKE-UP STANDBY

CONTROL

TEMPERATURE

PROTECTION

DRIVER

TJA1053

12.5 kΩ

RTL

CANH

CANL

RTH

NERR

RXD

FAILURE DETECTOR

PLUS WAKE UP

PLUS TIME-OUT

GND

FILTER

RECEIVER

FILTER

MGL181

Fig.1 Block diagram.

1997 Oct 15 3

Philips Semiconductors Preliminary speciﬁcation

Fault-tolerant CAN transceiver TJA1053

PINNING

SYMBOL PIN DESCRIPTION

INH 1 inhibit output for switching external

5 V regulator

TXD 2 transmit data input, when LOW bus

data will be dominant, when HIGH bus data will be recessive

RXD 3 receive data output, when LOW bus

data will be dominant

NERR 4 error output pin, when LOW a bus

error exists

STB 5 not standby digital control input

signal (active LOW) EN 6 enable digital control input signal WAKE 7 not wake input signal, when pulled

down INH becomes active for

wake-up (active LOW) RTH 8 termination resistor, CANH line will

be high-impedance with certain bus

errors RTL 9 termination resistor, CANL line will be

high-impedance with certain bus

errors V

10 supply voltage (+5 V)

CANH 11 high voltage bus line, will be HIGH in

dominant state CANL 12 low voltage bus line, will be LOW in

dominant state GND 13 ground BAT 14 battery voltage

handbook, halfpage

1INH 2

TXD GND

RXD CANL

NERR CANH

STB V

EN RTL

WAKE RTH

TJA1053T

5 6 7

MGL182

14 BAT 13 12 11 10

9 8

Fig.2 Pin configuration.

1997 Oct 15 4

Philips Semiconductors Preliminary speciﬁcation

Fault-tolerant CAN transceiver TJA1053

FUNCTIONAL DESCRIPTION

The TJA1053 is the interface between the CAN protocol controller and the physical bus. It is primarily intended for low speed applications, up to 125 kBaud, in passenger cars. The device provides differential transmit capability to the bus and differential receive capability to the CAN controller.

To reduce RF interference the rise and fall slope are limited. This allows the use of an unshielded twisted pair or a parallel pair of wires for the bus. Moreover, it supports transmission capability on either bus wire if one of the bus wires is corrupted. The failure detection logic automatically selects a suitable transmission mode.

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

A timer has been integrated at the TXD input. This timer prevents the TJA1053 to drive the bus lines to permanent dominant state.

Failure detector

This time is needed to avoid false triggering by external RF fields. Recovery from these failures is detected automatically after a certain time-out (filtering) and no transmission is lost. The CANH driver and the RTH pin are switched off in the event of failure 3.

Failures 4 and 7 initially result in a permanent dominant level at RXD. After a time-out, the CANL driver and the RTL pin are switched off. Only a weak pull-up at RTL remains. Reception continues by switching to the single-wire mode via CANH. 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 seven wiring failures occur, the output NERR will be made LOW. On error recovery, NERR will be made HIGH again.

During all single-wire transmissions, the EMC performance (both immunity and emission) is worse than in the differential mode. 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 the single-wire mode, low frequency noise cannot be distinguished from the required signal.

The failure detector is active in the normal operation mode and detects the following single bus failures and switches to an appropriate mode:

1. CANH wire interrupted

2. CANL wire interrupted

3. CANH short-circuited to battery

4. CANL short-circuited to ground

5. CANH short-circuited to ground

6. CANL short-circuited to battery

7. CANL mutually shorted to CANH. The differential receiver threshold is set at −2.9 V.

This ensures correct reception in the normal operating modes and, in the event of failures 1, 2 and 5 with a noise margin as high as possible. These failures, or recovery from them, do not destroy ongoing transmissions.

Failures 3 and 6 are detected by comparators connected to CANH and CANL, respectively. If the comparator threshold is exceeded for a certain period of time, the reception is switched to the single-wire mode.

Low power modes

The transceiver provides 3 low power modes which can be entered and exited via pins

STB and EN (see Table 1).

The sleep mode is the mode with the lowest power consumption. The INH pin is switched to high-impedance for deactivation of external voltage regulators. CANL is biased to the battery voltage via the RTL output. If the supply voltage is provided the RXD and NERR will signal the wake-up interrupt

The V

standby mode will react the same as the sleep

BAT

mode with an active INH output. The VCC standby mode is the V

standby with RTL

BAT

switched to the VCC voltage. In this mode the NERR output signals the V

power-on flag and the RXD output will

BAT

show the wake-up interrupt.

1997 Oct 15 5

Philips Semiconductors Preliminary speciﬁcation

Fault-tolerant CAN transceiver TJA1053

Wake-up requests are recognized by the transceiver when a dominant signal is detected on either bus line or if the WAKE pin is connected to ground. On a wake-up request the transceiver will set the INH output which can be used to activate the external VCC voltage regulator. If VCC is provided the wake-up request can be read on the NERR or RXD outputs, on which the external microcontroller can wake up the transceiver (switch to normal operating mode) via STB and EN.

To prevent false wake-up due to transients or RF fields, wake-up voltage threshold 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 increased power consumption should errors 3, 4 and 7 occur.

Power on

After power-on V

is switched on, the INH pin will

BAT

become HIGH and an internal power-on flag will be set. This flag can be read via the NERR pin (STB = 1, EN = 0) and will be reset by entering the normal operation mode.

Table 1 Truth table of CAN transceiver

The EN and

STB pins will internally be set to LOW level, if the VCC voltage is below a certain threshold level, to provide fail safe functionality.

Protections

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

If the junction temperature exceeds a maximum value, the transmitter output stages are disabled. Because the transmitter is 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 IC will remain operating.

The CANH and CANL inputs are protected against electrical transients which may occur in an automotive environment.

STB EN MODE INH NERR RXD RTL

00V

BAT

0 0 sleep

standby

(2)

(1)

HIGH active LOW wake-up interrupt signal if VCC is present switched to V

ﬂoating switched to V 0 1 go to sleep command ﬂoating switched to V 10VCC standby

1 1 normal operation mode HIGH active LOW error ﬂag HIGH = receive;

(3)

HIGH active LOW V

power-on ﬂag

BAT

active LOW wake-up interrupt

switched to V

switched to V LOW = dominant received data

Notes

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

2. If go to sleep command was used before (EN may turn LOW as V

drops, without affecting internal functions

because of fail safe functionality).

3. V

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

BAT

BAT BAT BAT CC

1997 Oct 15 6

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