Philips Semiconductors

Objective specification

AU5783

J1850/VPW transceiver with supply control function

1999 May 11

FEATURES

Supports SAE/J1850 VPW standard for in-vehicle class B
multiplexing

Bus speed 10.4 kbit/s nominal

Drive capability 32 bus nodes

Low RFI due to output waveshape function

Direct battery operation with protection against +40V load dump
and 8 kV ESD

Bus terminals proof against automotive transients up to
+100V/150V and 8kV ESD

Power supply enable function

Very low sleep mode power consumption

4X transmission mode (41.6 kbit/s)

Diagnostic loop-back mode

Thermal overload protection

14-pin SOIC

DESCRIPTION

The AU5783 is a line transceiver being primarily intended for
in-vehicle multiplex applications. It provides interfacing between a
J1850 link controller and the physical bus wire. The device supports
the SAE/J1850 VPWM standard with a nominal bus speed of 10.4
kbit/s. For data upload and download purposes the 4X transmission
mode is supported with a nominal bus speed of 41.6 kbit/s. The
AU5783 provides protection against loss of ground conditions, thus
ensuring the network will be operational in case of an electronic
control unit loosing connection to ground potential. Low power
operation is supported through provision of a sleep mode with very
low power consumption. In addition an external voltage regulator
can be turned off via the AU5783 transceiver to further reduce the
overall power consumption. The voltage regulator will be activated
again upon detection of bus activity or upon a local wake-up event.

ORDERING INFORMATION

TYPE NUMBER

PACKAGE

TEMPERATURE

TYPE NUMBER

NAME

DESCRIPTION

VERSION

RANGE

AU5783D

SO14

plastic small outline package; 14 leads; body width 3.9 mm;
packed in tubes

SOT108-1

40 to +125

AU5783D-T

SO14

plastic small outline package; 14 leads; body width 3.9 mm;
shipped on tape and reel

SOT108-1

40 to +125

QUICK REFERENCE DATA

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

BAT.op

Operating supply voltage

amb

Operating ambient temperature range

+125

BAT.ld

Battery voltage

load dump, 1s

+40

BOH

Bus output voltage

250

< R

< 1.6 k

6.5

8.0

Bus input threshold

3.55

4.2

BAT.lp

Sleep mode supply current

Propagation delay

Tx to Rx

Bus output rise time

Philips Semiconductors

Objective specification

AU5783

J1850/VPW transceiver with supply control function

1999 May 11

PINNING

Pin configuration

SO14

AU5783

INH

GND

BUS

LWAKE

BAT

NSTB

GND

R/F

N.C.

LOAD

N.C.

4X/LOOP

SL01225

Figure 2. Pin configuration

Pin description

SYMBOL

PIN

DESCRIPTION

R/F

Rise/fall time control input; connect to
ground potential via a resistor

GND

Ground

4X/LOOP

Tx mode control input; low: normal mode;
high: 4X mode; float: loopback

NSTB

Network STandBy power control input;
low: transmit function disabled (low power
modes); high: transmit function enabled

Transmit data input; low: transmitter
passive; high: transmitter active

Receive data output; low: active bus
condition detected; high: otherwise

N.C.

Not connected

BAT

Battery supply input, 12V nominal

LWAKE

Local wake-up input, edge sensitive

INH

Activity indication flag (inhibit) output high
side driver; e.g., to control a voltage
regulator. Active high enables the
regulator

LOAD

Bus load in/output

BUS

Bus line transmit/receive input/output,
active high side driver

N.C.

Not connected

GND

Ground

FUNCTIONAL DESCRIPTION

The AU5783 is an integrated line transceiver IC that interfaces an
SAE/J1850 protocol controller IC to the vehicle's multiplex bus line.
It is primarily intended for automotive "Class B" multiplexing
applications in passenger cars using VPW (Variable Pulse Width)
modulated signals with a nominal transmission speed of 10.4 kbit/s.
The device provides transmit and receive capability as well as
protection to a J1850 electronic module.

A J1850 link controller feeds the transmit data stream to the
transceiver's TX input. The AU5783 transceiver waveshapes the TX
data input signal so as to minimize electromagnetic emission. The
bus output signal features controlled rise & fall characteristic
including rounded shape. A resistance being connected to the R/F
control input sets the bus output slew rate.

The LOAD output is connected to the physical bus line via an
external load resistor R

. The load resistor pulls the bus line to

ground potential being the default state e.g. when no transmitter
outputs an active state. This output ensures the J1850 network will
not be affected by a potential loss of ground condition at an
individual electronic control unit.

The AU5783 includes a bus receiver with filter function to minimize
susceptibility against interference. The logic state of the J1850 bus
signal is indicated at the RX output being connected to the J1850
link controller.

The AU5783 also provides advanced low-power modes to help
minimize ignition-off power consumption of an electronic control unit.
The bus receiver function is kept alive in the low-power modes. If an
active state is being detected on the bus line this will be indicated
via the RX output. By default the AU5783 enters the low-power
standby mode when the mode control inputs NSTB and 4X/LOOP
are not driven.

Ignition-off current draw can be reduced further by turning off the
voltage regulator being typically provided in an electronic control
unit. This is supported by the activity indication function of the
AU5783. In this application the activity indication flag INH will control
external devices such as a voltage regulator. To turn-off the INH flag
and thus the voltage regulator, the go to sleep command needs to
be applied to the Network Standby power control input,
e.g., NSTB = 0. The INH output is turned off after the sleep time-out
period thereby, reducing the power consumption of an electronic
control unit to an extremely low level.

The activity indication flag INH will be turned on again upon
detection of a remote wake-up condition (i.e. bus activity) or upon
detection of a local wake-up condition or a respective command
from the microcontroller. A local wake-up condition is detected when
an edge occurs at the wake-up input LWAKE. The INH flag will also
be turned on upon detection of a high input level at the mode control
input NSTB. Activation of the INH output enables external devices
e.g., a voltage regulator. This condition will power-up logic devices
e.g., a microcontroller in order to perform appropriate action,
e.g., activation of the AU5783 and the J1850 network.

The AU5783 provides a high-speed data transmission mode where
the bus output waveshape function is disabled. In this mode transmit
signals are output as fast as possible thus allowing higher data
rates, e.g. the so-called 4X mode with 41.6 kbit/s nominal speed.

The AU5783 also provides a loop-back mode for diagnostic
purpose, e.g. self-test of an electronic control unit. In loop-back
mode the bus transmit and receive functions are disabled thus

Philips Semiconductors

Objective specification

AU5783

J1850/VPW transceiver with supply control function

1999 May 11

essentially disconnecting an electronic control unit from the J1850
bus line. The TX signal is internally looped back to the RX output.

The AU5783 features special robustness at its BAT and BUS pins
hence the device is well protected for applications in the automotive
environment. Specifically the BAT input is protected against 40V
load dump and jump start condition. The BUS output is protected
against wiring fault conditions e.g. short circuit to ground and battery

voltage as well as typical automotive transients and electrostatic
discharge. In addition, an over-temperature shutdown function with
hysteresis is incorporated which protects the device under network
fault conditions. In case of the die temperature reaching the trip
point, the AU5783 will latch-off the transceiver function. The device
is reset on the first rising edge on the TX input after a decrease in
the junction temperature.

Table 1.

Control input summary

Z = Input connected to high impedance permitting it to float. Typically accomplished by turning off the output of a microcontroller.
X = Don't care; The input may be at either logic level.

NSTB

4X/LOOP

Mode

Bus

transmitter

BUS

RX (out)

INH

normal operation

active

high

low

high

normal operation

passive

float

bus state,
Note 2

high

4X transmit

active

high

low

high

4X transmit

passive

float

bus state,
Note 2

high

loop-back

passive

float

low

high

loop-back

passive

float

high

0 or Z

standby (default state after power on),
Note 1

off

float

bus state,
Note 5

high

1 > 0

go to sleep command, Note 4

off

float

bus state,
Note 5

float, Note 3

0 or Z

sleep, Note 4

off

float

bus state,
Note 5

float

NOTES:
1. After power-on, the AU5783 enters standby mode since the input pins NSTB and 4X/LOOP are assumed to be floating. In standby mode the

voltage regulator is enabled via the INH output, and therefore power is supplied to the microcontroller. When the microcontroller begins
operation it will normally set the control inputs NSTB high and 4X/LOOP to low state in order to start normal operation of the AU5783.

2. RX outputs the bus state. If the bus level is below the receiver threshold (i.e., all transmitters passive), then RX will be high. Otherwise, if the

bus level is above the receiver threshold (i.e., at least one transmitter is active), then RX will be low.

3. INH is turned off after a time-out period.
4. For entering the sleep mode (e.g., to deactivate INH), the "Go To Sleep" command needs to be applied. The "Go To Sleep" command is a

high-to-low transition on the NSTB input. When the "Go To Sleep" command is present, the INH flag is deactivated. This signal can be used
to turn-off the voltage regulator of an electronic module. After the voltage regulator is turned off the microcontroller is no longer supplied and
the NSTB input will be floating. The INH output will be set again upon detection of bus activity or occurrence of a local wake-up event.

5. In standby and sleep mode, the detection of a wake-up condition (e.g., high level on BUS) will be signalled on the output RX.

Part Number AU5783