Philips Semiconductors
Product data
SAE/J1850/VPW transceiver
AU5780A
FEATURES
multiplexing
•
Supports SAE/J1850 VPW standard for in-vehicle class B
•
Bus speed 10.4 kbps nominal
•
Drive capability 32 bus nodes
•
Low RFI due to output waveshaping with adjustable slew rate
•
Direct battery operation with protection against +50V load dump,
jump start and reverse battery
DESCRIPTION
The AU5780A is a line transceiver being primarily intended for
in-vehicle multiplex applications. It provides interfacing between a
link controller and the physical bus wire. The device supports the
SAE/J1850 VPWM standard with a nominal bus speed of 10.4 kbps.
PIN CONFIGURATION
•
Bus terminals proof against automotive transients up to
–200V/+200V
BATT
1
8
GND
•
Thermal overload protection
•
Very low bus idle power consumption
•
Diagnostic loop-back mode
•
4X mode (41.6 kbps) reception capability
•
ESD protected to 9 KV on bus and battery pins
•
8-pin SOIC
TX
2
AU5780A
7
BUS_OUT
R/F
3
6
/LB
RX
4
SO8
5
BUS_IN
SL01207
QUICK REFERENCE DATA
SYMBOL
V
BATT.op
T
A
V
BATT.ld
I
BATT.lp
V
B
V
BOH
–I
BO.LIM
V
BI
t
bo
t
r
, t
f
PARAMETER
Operating supply voltage
Operating ambient temperature
Battery voltage
Bus idle supply current
Bus voltage
Bus output voltage
Bus output source current
Bus input threshold
Delay TX to BUS_OUT, normal battery
BUS_OUT transition times, rise and fall,
normal battery
Measured at 3.875V
Measured between
1.5 V and (V
BATT
– 2.75 V),
9 < V
BATT
< 16 V,
t
r
tested at an additional bus
load of R
LOAD
= 400
W
and
C
LOAD
= 22000 pF
load dump; 1s
V
BATT
=12V
0 < V
BATT
< 24V
300Ω < R
L
< 1.6kΩ
0V < V
BO
< +6.0V
–20
7.3
27
3.65
13
11
CONDITIONS
MIN.
6
–40
TYP.
12
MAX.
24
+125
+50
220
+20
8.0
50
4.1
21
18
UNIT
V
°C
V
µA
V
V
mA
V
µs
µs
ORDERING INFORMATION
DESCRIPTION
SO8: 8-pin plastic small outline package
TEMPERATURE RANGE
–40 to +125°C
ORDER CODE
AU5780AD
DWG #
SOT96-1
2001 Jun 19
2
853-2261 26558
Philips Semiconductors
Product data
SAE/J1850/VPW transceiver
AU5780A
PIN DESCRIPTION
SYMBOL
BATT
TX
R/F
RX
BUS_IN
/LB
BUS_OUT
GND
PIN
1
2
3
4
5
6
7
8
Battery supply input (12V nom.)
Transmit data input; low: transmitter passive; high: transmitter active
Rise/fall slew rate set input
Receive data output; low: active bus condition detected; float/high: passive bus condition detected
Bus line receive input
Loop-back test mode control input; low: loop-back mode; high: normal communication mode
Bus line transmit output
Ground
DESCRIPTION
FUNCTIONAL DESCRIPTION
The AU5780A is an integrated line transceiver IC that interfaces an
SAE/J1850 protocol controller IC to the vehicle’s multiplexed 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 bit rate of 10.4 kbps. The
AU5780A also receives messages in the so-called 4X mode where
data is transmitted with a typical bit rate of 41.6 kbps. 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 AU5780A transceiver waveshapes the
TX data input signal with controlled rise & fall slew rates and
rounded shape. The bus output signal is transmitted with both
voltage and current control. The BUS_IN input is connected to the
physical bus line via an external resistor. The external resistor and
an internal capacitance provides filtering against RF bus noise. The
incoming signal is output at the RX pin being connected to the
J1850 link controller.
If the TX input is idle for a certain time, then the AU5780A enters a
low-power mode. This mode is dedicated to help meet ignition-off
current draw requirements. The BUS_IN input comparator is kept
alive in the low-power mode. Normal power mode will be entered
again upon detection of activity, i.e., rising edge at the TX input. The
device is able to receive and transmit a valid J1850 message when
initially in low-power mode.
The AU5780A features special robustness at its BATT and
BUS_OUT pins hence the device is well suited for applications in
the automotive environment. Specifically, the BATT input is
protected against 50V load dump, jump start and reverse battery
condition. The BUS_OUT output is protected against wiring fault
conditions, e.g., short circuit to battery voltage as well as typical
automotive transients (i.e., –200V / +200V). In addition, an
overtemperature shutdown function with hysteresis is incorporated
which protects the device under system fault conditions. The chip
temperature is sensed at the bus drive transistor in the output buffer.
In case of the chip temperature reaching the trip point, the AU5780A
will latch-off the transceiver function. The device is reset on the first
rising edge on the TX input after a small decrease of the chip
temperature.
The AU5780A also provides a loop-back mode for diagnostic
purpose. If the /LB pin is open circuit or pulled low, then TX signal is
internally looped back to the RX output independent of the signals
on the bus. In this mode the electronic module is disconnected from
the bus, i.e., the TX signal is not output to the physical bus line. In
this mode, it can be used, e.g., for self-test purpose.
The AU5780A is an enhanced successor of the AU5780. The
AU5780A provides improved wave shaping when exiting the low
power standby mode for reduced EMI. Several parameters that
were formerly only characterized to the maximum normal operating
supply of 16 volts, have now been characterized to 24 volt supplies.
These parameters which are tested and guaranteed to 24 volts are
identified with appropriate test conditions in the “conditions” columns
of the Characteristics tables, otherwise the conditions at the top of
the characteristic table applies to all parameters.
2001 Jun 19
4
Philips Semiconductors
Product data
SAE/J1850/VPW transceiver
AU5780A
CONTROL INPUT SUMMARY
TX
0
1
0
1
/LB
0
0
1
1
Loop-back
Loop-back
Communication
Communication
MODE
BIT VALUE
TX passive (default state)
TX active
Transmitter passive
Transmitter active
BUS_OUT
float
float
float
high
RX
(out)
float (high)
low
bus state
1
low
NOTE:
1. RX outputs the bus state. If the bus level is below the receiver threshold (i.e., all transmitters passive), then RX will be floating (i.e., high,
considering external pull-up resistance). Otherwise, if the bus level is above the receiver threshold (i.e., at least one transmitter is active),
then RX will be low.
ABSOLUTE MAXIMUM RATINGS
According to the IEC 134 Absolute Maximum System; operation is not guaranteed under these conditions; all voltages are referenced to pin 8
(GND); positive currents flow into the IC; unless otherwise specified.
SYMBOL
V
BATT
V
BATT.ld
V
BATT.tr1
V
BATT.tr2
V
BATT.tr3
V
B
V
B.tr1
V
B.tr2
V
B.tr3
V
I
ESD
BATT
ESD
bus
ESD
logic
P
tot
Θ
JA
T
amb
T
stg
T
vj
T
LEAD
I
CL(BUS)
I
CL(BATT)
supply voltage
short-term supply voltage
transient supply voltage
transient supply voltage
transient supply voltage
Bus voltage
transient bus voltage
transient bus voltage
transient bus voltage
DC voltage on pins TX, R/F, RX, /LB
ESD capability of BATT pin
ESD capability of BUS_OUT and BUS_IN pins
ESD capability of TX, RX, R/F, and /LB pins
maximum power dissipation
thermal impedance
operating ambient temperature
storage temperature
junction temperature
Lead temperature
Bus output clamp current
Battery clamp current
Soldering, 10 seconds maximum
No latch-up, |V
BUS
| = 25 V
No latch-up or snap back,
|V
BATT
| = 25 V
–40
–40
–40
Air gap discharge,
R=2kΩ, C=150pF
Air gap discharge,
R=2kΩ, C=150pF, R
f
> 10 kW
Human Body,
R=1.5kΩ, C=100pF
at T
amb
= +125
°C
load dump; t < 1s
SAE J1113 pulse 1
SAE J1113 pulses 2
SAE J1113 pulses 3A, 3B
R
f
> 10 kΩ
;
Rb >10Ω
1
SAE J1113 pulse 1
SAE J1113 pulses 2
SAE J1113 pulses 3A, 3B
–200
–0.3
–9
–9
–2
–200
–20
–50
+100
+200
7
+9
+9
+2
164
152
+125
+150
+150
265
100
100
–100
+150
+200
+20
PARAMETER
CONDITIONS
MIN.
–20
MAX.
+24
+50
V
V
V
V
V
V
V
V
V
V
kV
kV
kV
mW
°C/W
°C
°C
°C
°C
mA
mA
UNIT
NOTE:
1. For bus voltages –20V < V
bus
< –17V and +17V < V
bus
< +20V the current is limited by the external resistors R
b
and R
f
.
2001 Jun 19
5
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