INTEGRATED CIRCUITS
DATA SHEET
TJA1020
LIN transceiver
Product specification
Supersedes data of 2002 Jul 17
2004 Jan 13
Philips Semiconductors
Product specification
LIN transceiver
FEATURES
General
•
Baud rate up to 20 Kbaud
•
Very low ElectroMagnetic Emission (EME)
•
High ElectroMagnetic Immunity (EMI)
•
Low slope mode for an even further reduction of EME
•
Passive behaviour in unpowered state
•
Input levels compatible with 3.3 and 5 V devices
•
Integrated termination resistor for Local Interconnect
Network (LIN) slave applications
•
Wake-up source recognition (local or remote)
•
Supports K-line like functions.
Low power management
•
Very low current consumption in sleep mode with local
and remote wake-up.
Protections
•
Transmit data (TXD) dominant time-out function
•
Bus terminal and battery pin protected against
transients in the automotive environment (ISO7637)
•
Bus terminal short-circuit proof to battery and ground
•
Thermally protected.
QUICK REFERENCE DATA
SYMBOL
V
BAT
I
BAT
supply voltage on pin BAT
supply current on pin BAT in sleep mode
supply current on pin BAT in standby mode; bus recessive
supply current on pin BAT in normal slope mode; bus recessive
supply current on pin BAT in normal slope mode; bus dominant
V
LIN
T
vj
V
esd(HBM)
DC voltage on pin LIN
virtual junction temperature
electrostatic discharge voltage; human body model;
pins NWAKE, LIN and BAT
PARAMETER
MIN.
5
1
100
100
1
−27
−40
−4
TYP.
12
3
400
400
3.5
−
−
−
GENERAL DESCRIPTION
TJA1020
The TJA1020 is the interface between the LIN
master/slave protocol controller and the physical bus in a
Local Interconnect Network (LIN). It is primarily intended
for in-vehicle sub-networks using baud rates from 2.4 up to
20 Kbaud.
The transmit data stream of the protocol controller at the
TXD input is converted by the LIN transceiver into a bus
signal with controlled slew rate and wave shaping to
minimize EME. The LIN bus output pin is pulled HIGH via
an internal termination resistor. For a master application
an external resistor in series with a diode should be
connected between pin INH or pin BAT and pin LIN. The
receiver detects the data stream at the LIN bus input pin
and transfers it via pin RXD to the microcontroller.
In normal transceiver operation the TJA1020 can be
switched in the normal slope mode or the low slope mode.
In the low slope mode the TJA1020 lengthens the rise and
fall slopes of the LIN bus signal, thus further reducing the
already very low emission in normal slope mode.
In sleep mode the power consumption of the TJA1020 is
very low, whereas in failure modes the power consumption
is reduced to a minimum.
MAX.
27
8
1000
1000
8.0
+40
+150
+4
UNIT
V
µA
µA
µA
mA
V
°C
kV
ORDERING INFORMATION
TYPE
NUMBER
TJA1020T
TJA1020U
PACKAGES
NAME
SO8
−
DESCRIPTION
plastic small outline package; 8 leads; body width 3.9 mm
bare die; die dimensions 1480
×
1760
×
375
µm
VERSION
SOT96-1
−
2004 Jan 13
2
Philips Semiconductors
Product specification
LIN transceiver
BLOCK DIAGRAM
TJA1020
handbook, full pagewidth
BAT
7
WAKE-UP
TIMER
CONTROL
8
INH
NWAKE
3
NSLP
2
SLEEP/
NORMAL
TIMER
TEMPERATURE
PROTECTION
6
LIN
TXD
4
TXD
TIME-OUT
TIMER
TJA1020T
1
RXD/
INT
BUS
TIMER
FILTER
5
GND
RXD
MGU241
Fig.1 Block diagram.
PINNING
SYMBOL
RXD
NSLP
PIN
1
2
DESCRIPTION
receive data output (open-drain);
active LOW after a wake-up event
sleep control input (active LOW);
controls inhibit output; resets
wake-up source flag on TXD and
wake-up request on RXD
local wake-up input (active LOW);
negative edge triggered
transmit data input; active LOW
output after a local wake-up event
ground
LIN bus line input/output
battery supply
battery related inhibit output for con-
trolling an external voltage regulator;
active HIGH after a wake-up event
Fig.2 Pinning diagram.
handbook, halfpage
RXD 1
NSLP 2
8
7
INH
BAT
LIN
GND
NWAKE
TXD
GND
LIN
BAT
INH
3
4
5
6
7
8
TJA1020T
NWAKE 3
TXD 4
MGU242
6
5
2004 Jan 13
3
Philips Semiconductors
Product specification
LIN transceiver
FUNCTIONAL DESCRIPTION
TJA1020
The TJA1020 is the interface between the LIN master/slave protocol controller and the physical bus in a Local
Interconnect Network (LIN). The LIN transceiver is optimized for the maximum specified LIN transmission speed of
20 Kbaud providing optimum EMC performance due to wave shaping of the LIN output.
Operating modes
The TJA1020 provides two modes of normal operation, one intermediate mode and one very low power mode. Figure 3
shows the state diagram.
handbook, full pagewidth
STANDBY
INH = HIGH
TERM. = 30 kΩ
RXD = LOW
trx OFF
t(NSLP = 1; after 0−>1)
>
tgotonorm
while TXD = 1
NORMAL
SLOPE MODE
INH = HIGH
TERM. = 30 kΩ
RXD = LINDATA
trx ON
(t(NWAKE = 0; after 1−>0)
>
tNWAKE
or
t(LIN = 0; after 1−>0)
>
tBUS)
t(NSLP = 1; after 0−>1)
>
tgotonorm
while TXD = 0
t(NSLP = 0; after 1−>0)
>
tgotosleep
while TXD = 1
t(NSLP = 1; after 0−>1)
>
tgotonorm
while TXD = 1
LOW
SLOPE MODE
INH = HIGH
TERM. = 30 kΩ
RXD = LINDATA
trx ON
t(NSLP = 0; after 1−>0)
>
tgotosleep
while TXD = 1
SLEEP
INH = FLOATING
TERM. =
HIGH-OHMIC
RXD = FLOATING
trx OFF
t(NSLP = 1; after 0−>1)
>
tgotonorm
while TXD = 0
switching on BAT
MGU243
trx: transmitter.
TERM.: slave termination resistor, connected between pins LIN and BAT.
Fig.3 State diagram.
2004 Jan 13
4
Philips Semiconductors
Product specification
LIN transceiver
Table 1
MODE
Sleep
Standby
(1)
Operating modes
NSLP
0
0
TXD (OUTPUT)
weak pull-down
RXD
floating
INH
HIGH
TRANSMITTER
off
TJA1020
REMARKS
no wake-up request detected
wake-up request detected; in
this mode the microcontroller
can read the wake-up source:
remote or local wake-up
notes 2, 3 and 4
floating off
weak pull-down if LOW; note 3
remote wake-up;
strong pull-down if
local wake-up;
note 2
weak pull-down
Normal
slope
mode
Low slope
mode
1
HIGH:
HIGH
recessive state
LOW:
dominant state
HIGH:
HIGH
recessive state
LOW:
dominant state
normal slope
mode
1
weak pull-down
low slope mode
notes 2, 3 and 5
Notes
1. The standby mode is entered automatically upon any local or remote wake-up event during sleep mode. Pin INH and
the 30 kΩ termination resistor at pin LIN are switched on.
2. The internal wake-up source flag (set if a local wake-up did occur and fed to pin TXD) will be reset when entering
normal slope or low slope mode (NSLP goes HIGH).
3. The wake-up interrupt (on pin RXD) is released when entering normal slope or low slope mode (NSLP goes HIGH).
4. The normal slope mode is entered during a positive edge on NSLP while pin TXD is already set HIGH. In the event
of a short-circuit to ground on pin TXD, the transmitter will be disabled.
5. The low slope mode is entered during the positive edge on NSLP while pin TXD is already pulled LOW.
Sleep mode
This mode is the most power saving mode of the TJA1020
and the default state after power-up (first battery supply).
Despite its extreme low current consumption, the TJA1020
can still be waken up remotely via pin LIN, or waken up
locally via pin NWAKE, or activated directly via pin NSLP.
Filters at the inputs of the receiver (LIN), of pin NWAKE
and of pin NSLP are preventing unwanted wake-up events
due to automotive transients or EMI. All wake-up events
have to be maintained for a certain time period (t
BUS
,
t
NWAKE
and t
gotonorm
).
The sleep mode is initiated by a falling edge on the pin
NSLP while TXD is already set HIGH. After a filter time
continuously driven sleep command (pin NSLP = LOW),
pin INH becomes floating.
In sleep mode the internal slave termination between
pins LIN and BAT is disabled to minimize the power
dissipation in case pin LIN is short-circuited to ground.
Only a weak pull-up between pins LIN and BAT is present.
The sleep mode can be activated independently from the
actual level on pin LIN or NWAKE. So it is guaranteed that
the lowest power consumption is achievable even in case
of a continuous dominant level on pin LIN or a continuous
LOW on pin NWAKE.
Standby mode
The standby mode is entered automatically whenever a
local or remote wake-up occurs while the TJA1020 is in its
sleep mode. These wake-up events activate pin INH and
enable the slave termination resistor at the pin LIN. As a
result of the HIGH condition on pin INH the voltage
regulator and the microcontroller can be activated.
The standby mode is signalled by a LOW level on pin RXD
which can be used as an interrupt for the microcontroller.
In the standby mode (pin NSLP is still LOW), the condition
of pin TXD (weak pull-down or strong pull-down) indicates
the wake-up source: weak pull-down for a remote wake-up
request and strong pull-down for a local wake-up request.
2004 Jan 13
5
ST Sensors & Low Power Wireless Technology Forum
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