TH8080
SoloLIN Transceiver
3. Functional Description
3.1 Initialization
After
power on,
the chip enters automatically the recessive state. If the voltage regulator provides the V
CC
–
supply voltage, normal communication is possible.
3.2 Operating Modes
All operation modes will be handled from the TH8080 automatically.
Normal Mode
After power on, the IC switches automatically to normal mode. Bus communication is possible.
If there is no communication on the bus line the power consumption of the IC is very low and therefore it is
no standby management from the MCU necessary.
Thermal Shutdown Mode
If the junction temperature T
J
is higher than 155°C, the TH8080 will be switched into the thermal shutdown
mode (bus driver will be switched off).
If T
J
falls below the thermal shutdown temperature (typ. 140°C) the TH8080 will be switched to the normal
mode.
3.3 LIN BUS Transceiver
The transceiver consists a bus-driver with slew rate control, current limitation and as well in the receiver a
high voltage comparator followed by a debouncing unit.
BUS Input/Output
The recessive BUS level is generated from the integrated 30k pull up resistor in serial with a diode This
diode prevent the reverse current of V
BUS
during differential voltage between VS and BUS (V
BUS
>V
S
).
No additional termination resistor is necessary to use the TH8080 in LIN slave nodes. If this IC is used for
LIN master nodes it is necessary that the BUS pin is terminated via a external 1k
Ω
resistor in serial with a
diode to VBAT.
TxD Input
During transmission the data at the pin TxD will be transferred to the BUS driver for generating a BUS signal.
To minimize the electromagnetic emission of the bus line, the BUS driver is equipped with an integrated slew
rate control and wave shaping unit.
Transmitting will be interrupted if thermal shutdown is active.
The CMOS compatible input TxD controls directly the BUS level:
TxD = low
TxD = high
->
->
BUS = low (dominant level)
BUS = high (recessive level)
The TxD pin has an internal pull up resistor connected to VCC. This secures that an open TxD pin generates
a recessive BUS level.
TH8080 – Datasheet
3901008080
Page 10 of 23
July 2004
Rev 006
MELEXIS [ Melexis Microelectronic Systems ]
