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NCV7382

Enhanced LIN Transceiver

ON Semiconductor 

NCV7382

Functional Description

Initialization

After power on, the chip automatically enters the

VBAT−standby mode. In this intermediate mode the INH

output will become HIGH (VS) and therefore the ECU −

voltage regulator will provide the VCC−supply. The

transceiver will remain in the VBAT standby mode until the

controller sets it to normal operation (EN = High). Bus

communication is only possible in normal mode. The

NCV7382 switches itself to the VBAT−standby mode if VCC

is missing or below the undervoltage lockout threshold.

Operating Modes

The EN pin is used to switch the NCV7382 into different

operating modes.

Normal Mode

All of the NCV7382 is active. Switching to normal mode

can only be done with EN = high.

Sleep Mode

The sleep mode (EN = LOW) can only be reached from

normal mode and permits a very low power consumption

because the transceiver and the external voltage regulator

are disabled. If VCC has been switched off, a wakeup

request from the bus line (remote wakeup) will cause the

NCV7382 to enter the VBAT−standby mode (VCC is present

again) and sets the RxD output to low until the device enters

the normal operation mode (active LOW interrupt at RxD).

If the INH pin is not connected to the regulator or the

inhibitable external regulator is not the one that provides

the VCC − supply, the normal mode is directly accessible by

logic high on the EN pin. (Wakeup via mode change/local

wakeup.)

In order to prevent an unintended wakeup caused by

disturbances in the automotive environment, incoming

dominant signals from the bus have to exceed the wakeup

delay time.

Thermal Shutdown Mode

If the junction temperature TJ is higher than 155°C, the

NCV7382 could be switched into the thermal shutdown

mode. Transmitter will be switched off.

If TJ falls below the thermal shutdown temperature (typ.

140°C), the NCV7382 will be switched to the previous

state.

Table 1. Mode Control

EN

VCC

0

0

0

1

1

1

0

0

0

1

0

0/1

Comment

VBAT−standby, Power On

VBAT−standby, VCC On

Normal Mode

Sleep Mode

Sleep Mode

Regulator not disabled

Directly switch to normal mode with EN = 1

Remote wakeup request

INH

Vs

Vs

Vs

Floating

Floating

Vs

RxD

0

X

VCC = Recessive

0 = Dominant

0

VCC

0 − Active low wakeup

interrupt

LIN BUS Transceiver

The transceiver consists of a bus−driver (1.2 V @

40 mA) with slew rate control, current limit, and a receiver

with a high voltage comparator with filter circuitry.

BUS Input/Output

The recessive BUS level is generated from the integrated

30 k pullup resistor in series with a diode. The diode

prevents the reverse current on VBUS when VBUS > VS.

No additional termination resistor is necessary to use the

NCV7382 on LIN slave nodes. If this IC is used for LIN

master nodes, it is necessary to terminate the bus with

an external 1.0 kW resistor in series with a diode to VBAT

or INH (See Section Short Circuit to Ground).

TxD Input

During transmission the signal on 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 has integrated slew rate control and wave

shaping.

Transmitting will be interrupted in the following cases:

• Sleep Mode

• Thermal Shutdown

• VBAT−standby

The CMOS compatible input TxD directly controls the

BUS level:

TxD = low → BUS = low (dominant level)

TxD = high → BUS = high (recessive level)

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