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NCV7382

Enhanced LIN Transceiver

ON Semiconductor 

NCV7382

The TxD pin has an internal pullup resistor connected to

VCC. This secures that an open TxD pin generates a

recessive BUS level.

RxD Output

The signal on the BUS pin will be transferred

continuously to the RxD pin. Short spikes on the bus signal

are filtered with internal circuitry (Figure 3 and Figure 7).

VS

BUS

60%

50%

VBUS_CNT_max

VhHYS

40%

VBUS_CNT_min

t

t < trec_deb

t < trec_deb

RxD

t

Figure 7. Receive Impulse Diagram

The receive threshold values VBUS_CNT_max and

VBUS_CNT_min are symmetrical to 0.5 * VS with a

hysteresis of 0.16 * VS (typical). The LIN specific receive

threshold is between 0.4 * VS and 0.6*VS.

The received BUS signal will be output to the RxD pin:

BUS < VBUS_CNT – 0.5 * VHYS

→ RxD = low (BUS dominant)

BUS > VBUS_CNT + 0.5 * VHYS

→ RxD = high, floating (BUS recessive)

RxD is a buffered open drain output with a typical load

of:

Resistance: 2.7 kW

Capacitance: < 20 pF

EN−Pin

The NCV7382 is switched into sleep mode with a falling

edge and into normal mode with a rising edge of the EN pin.

It will remain in normal mode as long as EN = high (See

Figure 4 − Sleep Mode and Wakeup Procedure for more

details).

When the NCV7382 is switched to sleep mode, the

voltage regulator on the INH pin is switched off.

The NCV7382 can be turned off with EN = low

independent of the state of the bus−transceiver.

The EN input has an internal pulled down to guarantee

a low level with EN floating.

Data Rate

The NCV7382 is a constant slew rate transceiver. The

bus driver operates with a fixed slew rate range of 1.0 V/ms

v DV/DT v 3.0 V/ms. This principle provides very good

symmetry of the slope times between recessive to dominant

and dominant to recessive slopes within the LIN bus load

range (CBUS, Rterm).

The NCV7382 guarantees data rates up to 20 kbit within

the complete bus load range under worst case conditions.

The constant slew rate principle holds appropriate voltage

levels and can operate within the LIN Protocol

Specification for RC oscillator systems with a matching

tolerance up to 2%.

Operating Under Disturbance

Loss of Battery

If VS and VCC are disconnected from the battery, the bus

pin is in high impedance state. There is no impact to the bus

traffic.

Loss of Ground

In case of an interrupted ground connection from VS and

VCC, there is no influence to the bus line.

Short Circuit to Battery

The transmitter output current is limited to 200 mA

(max) in case of short circuit to battery.

Short Circuit to Ground

Negative voltages on the BUS pin are limited primarily

to current through the internal 30 k resistor and series diode

from VS through a switched device controlled by EN.

Secondary contributions are attributed to the resistor and

diode hardwired from VS to BUS.

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