NCV7420

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4

Figure 2. Typical Application Diagram

KL30

LIN−BUS

KL31

LIN

Master Node

GND

Micro

controller

GND

INH

VBAT

GND

WAKE

LIN

Slave Node

GND

Micro

controller

VBAT

GND

WAKE

10uF

10uF 100nF

TEST

OTP_ZAP

GND

INH

TEST

OTP_ZAP

LIN

WAKE

10uF 100nF

LIN

WAKE

EN

STB

TxD

RxD

EN

STB

TxD

RxD

10uF

Table 4. PIN DESCRIPTION

Pin

Name

Description

1

VBB

Battery supply input

2

LIN

LIN bus output/input

3

GND

Ground

4

GND

Ground

5

WAKE

High voltage digital input pin to switch the part from sleep− to standby mode

6

INH

Inhibit output

7

OTP_ZAP

Supply for programming of trimming bits at factory testing, should be grounded in the application

8

TEST

Digital input for factory testing, should be grounded in the application

9

EN

Enable input, transceiver in normal operation mode when high

10

STB

Standby mode control input

11

GND

Ground

12

TxD

Transmit data input, low in dominant state

13

RxD

Receive data output; low in dominant state; push−pull output

14

Vcc

Supply voltage (output)

Overall Functional Description

LIN is a serial communication protocol that efficiently

supports the control of mechatronic nodes in distributed

automotive applications. The domain is class−A multiplex

buses with a single master node and a set of slave nodes.

NCV7420 is designed as a master or slave node for the

LIN communication interface with an integrated 3.3 V or

5 V voltage regulator having a current capability up to

50 mA

for

supplying

any

external

components

(microcontroller).

NCV7420 contains the LIN transmitter, LIN receiver,

voltage regulator, power−on−reset (POR) circuits and

thermal shutdown (TSD). The LIN transmitter is optimized

for the maximum specified transmission speed of 20 kBaud

with EMC performance due to reduced slew rate of the LIN

output.

The junction temperature is monitored via a thermal

shutdown circuit that switches the LIN transmitter and

voltage regulator off when temperature exceeds the TSD

trigger level.

NCV7420 has four operating states (normal mode, low

slope mode, stand−by mode, and sleep mode) that are

determined by the input signals EN, WAKE, STB, and TxD.

Operating States

NCV7420 provides four operating states, two modes for

normal operation with communication, one stand-by

without communication and one low power mode with very

low current consumption. See Figure 3.