Semiconductor NCV7425 Instruction manual

NCV7425

LIN Transceiver with
Voltage Regulator and
Reset Pin

General Description

The NCV7425 is a fully featured local interconnect network (LIN)
transceiver designed to interface between a LIN protocol controller
and the physical bus.

The NCV7425 LIN device is a member of the in−vehicle
networking (IVN) transceiver family of ON Semiconductor that
integrates a LIN v2.1 physical transceiver and a low−drop voltage
regulator.

The LIN bus is designed to communicate low rate data from control
devices such as door locks, mirrors, car seats, and sunroofs at the
lowest possible cost. The bus is designed to eliminate as much wiring
as possible and is implemented using a single wire in each node. Each
node has a slave MCU−state machine that recognizes and translates
the instructions specific to that function. The main attraction of the
LIN bus is that all the functions are not time critical and usually relate
to passenger comfort.

Features

• LIN−Bus Transceiver

♦ LIN compliant to specification revision 2.1

(backward compatible to versions 2.0 and 1.3) and
J2602

♦ Bus Voltage ±45 V
♦ Transmission Rate up to 20 kBaud
♦ Integrated Slope Control for Improved EMI

Compatibility

• Modes

• Package

♦ SOIC−16 Wide Body Package with Exposed Pad

• Protection

♦ Thermal Shutdown
♦ Indefinite Short−Circuit Protection on Pins LIN and

WAKE Towards Supply and Ground

♦ Load Dump Protection (45 V)
♦ Bus Pins Protected Against Transients in an

Automotive Environment

♦ ESD Protection Level for LIN, INH, WAKE and

up to ±10 kV

V

BB

• Voltage Regulator

♦ Two Device Versions: Output Voltage 3.3 V or 5 V

For Loads up to 150 mA

♦ Undervoltage Detector with a Reset Output to the

Supplied Microcontroller

♦ INH Output for Auxiliary Purposes (switching of an

external pull−up or resistive divider towards battery,
control of an external voltage regulator etc.)

Quality

• NCV Prefix for Automotive and Other Applications

Requiring Unique Site and Control Change
Requirements; AEC−Q100 Qualified and PPAP
Capable

• These Devices are Pb−Free, Halogen Free/BFR Free

and are RoHS Compliant

Typical Applications

• Automotive

• Industrial Networks

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MARKING
DIAGRAM

16

SOIC−16 LEAD

WIDE BODY

16

1

See detailed ordering and shipping information in the
package dimensions section on page 19 of this data sheet.

♦ Normal Mode: LIN Communication in Either Low

EXPOSED PAD

CASE 751AG

x = 0 or 5
A = Assembly Location
WL = Wafer Lot
YY = Year
WW = Work Week
G = Pb−Free Package

ORDERING INFORMATION

NCV7425−x

AWLYYWWG

1

(up to 10 kBaud) or Normal Slope

♦ Sleep Mode: V

is Switched “off” and No

CC

Communication on LIN Bus

♦ Standby Mode: V

is Switched “on” but There is

CC

No Communication on LIN Bus

♦ Wake−up Bringing the Component From Sleep

Mode Into Standby Mode is Possible Either by LIN
Command or Digital Input Signal on WAKE Pin
Wake−up from LIN Bus can also be Detected and
Flagged When the Chip is Already in Standby Mode

© Semiconductor Components Industries, LLC, 2015

May, 2015 − Rev. 3

1 Publication Order Number:

NCV7425/D

NCV7425

Table 1. KEY TECHNICAL CHARACTERISTICS

Symbol Parameter Min Typ Max Unit

3.3 V VERSION

V

BB

V

BB

IBB_SLP Supply current in sleep mode 20

V

CC_OUT

(Note 2)

I

OUT_LIM

V

WAKE

V

INH

T

J_TSD

T

J

5 V VERSION

V

BB

V

BB

I

BB_SLP

V

CC_OUT

(Note 2)

I

OUT_LIM

V

WAKE

V

INH

T

J_TSD

T

J

1. The applied transients shall be in accordance with ISO 7637 part 1, test pulse 5. The device complies with functional class C;. The LIN

communication itself complies with functional class B. On regulator class A can be reached depending on the application and external
components

voltage must be properly stabilized by external capacitors: capacitor of min. 80 nF with ESR < 10 mW in parallel with a capacitor of min.

2. V

CC

8 mF, ESR < 1 W.

Nominal battery operating voltage 5 12 28 V
Load dump protection (Note 1) 45 V

mA

Regulated VCC output in normal mode, VCC load 0−100 mA 3.234 3.3 3.366

V
Regulated VCC output in normal mode, 100 mA < VCC load < 150 mA 3.201 3.3 3.399
VCC regulator current limitation 150 225 300 mA
Operating DC voltage on WAKE pin 0 V

BB

V
Maximum rating voltage on WAKE pin −45 45
Operating DC voltage on INH pin 0 V

BB

V
Junction thermal shutdown temperature 165 195 °C
Operating junction temperature −40 +150 °C

Nominal battery operating voltage 6 12 28 V
Load dump protection (Note 1) 45 V
Supply current in sleep mode 20

mA
Regulated VCC output in normal mode, VCC load 0−100 mA 4.90 5 5.10 V
Regulated VCC output in normal mode, 100 mA < VCC load < 150 mA 4.85 5 5.15 V
VCC regulator current limitation 150 225 300 mA
Operating DC voltage on WAKE pin 0 V

BB

V
Maximum rating voltage on WAKE pin −45 45
Operating DC voltage on INH pin 0 V

BB

V
Junction thermal shutdown temperature 165 195 °C
Operating junction temperature −40 +150 °C

Table 2. THERMAL CHARACTERISTICS

Symbol Parameter Conditions Value Unit

R

th(vj−a)_1

R

th(vj−a)_2

R

th(vj−a)_3

R

th(vj−a)_4

Thermal resistance junction−to−ambient on JEDEC 1S0P PCB Free Air 138 K/W
Thermal resistance junction−to−ambient on JEDEC 1S0P + 300 mm2 PCB Free Air 94 K/W

Thermal resistance junction−to−ambient on JEDEC 2S2P PCB Free Air 70 K/W
Thermal resistance junction−to−ambient on JEDEC 2S2P + 300 mm2 PCB Free Air 49 K/W

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2

NCV7425

WAKE

STB

EN

TxD

RxD

RSTN

V

CC

NCV7425

V−reg

V

CC

Control Logic

V

CC

V

CC

V

CC

Timeout

TEST

OTP_ZAP

Figure 1. Block Diagram

Band−

gap

V

shutdown

Receiver

Slope

Control

BB

POR

Thermal

Osc

PD20090609.1

INH

V

BB

V

CC

V

BB

LIN

GND

TYPICAL APPLICATION

Application Information

The EMC immunity of the Master−mode device can be
further enhanced by adding a capacitor between the LIN
output and ground. The optimum value of this capacitor is
determined by the length and capacitance of the LIN bus, the
number and capacitance of Slave devices, the pull−up
resistance of all devices (Master and Slave), and the required
time constant of the system, respectively.

VBAT

WAKE

GND

10uF 100nF

V

BB

INH

LIN

10nF

LIN

1nF 1kW

WAKE

10uF

V

CC V

RxD

TxD

EN

NCV7425

STB

RSTN

TESTOTP_ZAP

GND

KL30

LIN−BUS

KL31

100nF

Master Node

CC

Micro

controller

GND

V

voltage must be properly stabilized by external

CC

capacitors: capacitor of min. 80 nF (ESR < 10 mW) in
parallel with a capacitor of min. 8 mF (ESR < 1 W).

The 10 mF capacitor on the battery is optional and serves
as reservoir capacitor to deal with battery supply
micro−cuts.

VBAT

WAKE

LIN

GND

10nF

10uF 100nF10uF 100nF

V

BBVCC

RxD

INH

TxD

GND

EN

STB

RSTN

TESTOTP_ZAP

LIN

220pF

WAKE

Slave Node

V

Micro

controller

PD20090609.2

CC

GND

Figure 2. Application Diagram

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3

NCV7425

V

LIN
GND
GND

WAKE

INH

OTP_SUP

n.c.

1

BB

2
3
4
5
6
7
8

NCV7425

V

16

CC

15

RxD
TxD

14

RSTN

13

STB

12

EN

11

TEST

10

n.c.

9

Figure 3. Pin Assignment

Table 3. PIN FUNCTION DESCRIPTION

Pin Number Pin Name Description

1 V

BB

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_SUP Supply for programming of trimming bits at factory testing, needs to be grounded in the application
8 n.c. not connected

9 n.c. not connected
10 TEST Digital input for factory testing, needs to be grounded in the application
11 EN Enable input for mode control
12 STB Standby mode control input
13 RSTN Reset output; open−drain output with an on−chip pull−up resistor
14 TxD Transmit data input, Low in dominant state
15 RxD Receive data output; Low in dominant state; push−pull output
16 V

CC

Battery supply input

Voltage regulator output

FUNCTIONAL DESCRIPTION

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.

NCV7425 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
150 mA for supplying any external components
(microcontroller, CAN node, etc.).

NCV7425 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

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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.

NCV7425 has four operating states (normal mode, low
slope mode, standby mode, and sleep mode) that are
determined by the input signals EN, WAKE, STB, and TxD.

Operating States

NCV7425 provides four operating states, two modes for
normal operation with communication, one standby without
communication and one low power mode with very low
current consumption − see Figure 4 and Table 4.

4

NCV7425

Table 4. MODE SELECTION

LIN

Mode V

Normal −

Slope (Note 3)

CC

ON Low = Dominant State

High = Recessive State

RxD INH

High if STB = High
during state transition;
Floating otherwise

Normal − Low

Slope (Note 4)

ON Low = Dominant State

High = Recessive State

High if STB = High
during state transition;
Floating otherwise

Standby
(Note 5)

ON Low after LIN

wake−up, High

Floating OFF OFF Controlled by V

otherwise (Note 6)

Sleep OFF Clamped to V

(Note 6)

CC

Floating OFF OFF Low

3. The normal slope mode is entered when pin EN goes High while TxD is in High state during EN transition.

4. The low slope mode is entered when pin EN goes High while TxD is in Low state during EN transition. LIN transmitter gets on only after TxD
returns to High after the state transition.

5. The standby mode is entered automatically after power−up.

6. In standby and Sleep mode, the High state is achieved by internal pull−up resistor to V

Transceiver

30 kW on LIN

RSTN

Normal Slope ON High

Low Slope ON High

undervoltage

monitor

.

CC

CC

VBB power−up

Standby mode

−

VCC: on

−LIN TRX: off

−INH: floating

−LIN term.: current source

−RxD pin: High/Low

−RSTN pin:

V

CC_UV

undervoltage

CC

ENchanges 0−>1 while TxD=0

V

EN changes 1−>0 while STB=1

Normal mode

(low slope )

: on

V

−

CC

−LIN TRX: on

−INH: High/floating

−LIN term.: 30kW

−RxD pin: LIN data

−RSTN pin: High

EN changes 0−>1while TxD=1

EN changes 1−>0 while STB=1

VCC undervoltage

EN changes 1−>0 while STB=0

Figure 4. State Diagram

Normal mode

(normal slope )

V

: on

−

CC

−LIN TRX: on

−INH: High/floating

−LIN term.: 30kW

−RxD pin: LIN data

−RSTN pin: High

EN changes 1−>0 while STB=0

Sleep mode

−

VCC: off

−LIN TRX: off

−INH: floating

−LIN term.: current source

−RxD pin:

−RSTN pin: Low

at V

CC

PD20090610.01

Normal Slope Mode

In normal slope mode the transceiver can transmit and
receive data via LIN bus with speed up to 20 kBaud. The
transmit data stream of the LIN protocol is present on the
TxD pin and converted by the transmitter into a LIN bus
signal with controlled slew rate to minimize EMC emission.
The receiver consists of the comparator that has a threshold
with hysteresis in respect to the supply voltage and an input
filter to remove bus noise. The LIN output is pulled High via
an internal 30 kW pull−up resistor. For master applications
it is needed to put an external 1 kW resistor with a serial
diode between LIN and V

(or INH) − see Figure 2. The

BB

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mode selection is done by EN=High when TxD pin is High.
If STB pin is High during the standby−to−normal slope
mode transition, INH pin is pulled High. Otherwise, it stays
floating.

Low Slope Mode

In low slope mode the slew rate of the signal on the LIN
bus is reduced (rising and falling edges of the LIN bus signal
are longer). This further reduces the EMC emission. As a
consequence the maximum speed on the LIN bus is reduced
up to 10 kBaud. This mode is suited for applications where
the communication speed is not critical. The mode selection

5

NCV7425

is done by EN=High when TxD pin is Low. In order not to
transmit immediately a dominant state on the bus (because
TxD = Low), the LIN transmitter is enabled only after TxD
returns to High. If STB pin is High during the
standby−to−low slope mode transition, INH pin is pulled
High. Otherwise, it stays floating.

Standby Mode

The standby mode is always entered after power−up of the
NCV7425. It can also be entered from normal mode when
the EN pin is Low and the standby pin is High. From sleep
mode it can be entered after a local wake−up or LIN
wake−up. In standby mode the V

voltage regulator for

CC

supplying external components (e.g. a microcontroller)
stays active. Also the LIN receiver stays active to be able to
detect a remote wake−up via bus. The LIN transmitter is
disabled and the slave internal termination resistor of 30 kW
between LIN and V

is disconnected in order to minimize

BB

current consumption. Only a pull−up current source
between V

and LIN is active.

BB

Wake

V

BB

Detection of Local Wake−Up

50% V

BB

Sleep Mode

The Sleep Mode provides extremely low current
consumption. This mode is entered when both EN and STB
pins are Low coming from normal mode. The internal
termination resistor of 30 kW between LIN and VBB is
disconnected and also the V

regulator is switched off to

CC

minimize current consumption.

Wake−up

NCV7425 has two possibilities to wake−up from sleep or
standby mode (see Figure 4):

Local wake−up: enables the transition from sleep mode to
standby mode

Remote wake−up via LIN: enables the transition from
sleep to standby mode and can be also detected when already
in standby mode.

A local wake−up is only detected in sleep mode if a
transition from Low to High or from High to Low is seen on
the WAKE pin.

Detection of Local Wake−Up

50% VBB typ.

typ.

Wake

V

BB

Sleep Mode Standby Mode

Figure 5. Local Wake−Up Signal

A remote wake−up is only detected if a combination of (1)

a falling edge at the LIN pin (transition from recessive to
dominant) is followed by (2) a dominant level maintained

LIN

Detection of Remote Wake−Up

V

BB

t

WAKE

40% V

BB

Sleep Mode

Figure 6. Remote Wake−Up Behavior

The wake−up source is distinguished by pin RxD in the

standby mode:

RxD remains High after power−up or local wake−up.
RxD is kept Low until normal mode is entered after a

remote wake−up (LIN)

t

Sleep Mode Standby Mode

for a time period > t

WAKE

PC20060427.3

and (3) again a rising edge at pin

t

LIN (transition from dominant to recessive) happens.

LIN recessive level

60% V

BB

LIN dominant level

Standby Mode

VCC Undervoltage Detection and RSTN Pin

t

PC20060427.2

In standby, normal and low slope modes, the V
regulator is monitored. Whenever the regulator output falls
below V

CC_UV_THR

voltage) for longer than V

level (typically 90% of the nominal

CC_UV_deb

(typically 5 ms), an

CC

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6

NCV7425

undervoltage is detected. Output pin RSTN is pulled to Low
level to indicate the undervoltage condition to the external
load (a microcontroller). At the same time, the device enters
automatically the standby mode. As soon as the regulator
output returns above the undervoltage level, the RSTN Low
level is extended by typically 6ms and only then released to
High level in order to ensure microcontroller initialization
under correct supply conditions.

POR

VBB

VCC

RSTN

EN

STB

H_VBB

V

CC_UV_THR

CC_UV_deb

V

RSTN

CC_UV_debVCC_UV_deb

V

ext

STB and EN levels discarded when RSTN=Low

In the sleep mode, RSTN pin is kept Low regardless the
V

level − it means that RSTN becomes Low immediately

CC

at sleep mode entry even if the V

capacitor is still charged.

CC

In all situations where RSTN pin is kept Low, the digital
inputs to NCV7425 are discarded by the internal control
logic and have no effect on its behavior.

The RSTN pin function is illustrated in Figure 7.

< V

CC_UV_deb

ext

RSTN

Standby mode Normal mode Sleep modeNormal modeStandby mode

FB20130807.01

Figure 7. RSTN Pin Behavior

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