NCV7420
LIN Transceiver with 3.3 V
or 5 V Voltage Regulator
General Description
The NCV7420 is a fully featured local interconnect network (LIN)
transceiver designed to interface between a LIN protocol controller
and the physical bus. The transceiver is implemented in I3T
technology enabling both high−voltage analog circuitry and digital
functionality to co−exist on the same chip.
The NCV7420 LIN device is a member of the in−vehicle
networking (IVN) transceiver family of ON Semiconductor that
integrates a LIN v2.0/2.1 physical transceiver and either a 3.3 V or a
5 V voltage regulator. It is designed to work in harsh automotive
environment and is submitted to the TS16949 qualification flow.
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.
KEY FEATURES
LIN−Bus Transceiver
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PIN CONFIGURATION
V
BB
LIN
GND
GND
WAKE
INH
OTP_ZAP
1
14
V
CC
RxD
TxD
GND
STB
EN
TEST
NCV7420
SOIC 14
D SUFFIX
CASE 751AP
2
3
4
5
6
7
13
12
11
10
9
8
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 19 of this data sheet.
•
LIN compliant to specification revision 2.0 and 2.1
•
•
•
•
•
(backward compatible to version 1.3) and J2602
I3T high voltage technology
Bus voltage
±45
V
Transmission rate up to 20 kBaud
SOIC 14 Green package
This is a Pb−Free Device
Voltage Regulator
•
•
•
•
Output voltage 5 V / ~50 mA or 3.3 V / ~50 mA
Wake−up input
Enable inputs for stand−by and sleep mode
INH output for auxiliary purposes (switching of an
external pull−up or resistive divider towards battery,
control of an external voltage regulator etc.)
Modes
Protection
•
Normal mode: LIN communication in either low (up to
10 kBaud) or normal slope
•
Sleep mode: V
CC
is switched “off” and no
communication on LIN bus
•
Stand−by mode: V
CC
is switched “on” but there is 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.
Quality
•
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
•
System ESD protection level for LIN, WAKE and Vbb
up to
±12
kV
EMI Compatibility
•
Integrated slope control
•
Meets most demanding EMS/EME requirements
•
Automotive Qualification According to AEC−Q100,
Grade 1
©
Semiconductor Components Industries, LLC, 2012
April, 2012
−
Rev. 7
1
Publication Order Number:
NCV7420/D
NCV7420
Table 1. KEY TECHNICAL CHARACTERISTICS
−
3.3 V version
Symbol
Vbb
Parameter
Nominal battery operating voltage (Note 1)
Load dump protection (Note 2)
Ibb_SLP
Vcc_out
(Note 4)
Iout_max
V_wake
Supply current in sleep mode
Regulated Vcc output, Vcc load 1 mA−30 mA
Regulated Vcc output, Vcc load 0 mA−50 mA
Maximum Vcc output current (Note 3)
Operating DC voltage on WAKE pin
Maximum rating voltage on WAKE pin
Tj
Tjunc
Junction thermal shutdown temperature
Operating junction temperature
3.23
3.19
50
0
−45
165
−40
Vbb
45
195
+150
°C
°C
Unit
V
3.30
3.30
Min
5
Typ
12
Max
26
45
20
3.37
3.41
mA
V
mA
V
Unit
V
Table 2. KEY TECHNICAL CHARACTERISTICS
−
5 V version
Symbol
Vbb
Parameter
Nominal battery operating voltage (Note 1)
Load dump protection
Ibb_SLP
Vcc_out
(Note 4)
Iout_max
V_wake
Supply current in sleep mode
Regulated Vcc output, Vcc load 1 mA−30 mA
Regulated Vcc output, Vcc load 0 mA−50 mA
Maximum Vcc output current (Note 3)
Operating DC voltage on WAKE pin
Maximum rating voltage on WAKE pin
Tj
Tjunc
Junction thermal shutdown temperature
Operating junction temperature
4.9
4.83
50
0
−45
165
−40
Vbb
45
195
+150
°C
°C
5.0
5.0
Min
6
Typ
12
Max
26
45
20
5.1
5.17
mA
V
mA
V
1. Below 5 V on VBB in normal mode, the bus will either stay recessive or comply with the voltage level specifications and transition time
specifications as required by SAE J2602. It is ensured by the battery monitoring circuit.
2. The applied transients shall be in accordance with ISO 7637 part 1, test pulse 5. The device complies with functional class C; class A can
be reached depending on the application and external conditions.
3. Thermal aspects of the entire end−application have to be taken into account in order to avoid thermal shutdown of NCV7420.
4. Vcc voltage regulator output must be properly decoupled by external capacitor of min. 8
mF
with ESR < 1
W
to ensure stability.
Table 3. THERMAL CHARACTERISTICS
Symbol
R
th(vj−a)_1
R
th(vj−a)_4
Parameter
Thermal resistance junction−to−ambient on JEDEC 1S0P PCB
Thermal resistance junction−to−ambient on JEDEC 2S2P PCB
Conditions
free air
free air
Value
140
80
Unit
K/W
K/W
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2
NCV7420
V
CC
NCV7420
Band−
gap
V
BB
INH
Osc
V
BB
V−reg
WAKE
V
CC
POR
V
BB
V
CC
STB
Control Logic
EN
Thermal
shutdown
V
BB
V
CC
Stand−by,
Sleep
Normal
mode
RxD
Receiver
LIN
V
CC
TxD
Timeout
Driver &
Slope
Control
TEST
OTP_ZAP
GND
Figure 1. Block Diagram
Typical Application
Application Schematic
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 & Slave), and the required
time constant of the system, respectively.
Vcc voltage must be properly stabilized by external
capacitor: capacitor of min. 8
mF
(ESR < 1
W).
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3
NCV7420
VBAT
10uF 100nF
10uF
Master Node
VBAT
10uF 100nF
V
BB
INH
V
CC
RxD
10uF
Slave Node
V
BB
INH
V
CC
RxD
V
CC
V
CC
1kW
NCV7420
LIN
TxD
EN
STB
TEST
NCV7420
220pF
LIN
1 nF
Micro
controller
LIN
TxD
EN
STB
TEST
LIN
Micro
controller
WAKE
10nF
GND
WAKE
OTP_ZAP
GND
WAKE
10nF
GND
GND
WAKE
OTP_ZAP
GND
GND
KL30
LIN−BUS
KL31
Figure 2. Typical Application Diagram
Table 4. PIN DESCRIPTION
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Name
VBB
LIN
GND
GND
WAKE
INH
OTP_ZAP
TEST
EN
STB
GND
TxD
RxD
Vcc
Battery supply input
LIN bus output/input
Ground
Ground
High voltage digital input pin to switch the part from sleep− to standby mode
Inhibit output
Supply for programming of trimming bits at factory testing, should be grounded in the application
Digital input for factory testing, should be grounded in the application
Enable input, transceiver in normal operation mode when high
Standby mode control input
Ground
Transmit data input, low in dominant state
Receive data output; low in dominant state; push−pull output
Supply voltage (output)
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.
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.
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4
NCV7420
Stand−by mode
Power off
Power up Vbb
Vbb > Vbb_UV_th
−Vcc:
“on”
−LIN
TX: “off”
−Term:
“current source”
−INH:
“floating”
−RxD:
pull−up to Vcc/low
EN goes from 0 to 1 while TxD = 1,
and Vcc > Vcc_UV_th and Vbb > Vbb_UV_th
Normal mode
(normal slope)
−Vcc:
“on”
−LIN
TX: “on”
−Term:
30 kW
−INH:
“high”/“floating”
−RxD:
LIN Data (push−pull)
EN goes from 1 to 0
while STB = 1 or Vbb < Vbb_UV_th
Vbb < PORL_Vbb
and Vcc > Vcc_UV_th, Vbb > Vbb_UV_th
while STB = 1 or Vbb < Vbb_UV_th
Local wake−up
or LIN wake−up
Note:
LIN Transmitter is “off” when
Vbb < Vbb_UV_th
Normal mode
(low slope)
−Vcc:
“on”
−LIN
TX: “on”
−Term:
30 kW
−INH:
“high”/“floating”
−RxD:
LIN data (push−pull)
Sleep mode
EN goes from 1 to 0
while STB = 0 and Vbb > Vbb_UV_th
−Vcc:
“off”
−LIN
TX: “off”
−Term:
“current source”
−INH:
“floating”
−RxD:
pull−up to Vcc
Figure 3. State Diagram
Table 5. MODE SELECTION
Mode
Normal
−
Slope
Normal
−
Low Slope
Stand−by
Sleep
Vcc
ON
ON
ON
OFF
RxD
Low = Dominant State
High = Recessive State
Low = Dominant State
High = Recessive State
Low after LIN wakeup,
high otherwise
Clamped to Vcc
INH
High if STB=High during state
transition; Floating otherwise
High if STB=High during state
transition; Floating otherwise
Floating
Floating
LIN
Normal
Slope
Low Slope
OFF
OFF
30 kW on LIN
ON
ON
OFF
OFF
Note
(Note 5)
(Note 6)
(Notes 7
and 8)
5. The normal slope mode is entered when pin EN goes HIGH while TxD is in HIGH state during EN transition.
6. 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.
7. The stand−by mode is entered automatically after power−up.
8. In Stand−by mode, RxD High state is achieved by internal pull-up resistor to VCC.
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 Vbb (or INH). See Figure 2.
The 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
is done by EN=HIGH when TxD pin is LOW. In order not
to transmit immediately a dominant state on the bus (because
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5
while STB = 0 and Vbb > Vbb_UV_th
from any mode
EN goes from 0 to 1 while TxD = 0,
EN goes from 1 to 0
EN goes from 1 to 0
stm32/stm8
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