NCV7381: Single FlexRay Bus Driver Solution

On Semi’s NCV7381 is a single-channel FlexRay bus driver, compatible with FlexRay electrical physical layer index Rev.3.0.1, with a communication speed of up to 10Mbps, providing a differential communication medium in wired FlexRay communication, with better EMC and ESD performance , working temperature -40 ℃ ~ +125 ℃, in line with automotive-grade quality standards.

The NCV7381 is a single-channel FlexRay bus driver that is compatible with the FlexRay Electrical Physical Layer Specification 3.0.1 and can communicate at speeds up to 10Mbit/s. It has differential transmit and receive capabilities (between wired FlexRay communication media, and between the protocol Controller and the host). The NCV7381 mode control function is optimized for use with nodes where the car battery is permanently connected. It provides excellent EMC and ESD performance.

NCV7381: Single FlexRay Bus Driver Solution

Figure 1 Block diagram of NCV7381

Main features of NCV7381

• Compatible with FlexRay Electrical Physical Layer Specification Revision 3.0.1

• FlexRay transmitter and receiver communicate in normal power mode, up to 10Mbits/s

• Supports 60ns bit time

• FlexRay low-power mode receiver for remote wake-up detection

• Excellent Electromagnetic Susceptibility (EMS) levels, very low Electromagnetic Emissions (EME) over the full frequency range

• Bus pin protection >10kV system ESD pulses

• Safe operation in the absence or absence of power

• Interface pins for protocol controller and host (TXD, RXD, TXEN, RXEN, STBN, BGE, EN, ERRN)

• INH output for external regulator control

• Local wake-up pin WAKE

• TxEn aborts the connection

• BGE feedback

• Power supply pins VBAT, VCC, VIO with independent voltage ramps:

– The parameters of the VBAT power supply range from 5.5V to 50V

– VCC power supply parameters range from 4.75V to 5.25V

– The parameters of VIO power supply range from 2.3V to 5.25V

• Compatible with 14 V and 28 V systems

• Working ambient temperature -40℃~+125℃ (TAMB_Class1)

• Two levels of junction temperature monitoring

• SSOP-16 package

• FlexRay functional classes

• Bus driver voltage regulator control

• Bus Driver-Bus Monitor Interface

• Bus driver logic adaptation

• Bus driver supports remote wakeup

• Compliant with AEC-Q100
NCV7381: Single FlexRay Bus Driver Solution
Figure 2 NCV7381 application block diagram
NCV7381: Single FlexRay Bus Driver Solution
Figure 3 NCV7381 FlexRay bus driver application circuit diagram

NCV7381 APP V2 Evaluation Board

The NCV7381 is a single-channel electrical physical layer bus driver, compatible with FlexRay FlexRay Specification 3.0.1, and its communication speed can reach 10Mbits/s. It can provide differential transmit and receive functions between the wired communication medium on one side, and between the protocol controller and the host FlexRay on the other side. The NCV7381 mode control function is optimized for nodes connected to the car battery.

The NCV7381_APP_V2 evaluation node is a reference design for a standalone 2-channel FlexRay. It allows designers to quickly and easily evaluate the NCV7381 FlexRay bus driver. The design incorporates a complete node solution with a small footprint that can be modified.

A set of two evaluation boards allows users to start using the NCV7381 FlexRay bus driver immediately. Its MCU is pre-programmed firmware that provides simple mode control and FlexRay communication. Using the Freescale BDM programmer, coupled with a suitable development environment, the MCU firmware can be freely modified and reprogrammed.

The evaluation board hardware includes an MCU and an integrated 2-channel FlexRay communication controller interconnected with two independent FlexRay bus drivers (NCV7381), two switchable voltage regulators and peripherals. The board can be modified for various power and FlexRay bus terminations, allowing for simple system expansion without using MCU pins. The USB interface is compatible with standard PCs. Its address switch makes it easy to modify the address of each board, so that complex FlexRay networks can be created without reprogramming the MCU.

Its high-speed CAN interface can be used as a network diagnostic interface for the construction of several nodes. For evaluation, several LED diodes are also assembled on the NCV7381 board, and most of the bus driver’s signal can easily enter the oscilloscope probe.

NCV73812037EVB Evaluation Board Key Features

• FlexRay transceiver

– Two channel, NCV7381 bus driver compliant with FlexRay Separate FlexRay Electrical Physical Layer Specification Revision 3.0.1

– Reconfigurable bus termination – terminal node/intermediate node

– Common mode choke and additional ESD protection

– SUBD-9 connector – FlexRay bus

– Local wake-up switch


– Freescale 16-bit MC9S12XF series MCU

– Integrated FlexRay communication controller (protocol specification version 2.1)

– Integrated CAN2.0 A, B controller

– Background debugging MODUL-Single Wire Communication and Host Development System

– 512kB Flash

– 32kB RAM

– 50MHz maximum CPU bus frequency

– Relatively small 112-pin LQFP package

• Peripherals

– Optically isolated USB interface (USB to UART converter)

– additional CAN interface

– All NCV7381 digital I/O pins are connected to test points for easy connection to logic analyzers

– 8 general purpose LED indicators

– address switch


– Automotive voltage regulator with suppression (input battery voltage up to 42V)

Figure 4 Block diagram of NCV7381 APP V2 evaluation board

– Supply voltage monitoring

– Instant 2-node FlexRay network communication connecting two NCV7381 EVBS

– PC configuration software (on request) PCB layout

– FlexRay transceiver placed near FlexRay ECU, ESD protected common mode choke


– FlexRay signal lines (BP, BM) and interference decoupling on the ECU board

– FlexRay line routing (BP, BM, TX and TXEN) symmetrical

– Distance between BP and BM RESP, TX and TXEN are minimized

For details, see:


The Links:   LP104V2-B1 1DI300ZN-120

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