TJA1021 LIN收发器解决方案

NXP 公司的TJA1021是LIN 2.0/SAE J2602收发器。它在本地互联网络(LIN)主/从协议控制器和LIN中物理总线间进行接口。它和LIN 2.0/SAE J2602标准兼容，在车内的子网络的波特速率从1 kBd 到 20 kBd。它和TJA1020引脚兼容，并改进了ESD保护性能。本文介绍了TJA1021的主要性能，方框图以及和微控制器间的典型应用电路图。

LIN 2.0/SAE-J2602 standalone transceiver TJA1021
LIN lets you easily interconnect locally applied sensors, actuators and switches (in switch panels, door and seat modules for example) to the CAN backbone with a standardized front end. This helps significantly reduce costs and design-in effort for a wide range of human reaction time triggered applications, such as powered mirrors and windows.

The rapid adoption by automotive makers of the LIN 2.0 protocol has made this cost-effective,low-speed serial communication system bus the natural choice for arbitration-free local communications. Optimized for reliable and cost-effective LIN master and slave node implementations, with its sleep current consumption < 10μA and providing IEC-61000-4-2 compliant ± 6 kV ESD protection, the TJA1021 gives you the leading-edge when creating LIN systems.

The TJA1021 is the interface between the Local Interconnect Network (LIN) master/slave protocol controller and the physical bus in a LIN. It is primarily intended for in-vehicle sub-networks using baud rates from 1 kBd up to 20 kBd and is LIN 2.0/SAE J2602 compliant. The TJA1021 is pin-to-pin compatible with the TJA1020 and improved on ElectroStatic Discharge (ESD).

The transmit data stream of the protocol controller at the transmit data input (TXD) is
converted by the TJA1021 into a bus signal with optimized slew rate and wave shaping to minimize ElectroMagnetic Emission (EME). The LIN bus output pin is pulled HIGH via an internal termination resistor. For a master application an external resistor in series with a diode should be connected between pin INH or pin VBAT and pin LIN. The receiver detects the data stream at the LIN bus input pin and transfers it via pin RXD to the microcontroller.

In sleep mode the power consumption of the TJA1021 is very low. In failure modes the
power consumption is reduced to a minimum.

主要特性：
通用特性
LIN 2.0/SAE J2602 compliant
Baud rate up to 20 kBd
Very low ElectroMagnetic Emission (EME)
High ElectroMagnetic Immunity (EMI)
Passive behavior in unpowered state
Input levels compatible with 3.3 V and 5 V devices
Integrated termination resistor for LIN slave applications
Wake-up source recognition (local or remote)
Supports K-line like functions
Pin-to-pin compatible with TJA1020

低功耗管理
Very low current consumption in sleep mode with local and remote wake-up

保护性能
High ESD robustness: ?6 kV according to IEC 61000-4-2 for pins LIN, VBAT and
WAKE_N
Transmit data (TXD) dominant time-out function
Bus terminal and battery pin protected against transients in the automotive
environment (ISO 7637)
Bus terminal short-circuit proof to battery and ground
Thermally protected

主要优势:
Helps meet car maker’s ESD requirements without the need for external components
Low quiescent current (< 10μA) helps meet more relaxed current consumption targets
Leadless HVSON8 package offers 60% board space reduction compared to SO8
Fail-safe features allowing easier design-in
Easily interfaces with a wide range of microcontrollers
Zero reverse bus current allows partial networking without introducing extra network design complexity
Drop-in replacement for TJA1020

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图1。TJA1021方框图

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图2。TJA1021典型应用电路图（1）

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图3。TJA1021典型应用电路图（2）