基于TJA1054設計的汽車CAN收發技術

TJA1054是控制器局部網（CAN）中的協議控制器和物理總線間的接口器件，提供差分接收和發送功能，波特速率高達125kBd,可連接高達32個節點，支持未屏蔽的總線連接，有非常低的電磁輻射（EME）和非常高的電磁干擾（EMI）免疫力，并集成了接收濾波器。

TJA1054主要特性和優勢：

Optimized for in-car low-speed communication

Baud rate up to 125 kBd

Up to 32 nodes can be connected

Supports unshielded bus wires

Very low ElectroMagnetic Emission (EME) due to built-in slope control function and a
very good matching of the CANL and CANH bus outputs

Very high ElectroMagnetic Immunity (EMI) in normal and low power operating modes

Fully integrated receiver filters

Transmit Data (TxD) dominant time-out function

Bus failure management

Supports single-wire transmission modes with ground offset voltages up to 1.5 V

Automatic switching to single-wire mode in the event of bus failures, even when the CANH bus wire is short-circuited to VCC

Automatic reset to differential mode if bus failure is removed

Full wake-up capability during failure modes

Protections

Bus pins short-circuit safe to battery and to ground

Thermally protected

Bus lines protected against transients in an automotive environment

An unpowered node does not disturb the bus lines

Support for low power modes

Low current sleep mode and standby mode with wake-up via the bus lines

Power-on reset flag on the output

圖1。TJA1054方框圖

圖2。TJA1054動態特性測試電路圖