什么是CAN收发器？

CAN收发器在整个CAN网络中所处的位置如上图所示。CAN收发器就是一块类似232或485的转换芯片，它的主要功能是将CAN控制器的TTL信号转换成CAN总线的差分信号。

CAN是控制器区域网络(Controller Area Network)的缩写，代表将“智能"设备以及同一系统或子系统内的传感器和执行器等连成网络而特别开发的串行总线系统。

根据控制器的CAN接口电压可选择3.3V或5V供电的CAN模块，隔离CAN模块正常输入范围为VCC±5%，主要考虑CAN总线电平能保持在典型值范围内，同时也使次级的CAN芯片工作在标称电源电压附近。

对于单独的CAN收发芯片，需要对芯片的VIO引脚接入与TXD信号电平相同的参考电压，以匹配信号电平，若没有VIO引脚，则应保持信号电平与VCC保持一致。使用CTM系列隔离收发器时需要匹配TXD的信号电平与供电电压一致，即3.3V标准CAN控制器接口或5V标准CAN控制器接口。

传输特性

CAN收发器的传输特性主要为三个参数：发送延迟、接收延迟、循环延迟。

The WT1040/WT1050 is the interface between the Controller Area Network (CAN) protocol controller and the physical bus, and can be applied to the fields of trucks, buses, cars, industrial control etc. It is primarily intended for high speed applications, up to 1 MBaud, in passenger cars. The device provides differential transmit capability to the bus and differential receive capability to the CAN controller, and fully compatible with the ISO 11898 standard.

Fully compatible with the ISO 11898 standard

Thermally protected；
Input levels compatible with 3.3 V and 5 V devices；
Transmit Data (TXD) dominant time-out function；
Very low-current standby mode with remote wake-up capability via the bus（TYP. 5uA）（WT1040)；
Silent mode in which the transmitter is disabled（WT1050)；
Transceiver in unpowered state disengages from the bus (zero load)；
At least 110 nodes can be connected；
High speed (up to 1 MBaud)；
Very low Electro Magnetic Emission (EME)；