SN65HVD485EP

SN65HVD485EP is an integrated circuit designed for interfacing bus systems. The device is designed for two-wire half-duplex communication between any two nodes. The device is designed to be compatible with the existing RS-485 physical layer specification and provides a complete interface between the isolated RS-485 data bus and the pulse code modulated (PCM) data signals generated by microcontrollers, CPUs, or other digital systems. This is an advanced version of the original SN65HVD485E and provides a high speed data link with better noise immunity, lower power consumption and improved signals.

Applications

SN65HVD485EP can be used in many applications requiring communication over short or long distances. The device typically provides a high speed, reliable data link for two-wire half-duplex communication in automotive, industrial and general embedded applications. Due to the built-in protection features, it is suitable for applications that are noise sensitive. In automotive applications, the device is suitable for CAN bus, LIN (Local Interconnect Network) and other serial data applications.

Working Principle

SN65HVD485EP works on a two-wire half-duplex communication principle. This means that only one node can transmit at a time while the receiver is in receive mode. The device has two complementary differential outputs, one for data transmission and the other for data reception. The device also integrates a balanced line transceiver which allows it to drive and receive signals on a balanced line. The device operates according to the CAN protocol, hence there is no central master and data can be exchanged with any node on the bus. The data is serialized before send, and de-serialized after receive in order to reduce the amount of data transmitted.

In order for two nodes on the bus to communicate, the device monitors the bus for activity. When the device detects a valid signal from one node, it informs the second node that it is transmitting and the second node can receive. This is ensured by the special line receivers which allow the device to detect and receive data from the bus. When the transmission is complete, the device notifies the second node that it can start transmitting data on the bus. If the bus is idle, the device will alert both nodes that data transmission can begin.

The device is equipped with various safety features to reduce noise and interference on the bus. It has a driver enable and receiver enable pin which can be used to select the operating mode and enable or disable transmission and reception mode. The device also has a high frequency noise filter which can be activated, reducing noise on the bus.

The device has an integrated line termination circuit which is used to improve signal quality and reduce interference. The device also has an integrated voltage regulator which provides a clean power supply for the IC, ensuring it runs stable and reliable at all times.