SN65HVD21中文资料扩展共模 RS-485 收发器数据手册TI规格书

描述 Description

The transceivers in the SN65HVD2x family offer performance far exceeding typical RS-485 devices. In addition to meeting all requirements of the TIA/EIA-485-A standard. The SN65HVD2x family operates over an extended range of common-mode voltages and has features such as high ESD protection, wide receiver hysteresis, and failsafe operation. This family of devices is ideally suited for long-cable networks and other applications where the environment is too harsh for ordinary transceivers.

These devices are designed for bidirectional data transmission on multipoint twisted-pair cables. Example applications are digital motor controllers, remote sensors and terminals, industrial process control, security stations, and environmental control systems.

These devices combine a 3-state differential driver and a differential receiver that operate from a single 5-V power supply. The driver differential outputs and the receiver differential inputs are connected internally to form a differential bus port that offers minimum loading to the bus. This port features an extended common-mode voltage range, making the device suitable for multipoint applications over long cable runs.

The SN65HVD20 device provides high signaling rate (up to 25 Mbps) for interconnecting networks of up to 64 nodes.

The SN65HVD21 device allows up to 256 connected nodes at moderate data rates (up to 5 Mbps). The driver output slew rate is controlled to provide reliable switching with shaped transitions which reduce high-frequency noise emissions.

The SN65HVD22 device has controlled driver output slew rate for low radiated noise in emission-sensitive applications and for improved signal quality with long stubs. Up to 256 SN65HVD22 nodes can be connected at signaling rates up to 500 kbps.

The SN65HVD23 device implements receiver equalization technology for improved jitter performance on differential bus applications with data rates up to 25 Mbps at cable lengths up to 160 meters.

The SN65HVD24 device implements receiver equalization technology for improved jitter performance on differential bus applications with data rates from 1 Mbps to 10 Mbps at cable lengths up to 1000 meters.

The receivers include a failsafe circuit that provides a high-level output within 250 microseconds after loss of the input signal. The most common causes of signal loss are disconnected cables, shorted lines, or the absence of any active transmitters on the bus. This feature prevents noise from being received as valid data under these fault conditions. This feature may be used for Wired-OR bus signaling.

The SN65HVD2x devices are characterized for operation temperatures from –40°C to 85°C.

特性 Features

• Common-Mode Voltage Range (–20 V to 25 V) More Than Doubles TIA/EIA-485 Requirement
• Reduced Unit-Load for up to 256 Nodes
• Failsafe Receiver for Open-Circuit, Short-Circuit, and Idle-Bus Conditions
• More Than 100 mV Receiver Hysteresis
• Long Cable Solutions
• Security Networks
• Severe Electrical Environments
• Industrial Drives
• Avionics


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