FEATURES

Controlled Baseline

− One Assembly/Test Site, One Fabrication

Site

Extended Temperature Performance of −55°C

to 125°C

Enhanced Diminishing Manufacturing

Sources (DMS) Support

Enhanced Product-Change Notification

Qualification Pedigree†

Common-Mode Voltage Range (−20 V to 25 V)

More Than Doubles TIA/EIA-485 Requirement

Receiver Equalization Extends Cable Length,

Signaling Rate (HVD23, HVD24)

Reduced Unit-Load for up to 256 Nodes

Bus I/O Protection to Over 16-kV HBM

Failsafe Receiver for Open-Circuit,

Short-Circuit and Idle-Bus Conditions

Low Standby Supply Current 1.5-μA Max

More Than 100 mV Receiver Hysteresis

APPLICATIONS

Long Cable Solutions

− Factory Automation

− Security Networks

− Building HVAC

Severe Electrical Environments

− Electrical Power Inverters

− Industrial Drives

− Avionics

DESCRIPTION

The SN65HVD21M offers performance exceeding typical RS−485 devices. In addition to meeting all

requirements of the TIA/EIA−485−A standard, the HVD2x family operates over an extended range of

common-mode voltage, 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.

The SN65HVD21M is 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.

The SN65HVD21M combines a 3-state differential driver and a differential receiver, which operates 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 SN65HVD21M 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.