RS-485/RS-422 transceiver for industrial bus lines
The Maxim Integrated MAX3440EESA+T is a half-duplex transceiver supporting both RS-485 and RS-422 protocols, with one driver and one receiver integrated in an 8-pin SOIC package. It operates from a single 5V supply (4.75V to 5.25V) and is rated for industrial temperature environments from -40°C to 85°C. The device is commonly used in factory automation, building control, and other differential-bus applications where robust communication over twisted-pair cabling is required.
250kbps data rate — what it means for bus timing
Rated for a maximum data rate of 250kbps, this transceiver is suited for applications like PLC-to-sensor links, HVAC zone controllers, and serial data acquisition where throughput is modest but cable runs can extend beyond 100 meters. The slew-limited edge rate helps control EMI emissions on long stubs, a practical advantage when routing the bus through a factory floor or outdoor conduit.
Receiver hysteresis and noise margin
The receiver includes 25 mV of hysteresis, which improves noise immunity on differential lines subject to ground shifts or coupled interference. For a 5V bus with standard termination, this margin reduces the likelihood of bit errors on runs where common-mode noise is present but within the transceiver's input range.
Lifecycle and sourcing
This part is ROHS3 compliant.