Analog Devices has introduced RS-485 and RS-422 transceivers that can withstand 5.7kVrms and ±15kV ESD.

“The transceivers’ simplified PCB layout and small form factor pack more functionality into space constrained applications than the previous generation,” said ADI.

There will be four products:

• ADM2867E 25Mbit/s full duplex, separate driver and receiver cable inversions pins
• ADM2865E 25Mbit/shalf duplex, combined cable inversion pin
• ADM2863E 500kbit/s full duplex, separate driver and receiver cable inversions pins
• ADM2861E 500kbit/s half duplex, combined cable inversion pin

Of these: ADM2867E is available now in a ~10 x 10mm 28 pin fine-pitch SOIC, (same footprint as a 16 lead SOIC), and the ADM2561E with 3kV isolation in the same package has also released.

The cable invert pins allowing the user to correct reversed cable connection on the A, B, Y, and Z bus pins while maintaining receiver fail-safe. “This adjustment can be implemented in software on the controller driving the RS485 transceiver,” according to the company. “ADM2863E and ADM2867E feature separate digital logic pins to correct cases where the driver, receiver, or both are wired in reverse.”

Devices, according to ADI, will pass radiated emissions testing to the EN55032 Class B standard with margin on a two-layer PCB using two external 0402 ferrites on isolated power and ground pins: “margin to CISPR32 Class B emissions on a two-layer PCB without stitching capacitance”, added ADI.

On-board is an isolated dc-to-dc converter – so no need for an external isolated power supply.

For compatibility with various inputs and outputs, including FPGAs and PROFIBUS, supply voltages can be set in a number of ways:

• 3V to 5.5V in (Vcc) for dc-dc converter
• 1.7V to 5.5V in for logic-side IO
• Selectable 5V or 3.3V out from dc-dc for to bus-side supply (5V only if Vcc >4.5V)

±12kV contact and ±15kV air IEC61000-4-2 ESD protection is provided on the RS-485 A, B, Y, and Z pins.

The two slew-rate limited versions (ADM2861E and 2863E), whose release dates have not been announced, are optimised for long cable runs.

Operation is over -40°C to +105°C