Isolated RS485/RS422 transceiver with on-board power
The Analog Devices LTM2885IY#PBF is a µModule isolated RS422/RS485 transceiver that integrates the signal isolation, transceiver, and isolated DC-DC power supply into a single 42-BBGA package measuring 22x9 mm. It delivers 20Mbps data rate over a single unidirectional channel pair (1 driver, 1 receiver per side), with magnetic coupling technology providing 6500Vrms of galvanic isolation between the bus side and the logic side. The integrated isolated power means no external transformer or separate isolated supply is needed — just a single 5V rail on the logic side powers both sides of the barrier.
6500Vrms isolation — where it earns its keep
The 6500Vrms isolation rating is the highest among the µModule isolated RS485 parts and significantly higher than the 2500Vrms or 5000Vrms found on comparable devices from other families. This matters for motor drives, industrial inverters, and medical equipment where reinforced insulation or high transient overvoltages are required. The common-mode transient immunity of 50kV/µs means the receiver won't glitch when a nearby IGBT switches at several kV/µs — a real concern in variable-frequency drive environments.
20Mbps data rate with 4ns edge rates
The 20Mbps data rate with 4ns typical rise/fall times means this part can handle Profibus, Modbus RTU at high baud rates, or custom high-speed RS485 links. The fast edges demand attention to PCB layout — stub lengths on the bus should be minimised and termination resistors placed at the physical ends of the cable. The unidirectional channel architecture (one driver, one receiver per side) is designed for point-to-point or multi-drop RS485 networks where the bus master talks and listens on separate pairs.