What is the MAX253EPA+ and what does it do?
The MAX253EPA+ from Analog Devices (formerly Maxim Integrated) is a transformer driver specifically designed for isolated RS485 interfaces. It takes a 3.3V or 5V supply and drives a center-tapped transformer to create the isolated power rail for the RS485 transceiver side.
Supply current is 450 µA typical — that's the current the driver itself consumes, not the load it can deliver to the transformer. The 3.3V and 5V supply rating means you can use either rail without a jumper or LDO; the part self-adjusts.
The 8-DIP package is a rework tech's best friend. Through-hole leads are robust enough to survive multiple soldering cycles; a hot-air station set to 300°C will lift the part cleanly without pad damage if you need to swap it. The 0.300" body width fits standard DIP sockets, so you can socket it during prototyping and solder it in production.