RS232/RS485 Dual Multiprotocol Transceiver with Integrated Termination

The LTC2872 is a robust pin-configurable transceiver that supports RS232, RS485, and RS422 standards while operating on a single 3V to 5.5V supply. The LTC2872 can be configured as four RS232 single-ended transceivers or two RS485 differential transceivers, or combinations of both, on shared I/O lines.

Pin-controlled integrated termination resistors allow for easy interface reconfiguration, eliminating external resistors and control relays. Half-duplex switches allow four-wire and two-wire RS485 configurations. Loopback mode steers the driver inputs to the receiver outputs for diagnostic self-test. The RS485 receivers support up to 256 nodes per bus, and feature full failsafe operation for floating, shorted or terminated inputs.

An integrated DC/DC boost converter uses a small inductor and one capacitor, eliminating the need for multiple supplies for driving RS232 levels.

Applications

* Flexible RS232/RS485/RS422 Interface

* Software Selectable Multiprotocol Interface Ports

* Point-of-Sale Terminals

* Cable Repeaters

* Protocol Translators

* PROFIBUS-DP Networks

* Four RS232 and Two RS485 Transceivers* 3V to 5.5V Supply Voltage* 20Mbps RS485 and 500kbps RS232* Automatic Selection of Integrated RS485 (120Ω) and RS232 (5kΩ) Termination Resistors* Half-/Full-Duplex RS485 Switching* Logic Loopback Mode