The LTC2870/LTC2871CFE are robust pin-configurable multiprotocol transceivers, supporting RS232, RS485, and RS422 protocols, operating on a single 3V to 5.5V supply. The LTC2870 can be configured as two RS232 single-ended transceivers or one RS485 differential transceiver on shared I/O lines. The LTC2871CFE offers independent control of two RS232 transceivers and one RS485 transceiver, each on dedicated 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 tiny 2mm × 1.6mm inductor and one capacitor, eliminating the need for multiple supplies for driving RS232 levels.
Feature
- One RS485 and Two RS232 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
- High ESD: ±26kV (LTC2870), ±16kV (LTC2871)
- Logic Loopback Mode
- 1.7V to 5.5V Logic Interface
- Supports Up to 256 RS485 Nodes
- RS485 Receiver Failsafe Eliminates UART Lockup
- Available in 28-Pin 4mm × 5mm QFN and TSSOP (LTC2870), and 38-Pin 5mm × 7mm QFN and TSSOP (LTC2871)
Applications
- Flexible RS232/RS485/RS422 Interface
- Software Selectable Multiprotocol Interface Ports
- Point-of-Sale Terminals
- Cable Repeaters
- Protocol Translators
(Picture: Pinout)
