A multiprotocol transceiver with switchable integrated termination for 3.3V and 5V systems has been developed by Linear Technology Corporation.
RS485 systems require a termination resistor on the ends of the communication bus to minimise signal reflections. The LTC2872 integrates pin-controlled termination resistors for easy interface reconfiguration, eliminating external resistors and control relays.
The termination resistors, when enabled, are automatically switched in or out to match the transceiver’s protocol selection of RS232 or RS485.
The device also features high ESD protection: ±16kV HBM on the transceiver bus pins, when powered off or operating.
The device can be configured as four RS232 single-ended transceivers or two RS485 differential transceivers, or a combination of both, on shared I/O lines, reducing component count for multiprotocol networks. This offers configurability out in the field.
The transceiver is suitable for a wide range of applications, including software-selectable multiprotocol interface ports, point-of-sale terminals, security cameras, cable repeaters and protocol translators.
An optional 1.7V to 5.5V logic supply enables convenient digital interfacing and an integrated DC/DC boost converter eliminates the need for multiple supplies to drive RS232 levels.