Renesas Electronics America Inc. ISL81387 series Drivers Interface ICs

The ISL81387 series is a BiCMOS interface IC that can be configured by the user as either a single RS-422, RS-485 differential transceiver, or as a dual (2 Tx, 2 Rx) RS-232 transceiver. It is designed to provide ±15kV ESD protection and is capable of operating at 5V. In RS-232 mode, the on-board charge pump generates RS-232 compliant ±5V Tx output levels, from a supply as low as 4.5V. Four small 0.1µF capacitors are required for the charge pump. The transceivers are RS-232 compliant, with the Rx inputs handling up to ±25V, and the Tx outputs handling ±12V. In RS-485 mode, the transceivers support both the RS-485 and RS-422 differential communication standards. The RS-485 receiver features full fail-safe operation, so the Rx output remains in a high state if the inputs are open or shorted together. The RS-485 transmitter supports up to three data rates, two of which are slew rate limited for problem-free communications. The charge pump disables in RS-485 mode, thereby saving power, minimizing noise and eliminating the charge pump capacitors. Both RS-232, RS-485 modes feature loopback and shutdown functions.