SP337EBEY-L [EXAR]

The SP337E is a dual mode serial transceiver containing both RS-232 and RS-485/422 line drivers and receivers. The RS-232 mode provides three drivers and five receivers to support all eight signals commonly used in the DB9 serial port connector (3TX/5RX). In RS-485 mode the device features two independent high speed RS-485/422 transmit and receive channels (2TX/2RX). The default RS-485 configuration is full-duplex, but half-duplex operation can be obtained by tying together the TX and RI pins, and the TXEN and RXEN signals. The SP337E is pin compatible to Exar's SP334. The SP337EB features a maximum data rate of 250kbps in RS-232 mode and a maximum data rate of 15Mbps in RS-485. However, the SP337EU features a maximum data rate of 1Mbps in RS-232 mode and a maximum data rate of 15Mbps in RS-485 mode. The Exar-patented high efficiency charge pumps (5,306,954) deliver true RS-232 driver output voltages from a single power supply from 3.3V to 5V. Charge pump outputs are self-monitored to minimize power consumption. The SP337E requires only four 0.1μF capacitors for complete functionality. All RS-485 receivers or transceivers feature high impedance inputs which allow up to 256 transceivers on a single shared bus. When configured in RS-485 mode, each driver may be individually enabled or put into tri-state, simplifying use on shared buses or for bidirectional communication. The RS-485/422 drivers can be disabled (high-Z output) by the TXEN enable pin. The RS-232 receiver outputs can be disabled by the RXEN enable pin. All receivers have advanced failsafe protection to prevent oscillation when inputs are un-connected. In RS-232 mode, each receiver input has a 5kΩ pull-down to ground. in RS-485 mode, receivers will default to output logic 1 if inputs are floating, shorted, or open but terminated. All driver outputs and receiver inputs are protected against ESD strikes up to +/-15,000 volts.