MAX3089

The MAX3080MAX3089 high-speed transceivers for RS-485/RS-422 communication contain one driver and one receiver. These devices feature fail-sacircuitry,which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This means that the receiver output will be a logictransmitterson a terminated bus are disabled (high impedance).The MAX3080/MAX3081/MAX3082 feature reducedslew-rate drivers that minimize EMI and reduce reflec-tions caused by improperly terminated cables, allowingerror-free data transmission up to 115kbps. The MAX3083/MAX3084/MAX3085 offer higher driver out-slew-rate limits, allowing transmit speeds up to 500kbps. The MAX3086/MAX3087/MAX3088's driver slew rates are not limited, making transmit speeds up10Mbps possible. The MAX3089's slew rate is selectable between 115kbps, 500kbps, and 10Mbps by driving a selector pin with a single three-state  driver.

These transceivers typically draw 375µA of supply current when unloaded, or when fully loaded with the drivers disabled.All devices have a 1/8-unit-load receiver input imped- ance that allows up to 256 transceivers on the bus. TheMAX3082/MAX3085/MAX3088 are intended for half-duplex communications, while the MAX3080/MAX3081/ MAX3083/MAX3084/MAX3086/MAX3087 are intended for full-duplex communications. The MAX3089 is selec- table between half-duplex and full-duplex operation. It also features independently programmable receiver and transmitter output phase viaseparate pins.