HT490EARZ

HT481, HT483, HT485, HT487 through HT491, and HT1487 are low-power transceivers for RS-485 and RS-422 communications. Each device contains one driver and one receiver. HT483, HT487, HT488, and HT489 feature slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly terminated cables, enabling error-free data transmission at up to 250kbps. The drivers of HT481, HT485, HT490, HT491, and HT1487 are not slew-rate limited, allowing them to transmit data at up to 2.5Mbps. These transceivers draw supply current between 120μA and 500μA when the driver is unloaded or fully loaded but disabled. In addition, HT481, HT483, and HT487 feature a low-current shutdown mode that draws only 0.1μA. All devices operate from a single 5V supply. The drivers feature short-circuit current limiting and are protected against excessive power dissipation by a thermal shutdown circuit that places the driver outputs in a high-impedance state. The receiver inputs include a failsafe feature that guarantees a logic-high output when the inputs are open-circuited. HT487 and HT1487 feature one-quarter unit load receiver input impedance, allowing up to 128 HT487/HT1487 transceivers to be connected on the bus. HT488 through HT491 support full-duplex communication, while HT481, HT483, HT485, HT487, and HT1487 are designed for half-duplex applications.

Applications

• Low-power RS-485 transceiver
• Low-power RS-422 transceiver
• Level translator
• Transceiver for EMI-sensitive applications
• Industrial control LAN