UM491 数据手册 ( 数据表 ) - Union Semiconductor, Inc.

General Description
   The UM488/UM491 is ±15kV electrostatic discharge (ESD)-protected, high-speed transceivers for RS-422 communication that contain one driver and one receiver. The UM491 contains an additional receiver and driver enable control. The device features fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This means that the receiver output will be a logic high if all transmitters on a terminated bus are disabled (high impedance). The UM488/UM491 offers higher driver output slew-rate limits, allowing transmit speeds up to 2.5Mbps. The device features enhanced ESD protection. All transmitter outputs and receiver inputs are protected to ±15kV using the Human Body Model.

FEATUREs
● ESD Protection for RS-422 I/O Pins ±15kV, Human Body Model
● True Fail-Safe Receiver while Maintaining EIA/TIA-422 Compatibility
● Enhanced Slew-Rate Limiting Facilitates Error-Free Data Transmission
● 1nA Low-Current Shutdown Mode (UM491)
● Allow up to 256 Transceivers on the Bus

APPLICATIONs
● RS-422 Communications
● Level Translators
● Transceivers for EMI-Sensitive Applications
● Industrial-Control Local Area Networks