UM3085EESA 半双工RS485收发器

Key Specifications

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Product Description

The UM3085EESA are ±15kV ESD-protected, high-speed transceiversfor RS-485 communication that contain one driver and one receiver.These devices feature fail-safe circuitry, which guarantees alogic-high receiver output when the receiver inputs are open,shorted or idle. This means that the receiver output will be logichigh if all transmitters on a terminated bus are disabled (highimpedance). The UM3085E features reduced slew-rate driver thatminimizes EMI and reduces reflections caused by improperlyterminated cables, allowing error-free data transmission up to500kbps. The devices feature enhanced ESD protection. Alltransmitter outputs and receiver inputs are protected to ±15kVusing the Human Body Model and IEC61000-4-2, Air-GapDischarge.

The transceivers typically draw 400μA of supply current whenunloaded, or when fully loaded with the drivers disabled. Alldevices have a 1/8-unit-load receiver input impedance that allowsup to 256 transceivers on the bus and are intended for half-duplexcommunications.

Features

- ESD Protection for RS-485 I/O Pins

  ±15kV—Human Body Model

  ±15kV—IEC61000-4-2, Air-Gap Discharge

- True Fail-Safe Receiver while Maintaining EIA/TIA-485Compatibility

- Enhanced Slew-Rate Limiting Facilitates Error-Free DataTransmission

- 2nA Low-Current Shutdown Mode

- -7V to +12V Common-Mode Input Voltage Range

- Allows up to 256 Transceivers on the Bus

- Thermal Shutdown

- Current-Limiting for Driver Overload Protection

Typical Operating Circuits

Applications

- RS-485 Transceivers

- Level Translators

- Industrial-Control Local Area Networks

- Transceivers for EMI-Sensitive Applications

Communication Function Table

Table1.Transmitting                       

X=Don’t care; High-Z=High Impedance

Table2. Receiving