Superior Flexibility of RS-485-Networking Transceiver from STMicroelectronics Simplifies Design, Saves Board Space and Bill of Materials

STMicroelectronics STR485

The STMicroelectronics STR485LV 3.3 V transceiver for RS-485 applications enhances design flexibility by providing an external pin to select 20 Mbps or 250 kbps communication and interfacing directly with low-voltage logic down to 1.8 V.

STMicroelectronics - STR485

The user-selectable data rate allows designers to specify the same device and thus simplify inventory management for RS-485-networking applications, ranging from high-speed/short-range up to the maximum communication distance (4000 feet) depending on cable performance. It is ideal for a wide variety of scenarios, including telecom infrastructure, high-speed data links, or low-voltage microcontroller communications.

Designers get the flexibility to connect low-voltage logic devices from 1.8 V to 3.3 V directly, without needing level-shifting components, leveraging the 1.65-3.6V supply-voltage range for data and enable signals.

By maintaining internal driver-output resistance above 96 Ω up to 105 °C, the STR485 allows up to 256 transceivers on the same bus in accordance with the RS-485 specification.

Rich features for safety and robustness include thermal shutdown to prevent bus contention or faults causing excessive power consumption, and a receiver failsafe mode that prevents errors if inputs are idle, shorted, or unconnected. The bus pins withstand over ±8 kV contact discharge and ±16 kV air discharge without latch-up, exceeding IEC 61000-4-2 specifications, and are resistant to IEC 61000-4-4 fast transient burst class-B.

Packaged as a 3 mm × 3 mm DFN10 featuring flow-through logic-to-bus pinning that simplifies board design, the STR485 is available now from $1.55 for orders of 1000 pieces.

Example of implementation in a PCB
Example of implementation in a PCB.
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