Simplify design with high flexibility
Realizing savings in board space and material costs
STMicroelectronics today introduced the STR485LV, a 3.3V transceiver for RS485 applications. The transceiver provides external pins to select 20Mbps or 250kbps communication and supports direct interfacing with low-voltage logic down to 1.8V, enhancing design flexibility.

The ability to select the data rate allows designers to specify the same device, simplifying inventory management for RS485 networking applications. The range is from high-speed and short-distance to maximum communication distance (4000 feet), depending on cable performance. It is ideal for a variety of environments, including mobile communications infrastructure, high-speed data links, and low-voltage microcontroller communications.

Designers have the flexibility to connect low-voltage logic devices from 1.8 V to 3.3 V without using level-shifting components by leveraging the supply voltage range for data and enable signals. The STR485 allows up to 256 transceivers on the same RS485 compliant bus while maintaining internal driver output resistance greater than 96Ω up to 105°C.

The STR485 has safety and robustness features, including a thermal shutdown function to prevent bus contention or faults that result in excessive power consumption, and a receiver failsafe mode to prevent errors if inputs are idle, shorted, or unconnected.

The bus pins can withstand contact discharges exceeding ±8 kV and air discharges exceeding ±16 kV without latch-up exceeding the IEC 61000-4-2 specifications, and are resistant to IEC61000-4-4 fast transient burst Class B.

The STR485 is packaged in a 3mm x 3mm DFN10 form factor with flow-through logic-to-bus pinning that simplifies board design, and is priced starting at $1.55 in quantities of 1,000.