STMicroelectronics STR485LV 3.3V RS485 Transceiver Simplifies Design & Saves Board Space

The STMicroelectronics STR485LV 3.3V transceiver for RS485[1] applications enhances design flexibility by providing an external pin to select 20Mbps or 250kbps communication and interfacing directly with low-voltage logic down to 1.8V.

The user-selectable data rate allows designers to specify the same device and thus simplify inventory management for RS485-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 1.8V to 3.3V 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 96Ω up to 105°C, the STR485 allows up to 256 transceivers on the same bus in accordance with the RS485 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 ±8kV contact discharge and ±16kV air discharge without latch-up, exceeding IEC 61000-4-2 specifications, and are resistant to IEC61000-4-4 fast transient burst class-B.

Packaged as a 3mm x 3mm 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.