Pulse distortion less than 3ns, at 100Mbit/s speed
Data transfer between two isolated domains is possible.
VIOWM, VIOTM, Maintaining Galvanic Insulation Integrity


STMicroelectronics announced on the 27th the launch and commencement of mass production of the 'STISO621' dual-channel digital isolator, which replaces general-purpose optocouplers in industrial applications.

The STISO621 utilizes ST's 6kV oxide-based galvanic isolation technology to transmit data between two isolated domains at speeds of up to 100Mbit/s with pulse distortion of less than 3ns. It functions as a UART interface, processing data bidirectionally using two independent unidirectional channels. Schmitt-trigger inputs for each channel also ensure high noise immunity.

The two sides of the STISO621 are galvanically isolated and have independent supply voltages. Each side has a voltage range of 3 to 5 V, enabling level conversion between 3.3 V and 5 V circuits. This protects the low-voltage side from high switching transients in harsh environments with a common-mode transient immunity (CMTI) of typically 65 kV/µs.

The STISO621 is suitable for a wide range of industrial and consumer applications, including power supplies, motor drives, meters, inverters, battery monitors, home appliances, fieldbus isolators, size-critical multichannel isolation adapters, and general isolation across industrial automation systems. ST has verified the design according to VDE0884-10 and UL 1577, specifications typically applicable to isolation devices for high-voltage applications.

Engineers can calculate metering and power quality data by combining the STPMS2 metering front-end IC, custom firmware based on an STM32 MCU, and the STISO621 isolator with the 'EVALSTISO62XV1' product evaluation board and the 'EVALSTPM-3PHISO' metering evaluation board. The 849Vrms maximum working isolation voltage (VIOWM), high impulse withstand voltage (VIOTM), and galvanic isolation integrity are maintained over time even in the event of system faults.

The STISO621 is available in two packages. The narrow-body SO8 package with 4mm creepage and clearance provides a VIOTM of 4,800V. The wide-body SO8 package with 8mm creepage and clearance provides a VIOTM of 6,000V. Both the STISO621 and STISO621W, which are currently in production, are priced at $0.97 for 1,000-unit quantities. The EVALSTISO62XV1 is priced at $25, and the EVALSTPM-3PHISO is priced at $118.