STMicroelectronics digital isolators feature new thick oxide galvanic isolation technology for improved performance and reliability

     STMicroelectronics has started mass production of the STISO621 dual-channel digital isolator, a new series of high-performance isolators suitable for industrial control applications that can replace common optocouplers.

     The data transfer rate between the two isolation regions of STISO621 reaches 100Mbit/s, the pulse distortion is less than 3ns, and the galvanic isolation technology of 6kV thick oxide layer of STMicroelectronics is adopted. The device has two independent unidirectional channels, which can be adapted for a UART transceiver interface that handles bidirectional data. Each channel has a Schmitt trigger input to ensure that the isolator has high noise immunity.

     The supply voltages are independent of each other across the STISO621, which are galvanically isolated from each other. Each supply can switch levels between a wide voltage range of 3.3V and 5.5V. Typical Common Mode Transient Immunity (CMTI) of 65kV/µs protects the low side from high switching transients in harsh environments.

     STISO621 is suitable for a variety of industrial and consumer applications such as power supplies, motor drives, meters, inverters, battery monitors, appliances, fieldbus isolators, size-critical multi-channel isolation adapters, and general isolation throughout industrial automation systems class application. The product design meets the high voltage isolation equipment test specification VDE0884-10 and UL 1577.

     The evaluation board EVALSTISO62XV1 helps to speed up design in a variety of application scenarios. STMicroelectronics also offers the EVALSTPM-3PHISO, a reference design made specifically for the three-phase isolated electricity metering system use case. This design integrates the STISO621 for separating the high-voltage domain with ST's high-precision STPMS2 metering front-end IC, and also provides dedicated firmware running on an STM32 microcontroller to calculate the measured three-phase data and power quality data.

     With a maximum working isolation voltage (VIOWM) of 1200Vpeak and a high impulse withstand voltage (VIOTM), the STISO621 galvanic isolation function does not change over time, maintaining the integrity of the galvanic isolation function during any system fault. There are two package options, STISO621 in SO8 narrow body package with 4mm creepage distance and clearance, VIOTM voltage is 4800V. The STISO621W is available in an SO8 wide body package with 8mm creepage and clearance, and a VIOTM of 6000V. High performance is guaranteed in the temperature range from -40°C to 125°C.