Improved Tandem Diodes from STMicro Offered as Economical Alternative to SiC

STMicroelectronics NV has unveiled its second-generation of tandem diodes, which enable designers to cost-effectively enhance the energy efficiency of equipment such as power supplies, solar inverters, and e-transportation charging points. Compared to first-generation devices, the new diodes have even lower reverse-recovery charge (QRR) to minimize switching losses, further extending their efficiency advantage over standard ultrafast diodes. The lower QRR also speeds up the fine-tuning of circuit designs, enabling faster time to market.

With more than 50 million units shipped, ST’s tandem diodes are now entering the second generation. Formed with two dice in the package, as for the previous generation, these ultrafast Tandem diodes are claimed to be the fastest 600 V silicon diodes on the market. For switching frequencies up to 100kHz, and junction temperature below 100 °C, the performance of these diodes is very close to that of silicon-carbide (SIC) diodes, which are typically at least 30% more expensive. The key advantage of this solution resides in its price versus performance, compared to other solutions available on the market.

The second-generation devices joining ST’s 600V tandem diode range are the STTH8T06DI and STTH8ST06DI rated for 8A average forward current, and the STTH12T06DI is for applications up to 12A. The devices have peak forward surge-current ratings equivalent to those of ultrafast diodes, ensuring robustness and reliability, and a wide operating junction-temperature range of -40°C to 175°C. All devices are in mass production now in the TO-220AC isolated-tab package, priced from $1.57 for the STTH8T06DI in quantities of over 1,000 pieces.