STMicro Announces Ultra-Miniature Transil™ Family Of Surge Suppresion Diodes
STMicroelectronics has introduced the SMM4F family of unidirectional Transil™ voltage surge-suppression diodes, which is said to improve performance in three key areas by delivering high protection within a small footprint, reducing leakage current for low losses, and raising maximum junction temperature for enhanced reliability.
The SMM4F family protects against 400W 10/1000µs surges and has a footprint of 3.8 x 1.9mm. Said to be smaller than existing 400W devices in SMA packages, the SMM4F diodes are also said to provide 100% more protection than 200W alternatives currently offered in the 10% smaller SMF outline. Low leakage current of 0.2µA ensures low-loss performance for use in battery-operated devices or other low-power applications. With a maximum leakage current of 1µA at 85°C, the SMM4F family is suitable for telecom applications.
The family includes a total of 14 devices with stand-off voltages between 5 and 33V providing a suitable part for the majority of applications requiring surge suppression diodes, including SMPS, consumer electronics, computing devices and telecom equipment. Each is rated to 175°C maximum junction temperature, which is said to allow a greater safety margin than conventional alternatives that are typically rated to only 150°C.
ST has also characterized additional parameters, providing designers with reliable data to predict behavior accurately under a variety of operating conditions. The maximum clamping voltage and peak-power current are specified for surges of 8/20µs in addition to 10/1000µs, allowing designers to verify protection meeting the widely accepted IEC61000-4-5 standard.
ST claims that designers also benefit from accurate data for dynamic resistance, variation of breakdown voltage with temperature, and leakage current versus junction temperature. The company states that it is the only manufacturer to provide this information, which allows designers to calculate the clamping voltage accurately, according to actual surge-current and junction-temperature values.
The SMM4F family is housed in the RoHS-compliant and halogen-free, JEDEC-registered STmite package. Production units are available at $0.10 for quantities of 10,000 pieces and above.
