STMicroelectronics (ST) has unveiled new ac switches that are well suited for controlling appliance motors. According to ST, these ac switches can be used without many of the additional components normally needed to ensure smooth switching and provide protection. The new devices will allow one-stop design for heavy-duty home appliances such as washing machines or refrigerators. The company says consequent ruggedness will lower the end products’ total cost of ownership.
The latest-generation ACST4, ACST6 and ACST8 switches include a power triac delivering enhanced commutation performance to turn the motor off without requiring external components to suppress voltage transients and to ensure reliable switching. Unlike conventional triacs, the switches also integrate protection against surge voltages up to 2kV on the ac line, in accordance with the international IEC 61000-4-5.
In addition, the ACST410 and ACST610 switches have a low trigger current of 10mA, allowing direct control by a CMOS device such as a microcontroller without requiring a buffer or driver. The ACST435 and ACST830 are high-immunity devices specifying noise immunity of at least 1000 and 2000V per microsecond, respectively, complying with the IEC 61000-4-4 fast transient burst test and eliminating any need for conditioning of the trigger signal.
Key features of the ACST4/6/8 families include: 4A (ACST4), 6A (ACST6) or 8A (ACST8) maximum on-state current; 800V blocking voltage; 100A per microsecond turn-on rate; TO-220FPAB (full-pack) package, 1500Vrms insulation; and surface-mount DPAK and D2PAK packages are also available.
The ACST4, ACST6 and ACST8 families comprise 14 part numbers in total, and are priced from $0.70 in quantities of 10,000. Further pricing options are available for larger quantities.
