ST AC motor switches deliver built-in protection, enhanced switching

st-acmotorswitchesGeneva, Switzerland — STMicroelectronics has unveiled its latest generation of AC switches, aimed at appliance motor control. Since these devices come with built-in protection and enhanced switching, they eliminate many of the additional components typically needed to ensure smooth switching and protection, lowering costs for heavy-duty home appliances such as washing machines and refrigerators.

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 2 kV on the AC line, in accordance with the international IEC 61000-4-5.

The ACST410 and ACST610 switches have a low trigger current of 10 mA, 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 V and 2000 V per microsecond, respectively, complying with the IEC 61000-4-4 fast transient burst test and eliminating any need for conditioning of the trigger signal. Competing switches typically have lower, or unspecified, noise immunity, said ST.

The devices feature 4A (ACST4), 6A (ACST6) or 8A (ACST8) maximum on-state current, together with an 800-V blocking voltage and 100-A per microsecond turn-on rate.

The devices are available in a TO-220FAB package (1500 Vrms insulation) with surface-mount DPAK and D2PACK packages options available.

Pricing: From $0.70 in quantities of 10,000.