ACST4 Series

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The ACST4 device has been designed to switch on & off low power, but highly inductive or resistive loads

such as dishwashers spray pumps, and air-conditioners fan.

Pin COM: Common drive reference to connect to the power line neutral

Pin G: Switch Gate input to connect to the digital controller

Pin OUT: Switch Output to connect to the load

ACST4-7S triggering current has to be sunk from the gate pin G. The switch can then be driven directly by

logic level circuits through a resistor as shown on the typical application diagram ( Fig A ).

Thanks to its thermal and turn off commutation performances, the ACST4 switch is able to drive with no

turn off additional snubber an inductive load up to 4 A.

AC LINE SWITCH BASIC APPLICATION

OUT

COM

G

ACST4

ST72 MCU

N

AC

MAINS

L

R

- Vcc

M

LOAD

OUT

L

TYPICAL APPLICATION DIAGRAM (Fig. A)

The ACST4 switch is able to sustain safely the AC line transient voltages either by clamping the low energy

spikes or by breaking over under high energy shocks, even with high turn-on current rises.

The test circuit of the figure 2 is representative of the final ACST application and is also used to stress the

ACST switch according to the IEC 61000-4-5 standard conditions. Thanks to the load, the ACST switch

sustains the voltage spikes up to 2 kV above the peak line voltage. It will break over safely even on resistive

load where the turn on current rate of rise, is as high as shown on figure 3. Such non-repetitive test can be

done 10 times on each AC line voltage polarity.

AC LINE TRANSIENT VOLTAGE RUGGEDNESS