DESCRIPTION:

The LS7538 and LS7539 are CMOS integrated circuits which provide trigger pulses for triac phase control of incandescent lamps.

The circuits are designed to operate with a wide variety of lamp sizes ranging from small table lamps to large floor lamps.

The AGC Loop automatically adjusts Touch Sensitivity to be independent of lamp size.

FEATURES:

• Touch Sensitivity guaranteed to 600pF Touch Plate Capacitance.

• Touch Operation independent of line plug polarity.

• Pin selection of three available Brightness Step Sequences.

• Minimal external components.

• AGC Loop stabilizes immediately after Power-Up.

• Brightness state is Off after AC power applied.

• Brightness state is unchanged if AC power interrupted for < 0.5 sec.

• Advanced CMOS design for reliable operating characteristics and low power.

• 50/60 Hz Line Frequency.

• +6V to +9.5V Operation (VDD-VSS).

• LS7538, LS7539 (DIP); LS7538-S, LS7539-S (SOIC) - See Figure 1

APPLICATIONS:

• Screw-in and built-in adapter modules for converting table and floor lamps to touch control for step dimming.

• On-Off touch control of under-cabinet fluorescent lamps (LS7539 only).