LS7534, LS7535, LS7535FT are MOS integrated circuits designed for brightness control of incandescent lamps. They are controlled by touch plates (LS7534) or pushbutton switches (LS7535) and the output can be adjusted between 159 degrees (maximum brightness) and 41 degrees (minimum brightness) depending on the firing angle of the triac. All internal timings are synchronized with the line frequency by means of a built-in phase-lock loop circuit.
The LS7534, LS7535 and LS7535FT are MOS integrated circuits designed for brightness control of incandescent lamps in dimmer light switch applications. They use a phase‑lock loop to synchronize with the AC line frequency and generate a controllable firing angle for a triac.
The document details features such as soft turn‑on/off, duty‑cycle control from 23% to 88%, and dual up/down inputs. It includes pin assignments, absolute maximum ratings, electrical characteristics, timing diagrams, and example schematics for touch‑plate (LS7534) and push‑button (LS7535) dimmer circuits.
| Supply voltage (Vss‑VDD) | +12 V to +18 V |
|---|---|
| Maximum DC supply voltage | +20 V |
| Operating temperature | 0 °C to +80 °C |
| Supply current (Iss) | 1.2 mA to 1.7 mA (typical at Vss = +15 V) |
| TRIG pulse width | 33 µs |
| Conduction angle range | 41° to 159° |
The ramp‑up time from off to full‑on is 2.8 seconds.
It controls the duty cycle from 23 % to 88 %.
The devices operate with a supply voltage between +12 V and +18 V (up to +20 V absolute maximum).