The Texas Instruments LM3445MM/NOPB is an AC DC Offline Switcher controller designed for LED lighting applications that require Triac dimming compatibility. It uses a Step-Down (Buck) topology, operates from an 8V to 12V supply, and switches at a frequency adjustable from 30kHz to 1MHz. The controller has no internal power switch — it drives an external MOSFET — and delivers a single regulated output. The 10-VSSOP package suits compact LED driver boards in retrofit bulbs, downlights, and other mains-powered luminaires where dimmer compatibility is needed.
The wide range also accommodates automotive exterior lighting if the supply rail is derived from the vehicle's 12V bus — though the part itself is not AEC-Q100 listed in the record.
Switching frequency — inductor sizing vs efficiency
The 30kHz to 1MHz range lets you trade inductor size against switching losses.
No internal switch — external MOSFET required
Because the LM3445MM/NOPB has no internal switch, the BOM includes an external MOSFET and its gate-drive components. This adds board area but gives flexibility to choose the FET based on the output current and voltage stress of the specific LED load. For a 1A output at 12V, a small SOT-23 MOSFET suffices; higher currents need a larger DPAK or similar.