What this part is and where it fits
The Texas Instruments LM3402HVMM/NOPB is a DC-DC buck regulator designed specifically for constant-current LED lighting applications. It integrates the switching FET internally and operates at a fixed 1MHz switching frequency, which allows the use of small inductors and ceramic capacitors, keeping the overall solution compact. The part supports PWM dimming, making it compatible with external microcontroller or PWM controller inputs for brightness control. Typical applications include architectural lighting, automotive exterior and interior lighting, industrial signage, and general-purpose constant-current LED drivers where a wide input voltage range and high output voltage are required.
Input voltage range and what it means for your design
The LM3402HVMM/NOPB accepts an input supply from 6V up to 75V. That 6V minimum means it can run from a standard 12V or 24V industrial supply, an automotive battery during cranking (down to 6V), or a 48V telecom rail without needing a separate pre-regulator. The 75V maximum headroom handles load-dump transients in automotive environments and unregulated rectified AC lines in industrial lighting. For the board layout engineer, this wide range means the input capacitor must be rated for at least 75V DC, and the inductor must handle the peak current at the lowest input voltage without saturating.
Output voltage and current: driving the LED string
The regulator delivers up to 500mA per channel with an output voltage as high as 73V. That 73V ceiling supports a series string of white LEDs in a common configuration for high-bay lighting or automotive headlamp modules.