LM3433 is an adaptive constant on-time DC/DC buck constant current controller that provides a constant current for illuminating high power LEDs. The output configuration allows the anodes of multiple LEDs to be tied directly to the ground referenced chassis for maximum heat sink efficacy. The high frequency capable architecture allows the use of small external passive components and no output capacitor while maintaining low LED ripple current. Two control inputs are used to modulate LED brightness. An analog current control input is provided so the LM3433 can be adjusted to compensate for LED manufacturing variations and/or color temperature correction. The other input is a logic level PWM control of LED current. The PWM functions by shorting out the LED with a parallel switch allowing high PWM dimming frequencies. High frequency PWM dimming allows digital color temperature control, interference blanking, field sequential illumination, and brightness control. Additional features include thermal shutdown, VCC under-voltage lockout, and logic level shutdown mode. The LM3433 is available in a low profile LLP-24 package.
The LM3433 is an adaptive constant‑on‑time DC/DC buck controller that delivers a regulated constant current for high‑power LEDs. It supports common‑anode configurations, allowing LED anodes to be tied directly to chassis ground for optimal heat‑sink performance. The device operates with high‑frequency PWM dimming, enabling digital color‑temperature control, interference blanking, and field‑sequential illumination.
Key features include an operating input voltage range of –9 V to –14 V, output current greater than 6 A, PWM frequency capability above 30 kHz, and operation without an external output capacitor. The LM3433 is supplied in a low‑profile LLP‑24 package and includes protection functions such as thermal shutdown and under‑voltage lockout.
| Maximum Output Current | >6 A |
|---|---|
| PWM Frequency Capability | >30 kHz |
| Operating Input Voltage Range | -9 V to -14 V (w.r.t. LED anode) |
| Output Capacitor Requirement | None required |
| Package | LLP‑24 |
The device can deliver an output current greater than 6 A.
It operates with an input voltage between –9 V and –14 V referenced to the LED anode.
No, the LM3433 does not require an output capacitor.
The LM3433 is capable of PWM frequencies greater than 30 kHz.