This document introduces the features and characteristics of the LM3406/06HV product. The LM3406/06HV is a monolithic switching regulator designed to deliver constant currents to high power LEDs. It is ideal for automotive, industrial, and general lighting applications. The product also supports pulse width modulation (PWM) dimming, which can be achieved using a dedicated logic pin or by PWM of the power input voltage.
The LM3406 and LM3406HV are monolithic switching regulators designed to deliver constant currents to high‑power LEDs for automotive, industrial, and general lighting applications. They include an integrated 2.0 A N‑channel MOSFET, a wide input voltage range, PWM dimming via a dedicated logic pin or power‑input modulation, and protection features such as low‑power shutdown and thermal shutdown.
The device uses a controlled‑on‑time architecture with a comparator and one‑shot timer to maintain a constant switching frequency across varying input and output voltages. LED current is set by an external sense resistor, and the regulator provides internal bias regulation, a high‑voltage bias regulator, and detailed pin functions for configuration and monitoring.
| Input voltage range (LM3406) | 6 V to 42 V |
|---|---|
| Input voltage range (LM3406HV) | 6 V to 75 V |
| Integrated MOSFET current limit | 2.0 A (typical) |
| Thermal shutdown threshold | 165 °C |
| Minimum on‑time | 280 ns (typical) |
The LM3406 operates from 6 V to 42 V, while the LM3406HV operates from 6 V to 75 V.
LED current is set by a sense resistor calculated as R_sense = 0.2 / I_LED.
The minimum on‑time is 280 ns (typical).