Texas Instruments LM3404HVMAX/NOPB

Overview

LM3404HVMAX/NOPB from Texas Instruments is a monolithic 1-A constant-current buck regulator with integrated high-side N-channel MOSFET, designed specifically for driving high-power LED arrays in automotive and industrial lighting. It operates from 6 V to 75 V input, delivers up to 1.2 A output current, features 200-mV current-sense threshold, and supports PWM dimming via dedicated DIM pin.

For engineers reviewing the LM3404HVMAX/NOPB datasheet, LM3404HVMAX/NOPB pinout, LM3404HVMAX/NOPB application, or LM3404HVMAX/NOPB equivalent, key selection considerations include input voltage range (6–75 V), hysteretic controlled-on-time architecture, thermal shutdown at 165°C, SO PowerPAD-8 package thermal performance (R_θJB = 24.5°C/W), and compatibility with ceramic-only or capacitor-less output configurations.

Technical Context

The LM3404HVMAX/NOPB implements a controlled-on-time (COT) architecture combining hysteretic mode control with an external resistor–programmed on-timer that inversely scales with VIN. This eliminates need for loop compensation while maintaining stable switching frequency in continuous conduction mode (CCM).

It integrates a 7-V internal linear regulator (VCC), bootstrap gate driver (BOOT–SW), cycle-by-cycle current limiting (1.5-A typical), and dual protection comparators: CS overvoltage (300 mV) for open-LED detection and thermal shutdown (165°C/25°C hysteresis). The device requires no output capacitor for basic operation and supports all-ceramic output filtering.

Key Specifications

Pinout & Package

LM3404HVMAX/NOPB uses the SO PowerPAD-8 package (3.90 mm × 4.89 mm), featuring an exposed thermal pad (DAP) that must be soldered to PCB ground plane using 4–6 vias for optimal thermal performance (R_θJB = 24.5°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant-current LED driver applications.

Compared with LM3404MAX/NOPB, LM3404HVMAX/NOPB adds 33-V headroom for 48-V and 72-V DC systems; compared with MPQ4425HGJ-P, it trades synchronous rectification for simpler layout, built-in protection, and zero-compensation operation-favoring rapid deployment in ruggedized lighting designs.

Availability

LM3404HVMAX/NOPB is available at Aetrix Electronics and suitable for automotive headlamps, industrial high-bay fixtures, and outdoor streetlights requiring stable component supply across extended temperature and voltage ranges.

Supply support for LM3404HVMAX/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in power management ICs for industrial, automotive, and lighting markets.

The LM3404HV product line was developed to deliver robust, low-component-count constant-current LED drivers for harsh-environment applications where input voltage variation, thermal stress, and reliability are critical design constraints.

FAQ

What is the maximum input voltage supported by LM3404HVMAX/NOPB?

The LM3404HVMAX/NOPB supports a maximum input voltage of 75 V, as specified in its absolute maximum ratings. This rating enables use in 48-V and 72-V DC systems common in industrial and commercial lighting infrastructure. Operation above 75 V risks permanent damage; the device includes internal protection but is not rated for sustained overvoltage. Always maintain margin between nominal system voltage and this 75-V limit in LM3404HVMAX/NOPB designs.

How does the LM3404HVMAX/NOPB achieve constant LED current without output capacitors?

The LM3404HVMAX/NOPB achieves constant LED current without output capacitors by using a controlled-on-time (COT) buck topology that regulates based on inductor current valley detection. Its 200-mV CS threshold senses current through RSNS, and the hysteretic control loop directly manages MOSFET on-time to maintain average current. Because the inductor is directly in series with the LED, ripple current flows entirely through the LED-eliminating need for bulk output capacitance. This is validated in TI's Typical Application Diagram for LM3404HVMAX/NOPB.

What is the function of the RON pin on LM3404HVMAX/NOPB, and how is it used?

The RON pin on LM3404HVMAX/NOPB programs the controlled on-time (t_ON) of the internal MOSFET via an external resistor connected to VIN. t_ON scales inversely with input voltage and determines switching frequency and maximum output voltage capability. For example, a 200-kΩ resistor yields ~2.75 µs t_ON at 10 V and ~415 ns at 70 V. Grounding RON places LM3404HVMAX/NOPB into low-power shutdown (<100 µA), making it a dual-function pin for both frequency setting and system-level enable control.

Does LM3404HVMAX/NOPB provide protection against open-circuit LED failure?

Yes, LM3404HVMAX/NOPB provides open-circuit LED protection via its CS pin overvoltage comparator, which trips at 300 mV. When an LED string opens, CS voltage collapses, causing the controller to command maximum duty cycle-raising output voltage until the 300-mV threshold is exceeded, at which point the MOSFET is disabled. This prevents uncontrolled VO(MAX) rise and potential damage. TI recommends adding a Zener clamp (Z1 + RZ) for enhanced reliability, as documented in the LM3404HVMAX/NOPB datasheet Figure 18.

What thermal performance can be expected from LM3404HVMAX/NOPB in SO PowerPAD-8 package?

In the SO PowerPAD-8 package, LM3404HVMAX/NOPB achieves R_θJB = 24.5°C/W (junction-to-board) and R_θJA = 44.7°C/W (junction-to-ambient) when mounted on a 2-layer PCB with 4–6 thermal vias to an internal ground plane. This enables 1.2-A continuous operation at +85°C ambient with modest copper area. The exposed DAP must be soldered to ground; omitting vias or using insufficient copper raises junction temperature significantly. Thermal data is confirmed in LM3404HVMAX/NOPB Section 6.4 of the official datasheet.