Texas Instruments LM3404HVMR/NOPB

Overview

LM3404HVMR/NOPB from Texas Instruments is a monolithic 1-A constant-current buck regulator IC designed for high-power LED driving in automotive and industrial lighting systems. It integrates a high-side N-channel MOSFET (R_DS(on) = 0.75 Ω typ), operates from 6 V to 75 V input, delivers up to 1.2-A output current, features hysteretic controlled on-time architecture, and supports PWM dimming via the DIM pin.

For engineers reviewing the LM3404HVMR/NOPB datasheet, LM3404HVMR/NOPB pinout, LM3404HVMR/NOPB application, or LM3404HVMR/NOPB equivalent, key selection considerations include its 75-V max input rating, 200-mV current-sense threshold, thermal shutdown at 165°C, SO PowerPAD-8 package with exposed thermal pad, and compatibility with ceramic-only or capacitor-less output configurations.

Technical Context

The LM3404HVMR/NOPB implements a Controlled On-Time (COT) architecture combining hysteretic mode control with an external resistor–programmable one-shot timer. Its CS pin compares sensed voltage against a precise 200-mV reference to regulate LED current, while RON sets t_ON inversely proportional to VIN - enabling stable operation across wide input ranges without loop compensation.

It integrates a 7-V internal linear regulator (VCC), bootstrap gate drive for the high-side MOSFET, cycle-by-cycle current limiting (1.5-A typ), and fast PWM dimming with TTL-compatible DIM input (V_IL = 0.8 V, V_IH = 2.2 V). Thermal shutdown (165°C/25°C hysteresis) and open-LED protection via OVP/OCP comparator (300-mV threshold) are built-in.

Key Specifications

Pinout & Package

LM3404HVMR/NOPB uses the SO PowerPAD-8 package (3.90 mm × 4.89 mm), featuring an exposed thermal pad (DAP) that must be soldered to a PCB ground plane using 4–6 thermal vias for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3404MR/NOPB, the LM3404HVMR/NOPB provides critical 75-V input tolerance for harsh automotive environments, while TPS92630QPWPRQ1 adds functional safety and digital control at the cost of increased complexity and non-pin-compatibility.

Availability

LM3404HVMR/NOPB is available at Aetrix Electronics and suitable for automotive lighting, industrial high-bay fixtures, and commercial streetlight systems requiring stable component supply, long-term manufacturability, and thermal reliability under continuous operation.

Supply support for LM3404HVMR/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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The LM3404HVMR/NOPB belongs to TI's high-voltage LED driver product line, engineered specifically for robust, thermally efficient constant-current regulation in demanding lighting applications where input transients, thermal stress, and long service life are critical.

FAQ

What is the maximum input voltage supported by the LM3404HVMR/NOPB?

The LM3404HVMR/NOPB supports a maximum input voltage of 75 V, as specified in its absolute maximum ratings and recommended operating conditions. This high-voltage capability enables use in 48 V industrial systems and automotive applications subject to load-dump transients. The standard LM3404MR/NOPB variant is limited to 42 V, making the HV version essential for designs requiring extended input range. Always observe derating guidelines per TI's thermal metrics documentation.

How does the LM3404HVMR/NOPB achieve constant LED current without external compensation?

The LM3404HVMR/NOPB uses a Controlled On-Time (COT) architecture that combines hysteretic current-mode control with a one-shot timer. By comparing the CS pin voltage against a precise 200-mV internal reference and modulating switch on-time based on VIN and RON, it maintains stable regulation without requiring external compensation components. This eliminates phase-margin analysis and simplifies design across temperature and component tolerances - a key advantage over traditional voltage-mode or current-mode controllers.

Can the LM3404HVMR/NOPB operate without an output capacitor?

Yes, the LM3404HVMR/NOPB is explicitly designed to support capacitor-less output configurations. Because it regulates LED current - not output voltage - the inductor and LED form a direct series path, eliminating the need for bulk output capacitance. TI's datasheet confirms stable operation with only a small 10-nF damping capacitor across the LED array to suppress ringing. This reduces bill-of-materials cost and board area, especially valuable in space-constrained lighting modules.

What thermal management is required for the LM3404HVMR/NOPB in continuous 1-A operation?

For continuous 1-A operation, the LM3404HVMR/NOPB requires PCB-level thermal management via its SO PowerPAD-8 package. The exposed DAP must be soldered to a solid ground plane with 4–6 thermal vias to the inner or bottom layer. TI specifies R_θJB = 24.5°C/W for this configuration. At 1-A load and 24-V input, typical power dissipation is ~0.75 W; maintaining junction temperature below 125°C requires ≤30°C/W total thermal resistance from junction to ambient - achievable with modest copper area and airflow.

Does the LM3404HVMR/NOPB support analog dimming, or only PWM dimming?

The LM3404HVMR/NOPB supports only digital PWM dimming via its dedicated DIM pin, which accepts TTL-level logic signals (V_IL ≤ 0.8 V, V_IH ≥ 2.2 V). It does not provide an analog dimming interface such as a variable current-sense reference or DAC-controlled bias. However, its fast enable/disable response (<1 µs) and internal 75-µA pullup ensure reliable low-frequency PWM dimming down to ~100 Hz without external components - ideal for flicker-free human-centric lighting control.