Texas Instruments LM3402HVMR/NOPB

Overview

LM3402HVMR/NOPB from Texas Instruments is a monolithic 0.5-A constant-current buck regulator with integrated 735-mA 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 precise 200-mV current-sense threshold regulation, supports PWM dimming via TTL-compatible DIM pin, and features hysteretic controlled ON-time architecture eliminating loop compensation.

For engineers reviewing the LM3402HVMR/NOPB datasheet, LM3402HVMR/NOPB pinout, LM3402HVMR/NOPB application, or LM3402HVMR/NOPB equivalent, key selection considerations include its 75-V max input rating, 300-ns minimum OFF-time limiting VO(MAX), thermal shutdown at 165°C, and RON-programmable switching frequency - all critical for robust LED driver design in harsh environments.

Technical Context

The LM3402HVMR/NOPB implements a Controlled ON-Time (COT) architecture combining hysteretic current sensing with a one-shot timer whose duration scales inversely with VIN and is set by external RON. This enables stable constant-current regulation without compensation components while maintaining near-constant switching frequency in continuous conduction mode (CCM).

Its internal 7-V linear regulator powers gate drive and control circuitry from VIN, with UVLO at 5.25 V and bypass threshold at 8.8 V. The high-side MOSFET driver uses a bootstrap capacitor (CB) referenced to SW, enabling operation up to 75 V input while sustaining fast 20-ns rise/fall times and 3-nC gate charge.

Key Specifications

Pinout & Package

LM3402HVMR/NOPB is housed in an 8-pin HSOP (DDA) package measuring 4.89 mm × 3.90 mm with exposed thermal pad (DAP) for enhanced thermal performance. The DAP must be soldered to PCB ground plane using 4–6 thermal vias.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3402MR/NOPB, the LM3402HVMR/NOPB enables operation in 48-V industrial and 75-V load-dump automotive systems, while TPS92630QPWPRQ1 adds AEC-Q100 qualification and diagnostics at the expense of higher BOM cost and non-drop-in layout changes.

Availability

LM3402HVMR/NOPB is available at Aetrix Electronics and suitable for automotive headlamps, industrial high-bay lighting, and outdoor streetlight systems requiring stable component supply across extended temperature and voltage ranges.

Supply support for LM3402HVMR/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 applications.

The LM3402HV product line delivers high-voltage, constant-current buck regulators optimized for reliable, compact LED driver designs in harsh environments - emphasizing input voltage resilience, thermal robustness, and system-level fault protection.

FAQ

What is the maximum input voltage supported by the LM3402HVMR/NOPB?

The LM3402HVMR/NOPB supports a maximum input voltage of 75 V, as specified in its absolute maximum ratings and recommended operating conditions. This rating enables use in 48-V industrial systems and automotive applications subject to load dump transients. Operation above 75 V risks permanent damage; the device includes internal protection but is not rated for sustained overvoltage beyond this limit. Always verify input rail transient behavior in final system design.

How does the LM3402HVMR/NOPB achieve constant-current regulation without external compensation?

The LM3402HVMR/NOPB uses a Controlled ON-Time (COT) architecture that combines hysteretic current sensing at the CS pin with a one-shot timer whose duration is set by RON and VIN. This eliminates the need for traditional voltage-mode or current-mode loop compensation components. The 200-mV CS threshold directly regulates LED current, while the fixed 300-ns minimum OFF-time and VIN-scaled ON-time maintain stability across input and load variations - verified in TI's SNVS450F datasheet Section 7.1.

Can the LM3402HVMR/NOPB drive LED strings without an output capacitor?

Yes, the LM3402HVMR/NOPB supports capacitor-less LED driving, as confirmed in Section 8.1.3 of the SNVS450F datasheet. Its constant-current topology inherently controls LED current ripple via inductor selection and switching frequency, removing the need for output capacitance to stabilize voltage. A small 10-nF capacitor across the LED array is recommended to dampen SW-node oscillation during open-circuit events, but bulk CO is optional and system-dependent.

What thermal performance can be expected from the LM3402HVMR/NOPB in an HSOP package?

In the HSOP (DDA) package, the LM3402HVMR/NOPB achieves a junction-to-board thermal resistance (RθJB) of 25.8°C/W, enabling >1.5 W power dissipation on a standard 2-layer PCB with DAP-to-ground vias. With proper thermal pad layout (4–6 vias to inner ground plane), it sustains 500-mA LED current at 125°C junction temperature under 24-V input. Thermal shutdown activates at 165°C with 25°C hysteresis, providing robust overtemperature protection without latch-up.

Does the LM3402HVMR/NOPB support PWM dimming, and what are the interface requirements?

Yes, the LM3402HVMR/NOPB supports TTL-compatible PWM dimming via its DIM pin, which accepts logic-high ≥2.2 V and logic-low ≤0.8 V. An internal 75-µA pullup ensures default-on operation when DIM is left floating. Dimming frequency should be at least one decade below the converter's switching frequency to prevent aliasing; the datasheet recommends fDIM < fSW/10. No external pullup resistor is needed, simplifying microcontroller interface.