Analog Devices Inc./Maxim Integrated MAX20051AUD/V+T

Overview

MAX20051AUD/V+T from Analog Devices is a 2A synchronous-buck LED driver IC for automotive exterior lighting, featuring integrated 0.14Ω (typ) high- and low-side MOSFETs, 400kHz fixed switching frequency, external loop compensation, and high-side current regulation. It operates from 4.5V to 65V input, delivers ±2.5% full-scale current accuracy over –40°C to +125°C, and supports PWM + analog (REFI) dimming in DRLs and headlamps.

For engineers reviewing the MAX20051AUD/V+T datasheet, MAX20051AUD/V+T pinout, MAX20051AUD/V+T application, or MAX20051AUD/V+T equivalent, key selection considerations include its AEC-Q100 qualification, 12-pin 3mm × 3mm TDFN package with exposed pad, 200mV high-side current-sense threshold, 5V/10mA LDO output, and fault protection including open-LED, short-circuit, and thermal shutdown.

Technical Context

The MAX20051AUD/V+T implements average-current-mode control using a transconductance error amplifier whose output appears on the COMP pin for external RC compensation. Its 400kHz oscillator synchronizes to the rising edge of the PWM dimming signal, enabling precise low-duty-cycle dimming without phase jitter.

High-side sensing via CS+/CS– enables single-wire LED string connection with local grounding; the 200mV full-scale sense voltage minimizes power loss while supporting ±8% current accuracy at 10% load. Spread spectrum is disabled in this B-version variant, distinguishing it from MAX20051 (non-B) and MAX20053 variants.

Key Specifications

Pinout & Package

MAX20051AUD/V+T is housed in a thermally enhanced 12-pin (3mm × 3mm) TDFN package with exposed pad (EP), optimized for high-power automotive LED driver applications requiring compact layout and efficient heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX20051AUD/V+T, the TSSOP variant trades thermal performance for assembly flexibility, while the 2.1MHz MAX20053ATP/V+T reduces passive size at the cost of stricter EMI filtering - neither is pin-compatible due to differing package footprints and thermal pad configurations.

Availability

MAX20051AUD/V+T is available at Aetrix Electronics and suitable for automotive exterior lighting, commercial LED signage, and industrial machine vision illumination requiring stable component supply, AEC-Q100 compliance, and high-reliability thermal management.

Supply support for MAX20051AUD/V+T 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

Analog Devices is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for automotive, industrial, and communications markets.

The MAX20050–MAX20053 family was designed specifically for automotive exterior LED lighting, delivering integrated power stage, precision current regulation, and robust fault protection in thermally optimized packages.

FAQ

What is the switching frequency of the MAX20051AUD/V+T and is it adjustable?

The MAX20051AUD/V+T operates at a fixed 400kHz switching frequency with no dithering - this is a defining characteristic of the "B" version (MAX20051B). Unlike the non-B MAX20051, spread spectrum is disabled, and the frequency cannot be adjusted via external components or synchronization signals. The 400kHz value is factory-trimmed and remains stable across temperature and input voltage.

Does the MAX20051AUD/V+T support both PWM and analog dimming simultaneously?

Yes, the MAX20051AUD/V+T supports concurrent PWM and analog dimming: the REFI pin sets the maximum current level (0–100%), while the PWM pin controls duty cycle (0–100%) within that ceiling. For example, with REFI = 0.6V (50% max current) and 80% PWM duty, the effective LED current is 40% of full scale. This dual-control enables fine-grained brightness tuning in adaptive lighting systems.

What fault conditions does the FLT pin indicate on the MAX20051AUD/V+T?

The FLT pin on the MAX20051AUD/V+T asserts low for three confirmed fault conditions: LED open-circuit (detected when REFI voltage exceeds 325mV while VIN > 9V), output short-circuit (when CS– voltage falls below 1.5V), and junction overtemperature (>165°C). Each fault includes built-in deglitching (105µs) and mask timers (210ms) to prevent false triggering during startup or transient events.

Can the MAX20051AUD/V+T drive LED strings with forward voltages exceeding the input supply?

No - the MAX20051AUD/V+T is a buck (step-down) converter only and cannot drive LED strings whose total forward voltage exceeds the input supply voltage. Its maximum output voltage is limited to VIN minus dropout losses (typically < VIN – 1.5V). For boost or buck-boost topologies, consider Analog Devices' MAX20078 or MAX2560x families instead of the MAX20051AUD/V+T.

What is the purpose of the COMP pin on the MAX20051AUD/V+T and how is it used?

The COMP pin on the MAX20051AUD/V+T provides access to the output of the internal transconductance error amplifier, enabling external Type-II or Type-III compensation networks. Designers connect an RC network from COMP to AGND to stabilize the current-loop across varying LED Vf and temperature - this flexibility is essential for maintaining phase margin in high-Vf automotive LED strings (e.g., 6× 20V white LEDs).