Analog Devices Inc./Maxim Integrated MAX20408AFOB/VY+T

Overview

MAX20408AFOB/VY+T from Analog Devices is an automotive-grade, fully integrated synchronous buck converter with internal high-side and low-side MOSFETs, delivering up to 8A output current from a 3.0V–36V input. It features 10μA quiescent current in skip mode, 2.1MHz/400kHz selectable switching frequency, ±1% output voltage accuracy (E-version), and AEC-Q100 qualification for use in ADAS power rails.

For engineers reviewing the MAX20408AFOB/VY+T datasheet, MAX20408AFOB/VY+T pinout, MAX20408AFOB/VY+T application, or MAX20408AFOB/VY+T equivalent, key selection criteria include dual-phase scalability to 20A, 34ns minimum on-time for high VIN/VOUT ratios, windowed PGOOD with 102.75–107.25% rising/falling thresholds, and FC2QFN-17 package thermal performance (θJB = 9.9°C/W on EV kit).

Technical Context

The MAX20408AFOB/VY+T implements average current-mode control with 34ns minimum on-time, enabling stable operation across wide input-output differentials (e.g., 24V→3.3V). Its dual-phase capability uses VEA pin coupling and SYNCOUT-to-SYNC interconnection to achieve 180° out-of-phase operation and dynamic current sharing between controller and target ICs.

It integrates a 1.8V BIAS linear regulator with 2.2μF output capacitance requirement, supports forced-PWM, skip-mode, and external clock synchronization via the SYNC pin, and includes spread-spectrum modulation (±3% fSW) to reduce EMI-disabled only when externally synchronized.

Key Specifications

Pinout & Package

MAX20408AFOB/VY+T is housed in a thermally enhanced 3.5mm × 3.75mm, 17-pin FC2QFN package with exposed thermal pad (pin 16), symmetric SUP/PGND pin placement for balanced current loops, and RoHS-compliant matte-tin finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck converter applications.

Compared with MAX20404AFOB/VY+T, the MAX20408AFOB/VY+T delivers double the current and dual-phase capability at identical board area; versus TPS62933RGER, it adds AEC-Q100, windowed PGOOD, and superior thermal performance (9.9°C/W vs. ~15°C/W), justifying its use in safety-critical ADAS power stages.

Availability

MAX20408AFOB/VY+T is available at Aetrix Electronics and suitable for automotive ADAS camera modules, infotainment SoC core supplies, and radar transceiver bias rails requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.

Supply support for MAX20408AFOB/VY+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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets with precision power, sensing, and signal chain solutions.

The MAX20408/MAX20410 family is designed specifically for demanding automotive power applications-including ADAS, infotainment, and body electronics-where ultra-low IQ, high current density, and AEC-Q100 reliability are mandatory.

FAQ

What is the maximum output current capability of the MAX20408AFOB/VY+T?

The MAX20408AFOB/VY+T delivers up to 8A continuous output current under typical conditions (TA = +85°C, 4-layer EV kit). Its 99% maximum duty cycle and 34ns minimum on-time support high step-down ratios, and dual-phase configuration with a second MAX20408AFOB/VY+T enables up to 20A total output with matched current sharing and 180° phase interleaving.

Does the MAX20408AFOB/VY+T support both fixed and adjustable output voltages?

Yes, the MAX20408AFOB/VY+T supports both configurations. For adjustable output, connect FB to a resistor divider between OUT and GND (0.8V–10V range at 400kHz, 0.8V–6V at 2.1MHz). For fixed output, tie FB directly to BIAS; the MAX20408E variant offers factory-set 3.3V, 4V, or 5V options with ±1% accuracy and windowed PGOOD thresholds.

How does the PGOOD function differ between standard and E-version variants of the MAX20408AFOB/VY+T?

The MAX20408AFOB/VY+T is an E-version part, featuring windowed PGOOD with asymmetric rising (102.75–107.25%) and falling (101.75–106.25%) thresholds-significantly tighter than the standard version's 92–96% window. This enables precise overvoltage detection critical for protecting downstream SoCs and sensors in ADAS systems.

What thermal performance can be expected from the MAX20408AFOB/VY+T in a real PCB layout?

On a 4-layer evaluation kit, the MAX20408AFOB/VY+T achieves θJB = 9.9°C/W and θJA = 27°C/W. This allows 8A continuous operation at +85°C ambient with no airflow. The FC2QFN-17 package's exposed thermal pad and symmetric SUP/PGND pinout minimize thermal resistance and improve EMI performance simultaneously.

Can the MAX20408AFOB/VY+T be synchronized to an external clock, and what frequency range is supported?

Yes, the MAX20408AFOB/VY+T accepts external clock signals on the SYNC pin across two ranges: 360–600kHz when configured for 400kHz operation, and 1.7–2.6MHz when configured for 2.1MHz operation. External synchronization disables internal spread-spectrum but passes any modulation present on the driving clock source.