Analog Devices Inc./Maxim Integrated MAX25239AFFA/VY+T

Overview

MAX25239AFFA/VY+T from Analog Devices is an automotive-grade synchronous buck-boost DC-DC converter with integrated H-bridge MOSFETs, delivering up to 6A continuous output current across a 2V–36V input range, supporting fixed 5V/11.5V or adjustable 3V–20V outputs, and operating from –40°C to +125°C for ADAS ECU power rails.

For engineers reviewing the MAX25239AFFA/VY+T datasheet, MAX25239AFFA/VY+T pinout, MAX25239AFFA/VY+T application, or MAX25239AFFA/VY+T equivalent, this device is selected for cold-crank resilient, spread-spectrum-enabled, AEC-Q100 Grade 1 point-of-load regulation where input voltage may fall below or exceed output - especially in infotainment and body electronics with strict quiescent current (<95μA) and EMI requirements.

Technical Context

The MAX25239AFFA/VY+T implements peak-current-mode control across three switching modes-buck, boost, and buck-boost-dynamically transitioning based on VIN/VOUT ratio using internally preset duty-cycle limits (DMAX = 0.73 for 2.1MHz variant). Its H-bridge architecture integrates four power MOSFETs with 20mΩ typical RDSON and supports 2.1MHz/400kHz/200kHz selectable frequencies.

It features a 1.8V internal LDO (VCC), programmable spread-spectrum (±6% modulation via SPS pin), open-drain PGOOD with 93%/94% thresholds, and dual thermal protection (175°C shutdown with 20°C hysteresis). The EN pin tolerates up to 42V, enabling direct battery connection without external level-shifting.

Key Specifications

Pinout & Package

MAX25239AFFA/VY+T is housed in a thermally enhanced 4.25mm × 4.25mm × 0.75mm, 22-pin FC2QFN package with exposed thermal pad (pin 22 = AGND), optimized for automotive PCB layouts requiring low θJA (33.3°C/W on JEDEC 4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX25239AFFA/VY+T, MAX20404ATPA/VY+ offers smaller footprint but lacks Grade 1 qualification and spread-spectrum; LM61480QRNTRQ1 delivers higher current but cannot operate in boost mode - making MAX25239AFFA/VY+T the only option among the three that fully supports automotive buck-boost use cases with AEC-Q100 compliance and EMI mitigation.

Availability

MAX25239AFFA/VY+T is available at Aetrix Electronics and suitable for ADAS ECU, infotainment systems, and start-stop auxiliary power supplies requiring stable component supply across extended temperature and automotive lifecycle demands.

Supply support for MAX25239AFFA/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 connectivity solutions.

The MAX25239AFFA/VY+T belongs to Analog Devices' automotive power management portfolio, designed specifically for robust, compact, and EMI-conscious DC-DC conversion in safety-critical vehicle subsystems operating across extreme voltage and temperature conditions.

FAQ

What is the maximum continuous output current supported by the MAX25239AFFA/VY+T?

The MAX25239AFFA/VY+T supports up to 6A continuous output current, subject to input-to-output voltage ratio, switching frequency, PCB thermal design, and ambient temperature. At 2.1MHz with 4-layer JEDEC board, 6A is achievable across 5V–12V outputs with VIN ≥ 8V; derating applies near input/output crossover or at elevated temperatures.

Does the MAX25239AFFA/VY+T support both fixed and adjustable output voltages?

Yes, the MAX25239AFFA/VY+T supports fixed 5V or 11.5V outputs (by connecting FB to VCC) and externally adjustable outputs from 3V to 20V (using resistor divider from OUT to AGND). The feedback reference voltage is tightly regulated at 0.800V ±1.75%, ensuring ±2% total output accuracy over line, load, and temperature.

How does the MAX25239AFFA/VY+T handle input voltage transients common in automotive environments?

The MAX25239AFFA/VY+T tolerates input transients up to 42V and features SUP undervoltage lockout (4.2V rising, 1.9V falling) and EN pin rated to 42V - enabling direct battery connection without external protection. Its 2V minimum operating input supports cold-crank conditions, and integrated cycle-by-cycle current limiting prevents damage during load dumps.

Can the MAX25239AFFA/VY+T be synchronized to an external clock, and what is the acceptable frequency range?

Yes, the MAX25239AFFA/VY+T can synchronize to an external clock applied to the SYNC pin. For the 2.1MHz variant, external clock must be within 1.5MHz–2.7MHz (±20%); for 400kHz variant, it must be 280kHz–520kHz. Synchronization occurs within two cycles, and the device reverts to internal oscillator if external clock is absent for >2 cycles.

What thermal protection mechanisms are built into the MAX25239AFFA/VY+T?

The MAX25239AFFA/VY+T includes thermal shutdown at 175°C with 20°C hysteresis and junction temperature monitoring per AEC-Q100. It also features thermal derating via reduced current limit above 125°C and uses a thermally enhanced 22-pin FC2QFN package with low θJCb (6.4°C/W) to maximize heat transfer to PCB ground plane.