Analog Devices Inc./Maxim Integrated MAX25239AFFD/VY+T

Overview

MAX25239AFFD/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 and supporting fixed (5V/11.5V) or adjustable (3V–20V) output voltage. It operates in buck, boost, or buck-boost mode automatically based on VIN/VOUT ratio and features 2.1MHz/400kHz/200kHz selectable switching frequency, 95μA standby quiescent current, and AEC-Q100 Grade 1 qualification for ADAS ECU and start-stop systems.

For engineers reviewing the MAX25239AFFD/VY+T datasheet, MAX25239AFFD/VY+T pinout, MAX25239AFFD/VY+T application, or MAX25239AFFD/VY+T equivalent, key selection criteria include input transient tolerance (42V), EN pin voltage rating (up to 42V), PGOOD monitoring accuracy (±1% VOUT threshold), thermal shutdown (175°C), and spread-spectrum EMI reduction (±6%).

Technical Context

The MAX25239AFFD/VY+T implements peak-current-mode control with automatic transition between buck, boost, and buck-boost operating modes determined by VIN/VOUT ratio and internally preset duty-cycle limits (DMAX = 0.73 for 2.1MHz variant). Its H-bridge architecture uses four integrated DMOS switches (HS1/LS1/HS2/LS2) with 20mΩ typical RDS(ON), enabling seamless regulation when input crosses output voltage.

It integrates a 1.8V linear regulator (VCC) powered from SUP or OUT, supports three SYNC-controlled operation modes (skip, FPWM, external clock sync), and includes programmable spread-spectrum modulation (enabled via SPS pin) to reduce radiated EMI without requiring external filtering components.

Key Specifications

Pinout & Package

MAX25239AFFD/VY+T is housed in a thermally enhanced 22-pin FC2QFN package (4.25mm × 4.25mm × 0.75mm) with exposed thermal pad. The pinout matches the MAX25239AFF variant per Analog Devices' Pin Configurations diagram (Rev 14, p.12).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX25240AFFD/VY+T and LM61480QRNTRQ1, the MAX25239AFFD/VY+T uniquely combines 2.1MHz operation, ±6% spread spectrum, AEC-Q100 Grade 1, and true 2V cold-crank capability in a pin-compatible 22-pin FC2QFN - enabling smaller, quieter, and more robust automotive power designs without layout changes.

Availability

MAX25239AFFD/VY+T is available at Aetrix Electronics and suitable for ADAS ECU, infotainment systems, and start-stop battery management requiring stable component supply across extended temperature and voltage ranges.

Supply support for MAX25239AFFD/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.

The MAX25239/MAX25240 product line delivers highly integrated, AEC-Q100-qualified buck-boost converters optimized for automotive power architectures demanding cold-crank operation, low quiescent current, and EMI robustness.

FAQ

What is the maximum continuous output current supported by the MAX25239AFFD/VY+T?

The MAX25239AFFD/VY+T supports up to 6A continuous output current, but actual deliverable current depends on input-to-output voltage ratio, ambient temperature, PCB copper area, and switching frequency. At 2.1MHz and VIN = 14V → VOUT = 5V, thermal limits typically allow ~5.2A in a 4-layer JEDEC board layout. Derating is required above +85°C ambient or with poor thermal vias.

Does the MAX25239AFFD/VY+T require external MOSFETs or gate drivers?

No, the MAX25239AFFD/VY+T integrates all four power MOSFETs (HS1/LS1/HS2/LS2) and their gate drivers within the 22-pin FC2QFN package. This eliminates the need for external high-side/low-side switches, bootstrap diodes, and discrete drivers - reducing total solution size and simplifying layout while maintaining 20mΩ typical RDS(ON).

How does the MAX25239AFFD/VY+T handle input voltage transients up to 42V?

The MAX25239AFFD/VY+T tolerates 42V transients on SUP and EN pins per Absolute Maximum Ratings (p.5), with internal clamping and robust oxide design. Its 2V–36V operating range ensures functionality during cold-crank (down to 2.2V), while the 42V rating covers ISO 7637-2 Pulse 5a load-dump events - eliminating need for external TVS diodes in most automotive front-end designs.

Can the MAX25239AFFD/VY+T be synchronized to an external clock source?

Yes, the MAX25239AFFD/VY+T supports external clock synchronization via the SYNC pin. When driven with a clean CMOS-level clock (min pulse width 100ns), it locks its internal oscillator to the external frequency within ±20% range using a PLL architecture, completing sync in two cycles. During loss of external clock, it automatically reverts to internal timing without glitch.

What is the purpose of the SPS pin on the MAX25239AFFD/VY+T?

On the MAX25239AFFD/VY+T, the SPS (Spread-Spectrum) pin enables or disables ±6% frequency modulation of the switching clock to reduce peak radiated EMI. When pulled high, spread spectrum is active; when low, fixed-frequency operation resumes. Note that SPS is automatically disabled during external clock synchronization to preserve timing integrity.