Analog Devices Inc./Maxim Integrated MAX8744AETJ+T

Overview

MAX8744AETJ+T from Maxim Integrated is a dual step-down, synchronous switch-mode power-supply (SMPS) controller with integrated 5V linear regulator and auxiliary LDO driver, designed for main 5V/3.3V generation in notebook computers. It supports 6V–26V input, delivers fixed or adjustable 3.3V/5V outputs with ±0.75% reference accuracy, and features 40/60° interleaving to minimize input ripple down to 8.3V input.

For engineers reviewing the MAX8744AETJ+T datasheet, MAX8744AETJ+T pinout, MAX8744AETJ+T application, or MAX8744AETJ+T equivalent, key selection criteria include its quad-output capability (3.3V, 5V, 12V/adjustable, keep-alive), overvoltage-fault protection (MAX8744A-specific), 8µA shutdown current, and 32-pin 5mm × 5mm thin QFN package with exposed thermal pad.

Technical Context

The MAX8744AETJ+T implements fixed-frequency, current-mode control with programmable switching frequencies (200/300/500 kHz) and 40/60° phase shift between SMPS3 and SMPS5 - enabling lower minimum input voltage before duty-cycle overlap versus 180° interleaved regulators. Its Dual Mode™ feedback allows seamless transition between fixed 3.3V/5V and adjustable 2.0V–5.5V output configurations using the same FB pins.

It integrates three independent power rails: an internal 5V/100mA LDO (bypassed to 200mA during regulation), an auxiliary linear-regulator driver (DRVA/FBA) supporting external PNP-based 12V or sub-1V outputs, and a precision 2.00V ±10mV reference (REF) with 50µA drive capability. Fault protection includes undervoltage, thermal, and - uniquely for MAX8744A - output overvoltage detection with 10µs propagation delay.

Key Specifications

Pinout & Package

MAX8744AETJ+T is housed in a 32-pin, 5mm × 5mm thin QFN package with an exposed backside thermal pad connected to GND. The package supports high-current gate driving and efficient heat transfer in space-constrained notebook power designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output synchronous buck controller applications.

Compared with MAX8745AETJ+, the MAX8744AETJ+ adds critical overvoltage protection for safety-critical notebook rails; compared with RT8209MZQW, it delivers greater flexibility via Dual Mode™ feedback, auxiliary LDO control, and precision 2V reference - justifying its use in premium mobile platforms.

Availability

MAX8744AETJ+T is available at Aetrix Electronics and suitable for notebook computer main power supplies, subnotebook battery management systems, and mobile communicator power architectures requiring stable component supply, full production traceability, and long-term lifecycle support.

Supply support for MAX8744AETJ+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

Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for computing, communications, and industrial applications.

The MAX8744AETJ+T belongs to Maxim's notebook power-controller product line, engineered specifically to consolidate multiple voltage rails, sequencing, and protection functions into a single compact QFN package for space- and efficiency-constrained mobile platforms.

FAQ

What is the key functional difference between MAX8744AETJ+T and MAX8745AETJ+?

The MAX8744AETJ+T includes output overvoltage-fault protection for both 3.3V and 5V rails - a feature absent in the MAX8745AETJ+. This protection triggers at +11% over nominal voltage with 10µs propagation delay, safeguarding downstream logic in notebook systems. All other electrical specifications, pinout, and packaging are identical between the two parts.

Does MAX8744AETJ+T support adjustable output voltages, and how is it configured?

Yes, MAX8744AETJ+T supports adjustable 3.3V and 5V outputs via its Dual Mode™ feedback architecture. When FB3 or FB5 is disconnected from LDO5 and routed to a resistive divider, the controller regulates to 2.00V ±10mV at the FB pin - enabling output ranges from 2.0V to 5.5V. The threshold for mode switching is VLDO5 − 0.4V, ensuring reliable transition between fixed and adjustable modes.

How does the 40/60° interleaving in MAX8744AETJ+T improve system performance compared to standard 180° interleaving?

The 40/60° interleaving in MAX8744AETJ+T reduces input ripple current amplitude by over 50% versus 180° phase shift and extends the minimum usable input voltage to 8.3V before duty-cycle overlap occurs - whereas 180° interleaved regulators fail below 10V. This enables longer battery runtime in low-VIN states and allows smaller input capacitors in notebook designs.

Can MAX8744AETJ+T generate a 12V auxiliary output, and what external components are required?

Yes, MAX8744AETJ+T can generate a 12V auxiliary output using its DRVA pin and external PNP transistor. Connect DRVA to the base of a PNP power transistor (e.g., MMBT3906), add a 680Ω resistor between base and emitter, and tie the collector to VIN and emitter to the 12V output. FBA senses the output and regulates it to match V_DRVA − V_BE, enabling precise 12V generation.

What thermal management provisions does MAX8744AETJ+T include for high-power notebook applications?

MAX8744AETJ+T uses a 32-pin thin QFN package with an exposed backside thermal pad that must be soldered to the PCB ground plane. This pad significantly lowers junction-to-board thermal resistance, enabling continuous operation at full load in ambient temperatures up to +85°C. The device also includes thermal-shutdown protection at +160°C with 15°C hysteresis to prevent permanent damage during overload conditions.