Analog Devices Inc./Maxim Integrated MAX1540ETJ

Overview

MAX1540ETJ from Maxim Integrated is a dual step-down PWM controller IC designed for notebook computer power supplies, delivering two independent regulated outputs (1.8V/1.2V fixed or 0.7–5.5V adjustable on OUT1; 2.5V/1.5V fixed or 0.7–5.5V adjustable on OUT2) with 1% output accuracy, 2V–28V input range, and 170–620kHz selectable switching frequency. It integrates a fixed 5V/100mA linear regulator and provides inductor-saturation protection.

For engineers reviewing the MAX1540ETJ datasheet, MAX1540ETJ pinout, MAX1540ETJ application, or MAX1540ETJ equivalent, this page delivers verified technical context, validated pin functions, confirmed dual-output regulation behavior, real-world load-transient performance (100ns response), and accurate alternative part comparisons for notebook CPU/chipset and DDR memory supply designs.

Technical Context

The MAX1540ETJ implements Maxim's proprietary Quick-PWM™ architecture - a free-running, constant-on-time topology with input feed-forward - enabling ultra-fast transient response and wide VIN–VOUT differential operation. Its dual controllers operate independently with separate feedback (FB1/FB2), current-sense inputs (CSP1/CSN1, CSP2/CSN2), and gate drivers (DH1/DL1, DH2/DL2).

It supports valley-current limiting via external resistors, inductor-saturation detection using LSAT pin logic, and flexible startup control via ON1/ON2 enables. The integrated 5V LDO powers internal circuitry and can supply auxiliary loads up to 100mA, with dropout voltage ≤800mV at 50mA.

Key Specifications

Pinout & Package

MAX1540ETJ is housed in a 32-pin Thin QFN package (5mm × 5mm, 0.5mm pitch), thermally enhanced with exposed pad. Pin assignment follows standard Maxim step-down controller layout with dual high-side/low-side driver pairs, independent feedback and current-sense inputs, and dedicated enable/control pins.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual step-down controller applications.

Compared with MAX1541ETL and TPS51220ARUKR, MAX1540ETJ offers fixed dual outputs with integrated 5V LDO and proven inductor-saturation protection - ideal for cost-optimized, production-ready notebook platforms where VCORE dynamic adjustment is not required.

Availability

MAX1540ETJ is available at Aetrix Electronics and suitable for notebook computer power management, CPU/chipset core supplies, and DDR memory termination applications requiring stable component supply, long-term lifecycle support, and full traceability.

Supply support for MAX1540ETJ 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) designs high-performance analog and mixed-signal ICs for power management, data conversion, and interface applications.

The MAX1540 product line targets high-efficiency, compact DC-DC conversion in portable computing - specifically engineered for dual-rail, battery-powered systems demanding fast transient response and integrated protection features.

FAQ

What is the input voltage range supported by the MAX1540ETJ?

The MAX1540ETJ supports an input voltage range of 2V to 28V, enabling compatibility with single- to multi-cell Li-ion batteries and wide industrial input rails. This range allows direct connection to 3-cell (up to ~12.6V) or 4-cell (up to ~16.8V) battery packs, as well as higher-voltage auxiliary supplies. The MAX1540ETJ maintains regulation and protection functionality across this full span without external components.

Does the MAX1540ETJ include an integrated linear regulator?

Yes, the MAX1540ETJ integrates a fixed 5V, 100mA linear regulator (LDO) with ±2% output accuracy and dropout voltage ≤800mV at 50mA. The LDO output (LDOOUT) powers internal circuitry and can supply external loads such as voltage references or level-shifters. Its input (LDOIN) is internally tied to the main battery input (V+), simplifying system power architecture.

How does the MAX1540ETJ achieve ultra-fast load transient response?

The MAX1540ETJ achieves 100ns load-step response using Maxim's Quick-PWM™ architecture - a free-running, constant-on-time control scheme with input feed-forward. This eliminates loop compensation delays and enables immediate duty-cycle adjustment in response to output current changes. The MAX1540ETJ sustains this performance across its full 0.7V–5.5V output range and 2V–28V input range without tuning.

What protection features are built into the MAX1540ETJ?

The MAX1540ETJ includes inductor-saturation protection (via LSAT pin), valley-current limiting (via CSP/CSN inputs), overvoltage/undervoltage fault detection (OVP/UVP pin), and thermal shutdown (160°C threshold). It also provides power-good monitoring (PGOOD1/PGOOD2) with ±10% windows and 10µs propagation delay. These features ensure robust operation during fault conditions without external supervision circuitry.

Can the MAX1540ETJ be used for DDR memory VTT termination?

Yes, the MAX1540ETJ is suitable for DDR memory VTT termination. Its adjustable output range (0.7V–5.5V), 1% accuracy, and differential current-sense inputs allow precise VTT regulation (e.g., 0.9V or 1.25V) with excellent load transient response. When configured with appropriate external resistors and output capacitors, the MAX1540ETJ meets JEDEC VTT specifications for DDR2/DDR3 termination rails.