MAXREFDES1048: Two-layer circuit board, 3.3V/3A, wide input range, synchronous, step-down DC-DC converter

The MAX17504 high-efficiency, high-voltage, synchronously rectified step-down converter with dual integrated MOSFETs operates over a 4.5V to 60V input. The converter can deliver up to 3.5A and generates output voltage from 0.9V to 90% VIN. Built-in compensation across the output voltage range eliminates the need for external components. The feedback (FB) regulation is accurate to within ±1.1% over -40°C to +125°C. The devices are available in a compact (5mm x 5mm) TQFN lead (Pb)- free package with an exposed pad. Simulation models are available. The MAX17504 features a peak-current-mode control architecture with a MODE feature that can be used to operate the device in pulse-width modulation (PWM), pulse-frequency modulation (PFM), or discontinuous mode (DCM) control schemes.

PWM operation provides constant frequency operation at all loads and is useful in applications sensitive to switching frequency. PFM operation disables negative inductor current and skips pulses at light loads for high efficiency, allowing the DCM to feature constant frequency operation down to lighter loads than PFM mode. A programmable soft-start feature allows users to reduce input inrush current. The device also incorporates an output enable/ undervoltage lockout pin (EN/UVLO) that allows the user to turn on the part at the desired input voltage level. An open-drain RESET pin provides a delayed power-good signal to the system upon achieving successful regulation of the output voltage.

Key Features

• Eliminates External Components and Reduces Total Cost
• Reduces Number of DC-DC Regulators to Stock
• Reduces Power Dissipation
• Operates Reliably

This board is not available for purchase.

A small size, high-efficiency buck converter using the MAX17504 is demonstrated for a 3.3V/3A application.

Designed, Built, Tested

This document describes the hardware shown in Figure 1. It provides a detailed systematic technical guide to design in a high-efficiency buck converter using the MAX17504 step-down DC-DC converter. The power supply has been built and tested, details of which follow later in this document.

Design Resources