MAXREFDES1033: 3A/3.3V and 3A/5V, single-phase, dual-output, synchronous, step-down DC-DC converter

The MAX17509 integrates two 3A internal switch step-down regulators with programmable features. The device can be configured as two single-phase, independent, 3A power supplies or as one dual-phase, single-output 6A power supply. It operates from a 4.5V to 16V input and generates independently adjustable output voltage in the ranges of 0.904V to 3.782V and 4.756V to 5.048V, with ±2% system accuracy. This device provides maximum flexibility to the end user by allowing one to choose multiple programmable options by connecting resistors to the configuration pins. Two key highlights of the device are the self-configured compensation for any output voltage and the ability to program the slew rate of LX switching nodes to mitigate noise and EMI concerns. Noise-sensitive applications, such as high-speed multi-gigabit transceivers in FPGAs, RF, and audio applications, can benefit from this unique slew-rate control. SYNC input is provided for synchronized operation of multiple devices with system clocks.

The MAX17509 offers output overvoltage (OV) and undervoltage (UV) protection, as well as overcurrent (OC) and undercurrent (UC) protection with a selectable hiccup/latch option. Main features include the following:

Key Features

• Reduces Number of DC-DC Regulators in Inventory
• Output Voltage (0.904V to 3.782V and 4.756V to 5.048V with 20mV Resolution)
• Configurable Two Independent Outputs (3A/3A) or a Dual-Phase Single Output (6A)
• Mitigates Noise Concerns and EMI
• Adjustable Switching Frequency with Selectable 0/180° Phase Shift
• External Frequency Synchronization
• Adjustable Switching Slew Rate
• Passes EN55022 (CISPR22) Class-B Radiated and Conducted EMI Standard
• Ease of System Design
• All Ceramic Capacitors Solution
• Auto-Configured Internal Compensation Selectable Hiccup or Brick-Wall Mode
• Adjustable Soft-Start Rise/Fall Time with Soft-Stop Modes and Prebias Startup

This board is not available for purchase.

A dual-output buck converter using the MAX17509 is demonstrated for a 3.3V and 5V DC output application. The power supply delivers up to 3A at 3.3V and up to 3A at 5V.

Designed, Built, Tested

This document describes the hardware shown in Figure 1. It provides a detailed systematic technical guide to design in a dual-output buck converter using Maxim’s MAX17509 step-down DC-DC converter. The power supply has been built and tested, details of which follow later in this document.

Design Resources