MAXREFDES1130: Low output voltage ripple design using MAX17509 integrated switch, 0.9V/2A and 1.2V/2A dual-output step-down DC-DC converter

The MAX17509 integrates two internal switch step-down regulators with programmable features. The device can be configured as two single-phase independent power supplies or as a dual-phase, single-output power supply. The device operates from 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. The MAX17509 provides maximum flexibility to end-users by allowing them 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 concerns. Noise-sensitive applications, such as high-speed multigigabit transceivers in FPGAs, RF, and audio, 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.

Key Features

• Reduces Number of DC-DC Regulators in Inventory
• Output Voltage of 0.904V to 3.782V and 4.756V to 5.048V with 20mV Resolution
• Configurable Two Independent Outputs or a Dual-Phase Single Output
• Mitigate 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
• Autoconfigured Internal Compensation Selectable Hiccup or Brick-Wall Mode
• Adjustable Soft-Start Rise/Fall Time with Soft-Stop Modes and Pre-Bias Startup

This board is not available for purchase.

A dual output buck converter using the MAX17509 is demonstrated for a 0.9V and 1.2V output application. The power supply delivers up to 2A at 0.9V and up to 2A at 1.2V.

Designed, Built, Tested

This document describes the hardware. 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