DUAL, INTERLEAVED, FIXED-FREQUENCY STEP-DOWN CONTROLLER WITH A DYNAMICALLY ADJUSTABLE OUTPUT
SUNNYVALE, CA-February 13, 2004-Maxim Integrated Products
(NASDAQ: MXIM) introduces the MAX1549, a dual, pulse-width modulation (PWM) step-down controller that provides high efficiency, excellent transient response, and high DC-output accuracy necessary for generating low-voltage chipset and RAM power supplies in notebook computers. Single-stage buck conversion allows the device to directly step down high-voltage batteries for the highest possible efficiency. Low-output voltage applications require two-stage conversion-stepping down from another system supply rail instead of the battery. The controller employs a fixed-frequency, current-mode PWM architecture that does not require complex compensation. The MAX1549 also interleaves the dual step-down regulators, minimizing the input capacitor requirements.
The proprietary Quick-PWM™ controllers are free running and have constant on-time with input feed-forward. This configuration provides ultra-fast transient response, wide input-output differential range, low supply current, and tight load-regulation characteristics. The controllers accurately sense the inductor current across an external current-sense resistor in series with the output to ensure reliable overload and inductor-saturation protection. Alternatively, the controllers can use the synchronous rectifier itself or lossless inductor current-sensing methods to provide overload protection with lower power dissipation.
The MAX1549 is available in a 40-pin TQFN package with optional inductor-saturation protection, and overvoltage/undervoltage protection. It is screened for the extended temperature range (-40°C to +85°C). Prices start at $3.75 (1000-up, FOB USA). An evaluation kit is available with recommended external components to speed designs.
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
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