MAX1549

19-3165; Rev 0; 1/04 KIT ATION EVALU E L B AVAILA www.DataSheet4U.com Dual, Interleaved, Fixed-Frequency Step-Down Controller with a Dynamically Adjustable Output General Description The MAX1549 dual pulse-width modulation (PWM) stepdown controller provides the high efficiency, excellent transient response, and high DC-output accuracy necessary for generating low-voltage chipset and RAM power supplies in notebook computers. 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 MAX1549 features differential current-sense inputs for accurately sensing the inductor current across an external current-sense resistor in series with the output to ensure reliable overload protection. Alternatively, the controller can provide overload protection using lossless inductor current-sensing methods, lowering power dissipation and reducing system cost. Single-stage buck conversion allows the MAX1549 to directly step down high-voltage batteries for the highest possible efficiency. Very low output-voltage applications require two-stage conversion—stepping down from another system supply rail instead of the battery. The MAX1549 powers chipsets and graphics processor cores that require dynamically adjustable output voltages, or generates the active termination bus that must track the input reference. The main step-down contr...