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High-Accuracy Step-Down Controller with Synchronous Rectifier for CPU Power

High-Efficiency Over Wide Load Range

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • 96% Efficiency
  • 4.5V to 30V Input Range
  • 1.6V to 6V Adjustable Precision Output
  • ±0.4% Max Total Load-Regulation Error
  • 0.06%/V Max Line-Regulation Error
  • 5V Linear-Regulator Output
  • Precision 2.505V Reference Output
  • Automatic Bootstrap Circuit
  • 150kHz/300kHz Fixed-Frequency PWM Operation
  • Programmable Soft-Start
  • 1.2mA Typical Quiescent Current (VIN = 12V, VOUT = 2.5V)
  • 1µA Typical Shutdown Current

Applications/Uses

  • Notebook and Subnotebook Computers
  • PDAs and Mobile Communicators

Description

The MAX798 high-performance, step-down DC-DC converter provides main CPU power in battery-powered systems. This buck controller achieves 96% efficiency by using synchronous rectification and Maxim's proprietary Idle Mode™ control scheme to extend battery life at full-load (up to 10A) and no-load outputs. The MAX798's high accuracy meets the demanding requirements of the latest-generation CPUs. Excellent dynamic response corrects output transients caused by the latest dynamic-clock CPUs within five 300kHz clock cycles. Unique bootstrap circuitry drives inexpensive N-channel MOSFETs, reducing system cost and eliminating the crowbar switching currents found in some PMOS/NMOS switch designs.

The MAX798 has a logic-controlled and synchronizable fixed-frequency pulse-width-modulating (PWM) operating mode, which reduces noise and RF interference in sensitive mobile-communications and pen-entry applications. The SKIP override input allows automatic switchover to idle-mode operation (for high-efficiency pulse skipping) at light loads, or forces fixed-frequency mode for lowest noise at all loads.

Simplified Block Diagram

MAX798: Typical Operating Circuit MAX798: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .