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High-Efficiency, PWM, Step-Down Controller (External P-Channel Driver)

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • 90% to 95% Efficiency for 50mA to 2.5A Output Currents
  • 4V to 15V Input Voltage Range
  • Low 800µA Supply Current
  • 0.6µA Shutdown Current
  • Drives External P-Channel FETs
  • Cycle-by-Cycle Current Limiting
  • 2V ±1.5% Accurate Reference Output
  • Adjustable Soft-Start
  • Precision Comparator for Power-Fail or Low-Battery Warning

Applications/Uses

  • 5V to 3.3V Green PC Applications
  • Battery-Powered Applications
  • Cell Phones
  • Notebook Power Supplies
  • PDAs and Other Handheld Devices

Description

The MAX747 high-efficiency, high-current, step-down controller drives external P-channel FETs. It provides 90% to 95% efficiency from a 6V supply with load currents ranging from 50mA up to 2.5A. It uses a pulse-width-modulating (PWM) current-mode control scheme to provide precise output regulation and low output noise. The MAX747's 4V to 15V input voltage range, a fixed 5V/adjustable (Dual-Mode™) output, and a current limit set with an external resistor make this device ideal for a wide range of applications.

High efficiency is maintained with light loads due to a proprietary dual-control (Idle-Mode™) scheme that minimizes switching losses by reducing the switching frequency at light loads. The low 800µA quiescent current and ultra-low 0.6µA shutdown current further extend battery life.

External components are protected by the MAX747's cycle-by-cycle current limit. The MAX747 also features a 2V ±1.5% reference, a comparator for low-battery detection or level translating, as well as soft-start and shutdown capability.

The MAX746, discussed in a separate data sheet, functions similarly to the MAX747, but it drives N-channel logic level FETs on the high side.

Simplified Block Diagram

MAX747: Typical Operating Circuit MAX747: 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 .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.