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High-Efficiency, PWM, Step-Down, N-Channel DC-DC Controller

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • 93% to 96% Efficiency for 50mA to 3A Output Currents
  • 4V to 15V Input Voltage Range
  • Low 950µA Supply Current
  • 1.4µA Shutdown Current
  • Drives External N-Channel FETs
  • Fixed-Frequency Current-Mode PWM (Heavy Loads)
  • Idle-Mode PFM (Light Loads)
  • Cycle-by-Cycle Current Limiting
  • 2V ±1.5% Accurate Reference Output
  • Adjustable Soft-Start
  • Undervoltage Lockout
  • Precision Comparator for Power-Fail or Low-Battery Warning

Applications/Uses

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

Description

The MAX746 is a high-efficiency, high-current, step-down DC-DC power-supply controller that drives external N-channel FETs. It provides 93% to 96% efficiency from a 6V supply voltage with load currents ranging from 50mA up to 3A. It uses a pulse-width-modulating (PWM) current-mode control scheme to provide precise output regulation and low output noise. The MAX746's 4V to 15V input voltage range, fixed 5V/adjustable (Dual-Mode™) output, and adjustable current limit make this device ideal for a wide range of applications.

High efficiency is maintained with light loads due to a proprietary automatic pulse-skipping control (Idle-Mode™) scheme that minimizes switching losses by reducing the switching frequency at light loads. The low 950µA quiescent current and ultra-low 1.4µA shutdown current further extend battery life.

External components are protected by the MAX746's cycle-by-cycle current limit. The MAX746 also features a 2V ±1.5% reference, a comparator for low-battery detection or level translating, and soft-start and shutdown capability.

The MAX747-discussed in a separate data sheet-functions similarly to the MAX746, but drives P-channel logic level FETs.

Simplified Block Diagram

MAX746: Typical Operating Circuit MAX746: 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.