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Notebook CPU Step-Down Controller

Product Details

Key Features

Simplified Block Diagram

Technical Docs

Data Sheet Notebook CPU Step-Down Controller Dec 09, 2008

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Key Features

  • Quick-PWM Architecture
  • ±1% VOUT Accuracy Over Line and Load
  • 5-Bit On-Board DAC with Input Muxes
  • Precision-Adjustable VOUT Slew Control
  • 0.6V to 1.75V Output Adjust Range
  • Precision Offset Control
  • Supports Voltage-Positioned Applications
  • 2V to 28V Battery Input Range
  • Requires a Separate 5V Bias Supply
  • 200kHz/300kHz/550kHz/1000kHz Switching Frequency
  • Overvoltage/Undervoltage Protection
  • Drives Large Synchronous-Rectifier FETs
  • 700µA (typ) ICC Supply Current
  • 2µA (typ) Shutdown Supply Current
  • 2V ±1% Reference Output
  • VGATE Blanking During Transition
  • Small 28-Pin QSOP Package

Applications/Uses

  • 2-Cell to 4-Cell Li+ Battery to CPU Core Supply Converters
  • 5V to CPU Core Supply Converters

Description

The MAX1718T step-down controller is intended for core CPU DC-to-DC converters in notebook computers. It features a dynamically adjustable output, ultra-fast transient response, high-DC accuracy, and high efficiency needed for leading-edge CPU core power supplies. Maxim's proprietary Quick-PWM™ quick-response, constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns "instant-on" response to load transients while maintaining a relatively constant switching frequency.

The output voltage can be dynamically adjusted through the 5-bit digital-to-analog converter (DAC) over a 0.6V to 1.75V range. The MAX1718T has an internal multiplexer that accepts three unique 5-bit VID DAC codes corresponding to performance, battery, and suspend modes. Precision slew-rate control provides "just-in- time" arrival at the new DAC setting, minimizing surge currents to and from the battery.

A pair of complementary offset control inputs allows easy compensation for IR drops in PCB traces or creation of a voltage-positioned power supply. Voltage positioning modifies the load-transient response to reduce output capacitor requirements and total system power dissipation.

Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the 5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size.

The MAX1718T is available in a 28-pin QSOP package.

Simplified Block Diagram

MAX1718T: Functional Diagram MAX1718T: Functional Diagram Zoom icon

Technical Docs

Data Sheet Notebook CPU Step-Down Controller Dec 09, 2008

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.