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PDA Hand-Held-Computer Power Controller

System-Engineered Power Supply for Subnotebook Computers and PDAs

Product Details

Key Features

Simplified Block Diagram

Technical Docs

Data Sheet PDA Hand-Held-Computer Power Controller Jul 01, 1994

Support & Training

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Sampling:
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Key Features

  • +3.3V Step-Down Controller
  • Dual PCMCIA 2.0 Compatible VPP Outputs (0V/3.3V/5V/12V)
  • Digitally Adjustable Switching Current Source for Battery Charging
  • 5 High-Side Switch Gate-Driver Outputs
  • SPI Serial Interface
  • 300kHz Switching Frequency
  • Oscillator SYNC Input
  • 2.5V ±1.5% Reference Output
  • 36-Pin SSOP Package

Applications/Uses

  • Communication Systems
  • Handy Terminals
  • PDAs
  • Subnotebook Computers

Description

The MAX781 is a system-engineered power-supply controller for subnotebook computers, PDAs, or similar battery-powered equipment. It provides high-performance, step-down (buck), pulse-width modulated (PWM) control for generating +3.3V and constant-current battery charging. Dual PCMCIA VPP outputs are powered by a regulated flyback winding. Five high-side gate drivers and a buffered analog multiplexer are also included. All functions are controlled by an SPI/Microwire™ compatible four-wire serial interface.

The MAX781 generates +3.3V with high efficiency through synchronous rectification and PWM operation at heavy loads. It uses Idle Mode™ operation at light loads. Only small external components are required because of the device's high switching frequency (300kHz) and advanced current-mode PWM architecture that allows for output capacitance as low as 50µF per ampere of load.

The MAX781 is configured by 32 bits of serial data. These bits select the operating mode, set the switch-mode battery charger current level, select one of eight analog multiplexer channels, and turn on/off the five high-side gate drivers. A status byte read from the serial interface indicates if the battery has been removed, if the DC charging source has been connected, or if there is a fault condition on the +3.3V output. An interrupt output signals the CPU if a status signal changes.

Simplified Block Diagram

MAX781: Typical Application Circuit MAX781: Typical Application Circuit Zoom icon

Technical Docs

Data Sheet PDA Hand-Held-Computer Power Controller Jul 01, 1994

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.