Top

High-Efficiency, Quad Output, Main Power-Supply Controllers for Notebook Computers

Product Details

Key Features

Simplified Block Diagram

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 .

Key Features

  • No Current-Sense Resistor Needed (MAX1999)
  • Accurate Current Sense with Current-Sense Resistor (MAX1777/MAX1977)
  • 1.5% Output Voltage Accuracy
  • 3.3V and 5V 100mA Bootstrapped Linear Regulators
  • Internal Soft-Start and Soft-Stop Output Discharge
  • Quick-PWM with 100ns Load Step Response
  • 3.3V and 5V Fixed or Adjustable Outputs (Dual Mode™)
  • 4.5V to 24V Input Voltage Range
  • Ultrasonic Pulse-Skipping Mode (25kHz min)
  • Power-Good (PGOOD) Signal
  • Overvoltage Protection Enable/Disable
  • Applications/Uses

    • 3- and 4-Cell Li+ Battery-Powered Devices
    • Notebook and Subnotebook Computers
    • PDAs and Mobile Communication Devices

    Description

    The MAX1777/MAX1977/MAX1999 dual step-down, switch-mode power-supply (SMPS) controllers generate logic-supply voltages in battery-powered systems. The MAX1777/MAX1977/MAX1999 include two pulse-width modulation (PWM) controllers, adjustable from 2V to 5.5V or fixed at 5V and 3.3V. These devices feature two linear regulators providing 5V and 3.3V always-on outputs. Each linear regulator provides up to 100mA output current with automatic linear regulator bootstrapping to the main SMPS outputs. The MAX1777/MAX1977/MAX1999 include on-board power-up sequencing, a power-good (PGOOD) output, digital soft-start, and internal soft-stop output discharge that prevents negative voltages on shutdown.

    Maxim's proprietary Quick-PWM™ quick-response, constant on-time PWM control scheme operates without sense resistors and provides 100ns response to load transients while maintaining a relatively constant switching frequency. The unique ultrasonic pulse-skipping mode maintains the switching frequency above 25kHz, which eliminates noise in audio applications. Other features include pulse skipping, which maximizes efficiency in light-load applications, and fixed-frequency PWM mode, which reduces RF interference in sensitive applications.

    The MAX1777 features a 200kHz/5V and 300kHz/3.3V SMPS for highest efficiency, while the MAX1977 features a 400kHz/5V and 500kHz/3.3V SMPS for “thin and light” applications. The MAX1999 provides a pin-selectable switching frequency, allowing either 200kHz/300kHz or 400kHz/500kHz operation of the 5V/3.3V SMPSs, respectively. The MAX1777/MAX1977/MAX1999 are available in 28-pin QSOP packages and operate over the extended temperature range (-40°C to +85°C). The MAX1777/ MAX1977/MAX1999 are available in lead-free packages.

    Simplified Block Diagram

    MAX1777, MAX1977, MAX1999: Functional Diagram MAX1777, MAX1977, MAX1999: Functional Diagram 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 .