High-Efficiency, 10-Pin µMAX, Step-Down Controllers for Notebooks

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Part Details
  • High Operating Frequency (300kHz)
  • No Current-Sense Resistor
  • Accurate Current Limit
  • ±1% Total DC Error over Line and During Continuous Conduction
  • Dual Mode Fixed Output
    • 1.8V/2.5V/adj (MAX1762)
    • 3.3V/5.0V/adj (MAX1791)
  • 0.5V to 5.5V Output Adjust Range
  • 5V to 20V Input Range
  • Automatic Light-Load Pulse Skipping Operation
  • Free-Running On-Demand PWM
  • Foldback Mode™ UVLO
  • PFET/NFET Synchronous Buck
  • 4.65V at 25mA Linear Regulator Output
  • 5µA Shutdown Supply Current
  • 230µA Quiescent Supply Current
  • 10-Pin µMAX Package
Additional Details
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The MAX1762/MAX1791 PWM step-down controllers provide high efficiency, excellent transient response, and high DC output accuracy needed for stepping down, high-voltage batteries to generate low-voltage CPU core, I/O, and chipset RAM supplies in notebook computers and PDAs.

Maxim's proprietary Quick-PWM™ pulse-width modulator is a free-running constant on-time type with input feed-forward. Its high operating frequency (300kHz) allows small external components to be utilized in PC board area-critical applications such as subnotebook computers and smart phones. PWM operation occurs at heavy loads, and automatic switchover to pulse-skipping operation occurs at lighter loads. The external high-side p-channel and low-side n-channel MOSFETs require no bootstrap components. The MAX1762/MAX1791 are simple, easy to compensate, and do not have the noise sensitivity of conventional fixed-frequency current-mode PWMs.

These devices achieve high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by their ability to drive synchronous-rectifier MOSFETs. The MAX1762/MAX1791 come in a 10-pin µMAX® package and offer two fixed voltages (Dual Mode™) for each device, 1.8V/2.5V/adj (MAX1762) and 3.3V/5.0V/adj (MAX1791).


  • 2-Way Pagers
  • Analog Cellular Phones
  • Digital Cellular Phones
  • Digital Still Cameras
  • Notebook Computers

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Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 1


Evaluation Kit for the MAX1791, MAX1762



Evaluation Kit for the MAX1791, MAX1762

Evaluation Kit for the MAX1791, MAX1762

Features and Benefits

  • No Current-Sense Resistor
  • +5V to +20V Input Voltage Range
  • 3.3V or 5V Preset Output Voltage (MAX1791)
  • 1.8V or 2.5V Preset Output Voltage (MAX1762)
  • Adjustable Output Voltage (1.25V to 5.5V, External Divider)
  • 2A Output Current
  • 300kHz Switching Frequency
  • 5µA IC Shutdown Current
  • 10-Pin µMAX® Package
  • Low-Profile Components
  • Surface-Mount Construction
  • Fully Assembled and Tested

Product Detail

The MAX1791 evaluation kit (EV kit) demonstrates a standard 2A application circuit. This DC-DC converter steps down high-voltage batteries and/or AC adapters, generating a precision, low-voltage rail for use as chipset, I/O, and other low-voltage supplies in notebook computers and PDAs.

The MAX1791 EV kit provides a 3.3V output voltage from a +5V to +20V battery input range. It delivers up to 2A output current with greater than 90% efficiency. The EV kit operates at 300kHz switching frequency and has superior line- and load-transient response.

This EV kit is a fully assembled and tested circuit board. It also allows the evaluation of other output voltages in the 1.25V to 5.5V range by changing feedback resistors R1 and R2. This EV kit can also be used to evaluate the MAX1762 (1.8V or 2.5V output voltage).


  • 1.8V/2.5V Logic and I/O Supplies
  • Digital Still Cameras
  • Handy Terminals
  • Notebook Computers
  • PDAs
  • Smartphones
  • Subnotebooks

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