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3.3V/5V/Adjustable-Output, Step-Up DC-DC Converters

For New Designs, We Recommend Improved Performance Devices, MAX1674/MAX1675/MAX1676

Product Details

The MAX756/MAX757 are CMOS step-up DC-DC switching regulators for small, low input voltage or battery-powered systems. The MAX756 accepts a positive input voltage down to 0.7V and converts it to a higher pin-selectable output voltage of 3.3V or 5V. The MAX757 is an adjustable version that accepts an input voltage down to 0.7V and generates a higher adjustable output voltage in the range from 2.7V to 5.5V. Typical full-load efficiencies for the MAX756/MAX757 are greater than 87%.

The MAX756/MAX757 provide three improvements over previous devices. Physical size is reduced-the high switching frequencies (up to 0.5MHz) made possible by MOSFET power transistors allow for tiny (< 5mm diameter) surface-mount magnetics. Efficiency is improved to 87% (10% better than with low-voltage regulators fabricated in bipolar technology). Supply current is reduced to 60µA by CMOS construction and a unique constant-off-time pulse-frequency modulation control scheme.

Key Features

  • Operates Down to 0.7V Input Supply Voltage
  • 87% Efficiency at 200mA
  • 60µA Quiescent Current
  • 20µA Shutdown Mode with Active Reference and LBI Detector
  • 500kHz Maximum Switching Frequency
  • ±1.5% Reference Tolerance Over Temperature
  • Low-Battery Detector (LBI/LBO)
  • 8-Pin DIP and SO Packages

Applications/Uses

  • 2-Cell and 3-Cell Battery-Operated Equipment
  • 3.3V to 5V Step-Up Conversion
  • Glucose Meters
  • Medical Instrumentation
  • Palmtop Computers
  • Personal Data Communicators/Computers
  • Portable Data-Collection Equipment
Parametric specs for Step-Up Switching Regulators
VIN (V) (min) 0.7
VIN (V) (max) 5.5
VOUT1 (V) (min) 2.7
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 0.3
Switch Type Internal
Output Adjust. Method Resistor
Power Good Signal Yes
Shutdown Mode Supply Current (µA) (typ) 0.02
# DC-DC Outputs 1
Switching Frequency (kHz) 500
Package/Pins PDIP/8
SOIC (N)/8
Budgetary
Price (See Notes)
$2.16 @1k
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Simplified Block Diagram

MAX756, MAX757: Typical Operating Circuit MAX756, MAX757: Typical Operating Circuit Zoom icon

Technical Docs

Design & Development

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Description

The MAX756 evaluation kit (EV kit) is a fully assembled and tested surface-mount printed circuit board. It can also be modified to fit the adjustable-output MAX757. The MAX756/MAX757 are CMOS, step-up, DC-DC switching regulators for small, low input voltage or battery-powered systems. The MAX756 accepts a positive input voltage down to 0.7V and converts it to a higher pin-selectable output voltage of 3.3V or 5V. The MAX757 is an adjustable version that accepts an input voltage down to 0.7V and generates a higher adjustable output voltage in the 2.7V to 5.5V range. Typical full-load efficiencies for the MAX756/MAX757 are greater than 87%.

A movable jumper selects either 3.3V or 5.0V output voltage, and additional pads on the bottom of the board are provided to place resistors for the LBI/LBO low-battery detector and MAX757 output adjustment.

View Details

Features

  • Operates Down to 0.7V Input Supply Voltage
  • 87% Efficiency at 200mA
  • 60µA Quiescent Current
  • 20µA Shutdown Mode with Active Reference and LBI Detector
  • 500kHz Maximum Switching Frequency
  • ±1.5% Reference Tolerance Over Temperature
  • Low-Battery Detector (LBI/LBO)
  • 8-Pin DIP and SO Packages
  • Surface-Mount Construction
  • Fully Assembled and Tested

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Support & Training

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Parameters

Parametric specs for Step-Up Switching Regulators
VIN (V) (min) 0.7
VIN (V) (max) 5.5
VOUT1 (V) (min) 2.7
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 0.3
Switch Type Internal
Output Adjust. Method Resistor
Power Good Signal Yes
Shutdown Mode Supply Current (µA) (typ) 0.02
# DC-DC Outputs 1
Switching Frequency (kHz) 500
Package/Pins PDIP/8
SOIC (N)/8
Budgetary
Price (See Notes)
$2.16 @1k

Key Features

  • Operates Down to 0.7V Input Supply Voltage
  • 87% Efficiency at 200mA
  • 60µA Quiescent Current
  • 20µA Shutdown Mode with Active Reference and LBI Detector
  • 500kHz Maximum Switching Frequency
  • ±1.5% Reference Tolerance Over Temperature
  • Low-Battery Detector (LBI/LBO)
  • 8-Pin DIP and SO Packages

Applications/Uses

  • 2-Cell and 3-Cell Battery-Operated Equipment
  • 3.3V to 5V Step-Up Conversion
  • Glucose Meters
  • Medical Instrumentation
  • Palmtop Computers
  • Personal Data Communicators/Computers
  • Portable Data-Collection Equipment

Description

The MAX756/MAX757 are CMOS step-up DC-DC switching regulators for small, low input voltage or battery-powered systems. The MAX756 accepts a positive input voltage down to 0.7V and converts it to a higher pin-selectable output voltage of 3.3V or 5V. The MAX757 is an adjustable version that accepts an input voltage down to 0.7V and generates a higher adjustable output voltage in the range from 2.7V to 5.5V. Typical full-load efficiencies for the MAX756/MAX757 are greater than 87%.

The MAX756/MAX757 provide three improvements over previous devices. Physical size is reduced-the high switching frequencies (up to 0.5MHz) made possible by MOSFET power transistors allow for tiny (< 5mm diameter) surface-mount magnetics. Efficiency is improved to 87% (10% better than with low-voltage regulators fabricated in bipolar technology). Supply current is reduced to 60µA by CMOS construction and a unique constant-off-time pulse-frequency modulation control scheme.

Simplified Block Diagram

MAX756, MAX757: Typical Operating Circuit MAX756, MAX757: 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