AVAILABLE
EVALUATION KIT AVAILABLE
MAX756/MAX757
3.3V/5V/Adjustable-Output, Step-Up DC-DC Converters
_______________Ge...
AVAILABLE
EVALUATION KIT AVAILABLE
MAX756/MAX757
3.3V/5V/Adjustable-Output, Step-Up DC-DC Converters
_______________General 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 pinselectable 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.
________________________Applications
3.3V to 5V Step-Up Conversion
Palmtop Computers
Portable Data-Collection Equipment
Personal Data Communicators/Computers
Medical Instrumentation
2-Cell & 3-Cell Battery-Operated Equipment
Glucose Meters
Functional Diagrams __________Typical Operating Circuit
____________________________Features
♦ Operates Down to 0.7V Input Supply Voltage ♦ 87% Efficiency at 200m...