EVALUATION KIT AVAILABLE MAX756/MAX757 AVAILABLE 3.3V/5V/Adjustable-Output,Step-Up DC-DC Converters_______________General Description____________________________Features The MAX756/MAX757 are CMOS step-up DC-DC switch- ♦ Operates Down to 0.7V Input Supply Voltage ing regulators for small, low input voltage or battery-pow- ered systems. The MAX756 accepts a positive input ♦ 87% Efficiency at 200mA voltage down to 0.7V and converts it to a higher pin- ♦ 60µA Quiescent Current selectable output voltage of 3.3V or 5V. The MAX757 is an adjustable version that accepts an input voltage down ♦ 20µA Shutdown Mode with Active Reference and to 0.7V and generates a higher adjustable output voltage LBI Detector in the range from 2.7V to 5.5V. Typical full-load efficiencies ♦ 500kHz Maximum Switching Frequency for the MAX756/MAX757 are greater than 87%. ♦ ±1.5% Reference Tolerance Over Temperature The MAX756/MAX757 provide three improvements over previous devices. Physical size is reduced—the high ♦ Low-Battery Detector (LBI/LBO) switching frequencies (up to 0.5MHz) made possible by ♦ MOSFET power transistors allow for tiny (<5mm diameter) 8-Pin DIP and SO Packages surface-mount magnetics. Efficiency is improved to 87% (10% better than with low-voltage regulators fabricated in ______________Ordering Information bipolar technology). Supply current is reduced to 60µA by CMOS construction and a unique constant-off-time PARTTEMP. RANGEPIN-PACKAGE pulse-frequency modulation control scheme. MAX756 CPA 0°C to +70°C 8 Plastic DIP MAX756CSA 0°C to +70°C 8 SO ________________________Applications MAX756C/D 0°C to +70°C Dice* 3.3V to 5V Step-Up Conversion MAX756EPA -40°C to +85°C 8 Plastic DIP Palmtop Computers MAX756ESA -40°C to +85°C 8 SO Portable Data-Collection Equipment MAX757 CPA 0°C to +70°C 8 Plastic DIP Personal Data Communicators/Computers MAX757CSA 0°C to +70°C 8 SO Medical Instrumentation MAX757C/D 0°C to +70°C Dice* MAX757EPA -40°C to +85°C 8 Plastic DIP 2-Cell & 3-Cell Battery-Operated Equipment MAX757ESA -40°C to +85°C 8 SO Glucose Meters Functional Diagrams * Dice are tested at TA = +25°C only. __________Typical Operating Circuit_________________Pin ConfigurationsINPUT TOP VIEW 2V to VOUT SHDN 1 8 LX 2 150 3/5 7 GND μF OUTPUT MAX756 3 22μH 6 5 5V at 200mA REF OUT LBI or 4 5 1N5817 LBO LBI 1 8 3.3V at 300mA SHDN LX DIP/SO 100μF MAX756 2 6 3/5 OUT SHDN 1 8 LX 2 FB 7 GND MAX757 3 4 LOW-BATTERY 3 6 REF OUT REF LBO DETECTOR OUTPUT 4 5 LBO LBI Pin Configurations appear at end of data sheet. GND 0.1μF Functional Diagrams continued at end of data sheet. 7 DIP/SO UCSP is a trademark of Maxim Integrated Products, Inc. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com. 19-0113; Rev. 2; 1/95 3.3V/5V/Adjustable-Output,Step-Up DC-DC Converters_______________General Description____________________________Features The MAX756/MAX757 are CMOS step-up DC-DC switch- ♦ Operates Down to 0.7V Input Supply Voltage ing regulators for small, low input voltage or battery-pow- ered systems. The MAX756 accepts a positive input ♦ 87% Efficiency at 200mA voltage down to 0.7V and converts it to a higher pin- ♦ 60µA Quiescent Current selectable output voltage of 3.3V or 5V. The MAX757 is an adjustable version that accepts an input voltage down ♦ 20µA Shutdown Mode with Active Reference and to 0.7V and generates a higher adjustable output voltage LBI Detector in the range from 2.7V to 5.5V. Typical full-load efficiencies ♦ 500kHz Maximum Switching Frequency for the MAX756/MAX757 are greater than 87%. ♦ ±1.5% Reference Tolerance Over Temperature The MAX756/MAX757 provide three improvements over previous devices. Physical size is reduced—the high ♦ Low-Battery Detector (LBI/LBO) switching frequencies (up to 0.5MHz) made possible by ♦ MOSFET power transistors allow for tiny (<5mm diameter) 8-Pin DIP and SO Packages surface-mount magnetics. Efficiency is improved to 87% (10% better than with low-voltage regulators fabricated in ______________Ordering Information 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 * Dice are tested at TA = +25°C only.