12V/+15V Step-Up Current-Mode PWM Regulators

The MAX732/M733 are CMOS step-up DC-DC switch-mode regulators. The MAX732 Is a +12V regulator that accepts inputs from 4.0V to 9.3V and delivers up to 200mA of DC current. The MAX733 is a +15V regulator that delivers up to 125mA and accepts inputs from 4.0V to 11.0V. Typical full-load efficiencies are 85% to 92%. They require only a single inductor value of SOμH to function over their entire ranges, so no inductor-related design is necessary. Accuracy is guaranteed over temperature; line, and load variations. The MAX732/ MAX733 use a current-mode pulse-width modulation (PWM) controller to provide precise output regulation and low subharmonic noise. "typical no load supply current is 1.7mA. Fixed 170kHz oscillator frequencies allow easy filterlng of ripple and noise and provide for small external components.

The MAX732/MAX733 feature cycle-by-cycle current limiting, overcurrent limiting, undervoltage lockout, and programmable soft-start protection.

For an adjustable version of these devices, refer to the MAX752 data sheet. For lower-power step-up applications, refer to the MAX632/MAX633 and MAX642/ MAX643 data sheets. For more applications Information, refer to AN-4.1, MAX732 EV Surface-Mount Evaluation Board and Flash EEPROM Power Supply Application Notes.

APPLICATIONS

* Flash Memory Programming Power Supply

* Portable Instruments

* Distributed Power Systems

* Computer Peripherals

* DC-DC Converter Module Replacement

* Load Currents Guaranteed to 200mA with No ExternalM OSFET (125mA tor MAX733)

* 170kHz High-Frequency Current-Mode PWM

* Small Inductor and No Component Design Required

* 85% to 92% Efficiencies at Full Load

* Overcurrent and Soft-Start Protection

* 8-Pln DIP, 18-Pln Wide 80 Packages

* Step-Up from a 4.0V lnput

* Shutdown Pin