12V/15V or Adjustable, High-Efficiency, Low-I, Step-Up DC-DC Converters

The MAX761/MAX762 step-up switching regulators provide high efficiency over a wide range of load currents, delivering up to 150mA. A unique, current-limited pulse-frequency-modulated (PFM) control scheme gives the devices the benefits of pulse-width-modulated (PWM) converters (high efficiency with heavy loads), while using less than 110µA of supply current (vs. 2mA to 10mA for PWM converters). The result is high efficiency over a wide range of loads.

The MAX761/MAX762 input voltage range is 2V to 16.5V. Output voltages are preset to 12V (MAX761) and 15V (MAX762), or they can be set with two external resistors. With a 5V input, the MAX761 guarantees a 12V, 150mA output. Its high efficiency, low supply current, fast start-up time, SHDN controlling capability, and small size make the MAX761 ideal for powering flash memory.

The MAX761/MAX762 have an internal 1A power MOSFET, making them ideal for minimum-component, low- and medium-power applications. These devices use tiny external components, and their high switching frequencies (up to 300kHz) allow for small surface-mount magnetics.

For increased output drive capability or higher output voltages, use the MAX770-MAX773, which are similar in design to the MAX761/MAX762, but drive external power MOSFETs. For stepping up to 5V, see the MAX756/MAX757 and MAX856-MAX859 data sheets.

Applications

* Battery-Powered Applications * Flash Memory Programming * High-Efficiency DC-DC Converters * PCMCIA Cards

* High Efficiency for a Wide Range of Load Currents

* 12V/150mA Flash Memory Programming Supply

* 110µA Max Supply Current

* 5µA Max Shutdown Supply Current

* 2V to 16.5V Input Voltage Range

* 12V (MAX761), 15V (MAX762) or Adjustable Output

* Current-Limited PFM Control Scheme

* 300kHz Switching Frequency

* Internal, 1A, N-Channel Power FET

* LBI/LBO Low-Battery Comparator