Description

The MAX770-MAX773 step-up switching controllers provide 90% efficiency over a 10mA to 1A load. A unique current-limited pulse-frequency-modulation (PFM) control scheme gives these devices the benefits of pulse-width-modulation (PWM) converters (high efficiency at heavy loads), while using less than 110µA of supply current (vs. 2mA to 10mA for PWM converters).These ICs use tiny external components. Their high switching frequencies (up to 300kHz) allow surface-mount magnetics of 5mm height and 9mm diameter.The MAX770/MAX771/MAX772 accept input voltages from 2V to 16.5V. Output voltages are preset at 5V, (MAX770), 12V (MAX771), and 15V (MAX772); they can also be adjusted using two resistors.The MAX773 accepts inputs from 3V to 16.5V. For a wider input range, it features an internal shunt regulator that allows unlimited higher input voltages. The MAX773's output can be set to 5V, 12V, or 15V, or it can be adjusted with two resistors.The MAX770-MAX773 drive external N-channel MOSFET switches, allowing them to power loads up to 15W. If less power is required, use the MAX756/MAX757 or MAX761/MAX762 step-up switching regulators with on-board MOSFETs.ApplicationsBattery-Powered ApplicationsFlash Memory ProgrammingHigh-Efficiency DC-DC ConvertersPalmtops, Handy TerminalsPortable CommunicatorsPositive LCD-Bias Generators