MAX1771

AVAILABLE EVALUATION KIT AVAILABLE MAX1771 12V or Adjustable, High-Efficiency, Low IQ, Step-Up DC-DC Controller General Description The MAX1771 step-up switching controller provides 90% efficiency over a 30mA to 2A load. A unique current-limited pulse-frequency-modulation (PFM) control scheme gives this device the benefits of pulse-widthmodulation (PWM) converters (high efficiency at heavy loads), while using less than 110µA of supply current (vs. 2mA to 10mA for PWM converters). This controller uses miniature external components. Its high switching frequency (up to 300kHz) allows surface-mount magnetics of 5mm height and 9mm diameter. It accepts input voltages from 2V to 16.5V. The output voltage is preset at 12V, or can be adjusted using two resistors. The MAX1771 optimizes efficiency at low input voltages and reduces noise by using a single 100mV current-limit threshold under all load conditions. A family of similar devices, the MAX770–MAX773, trades some full-load efficiency f...