Low-Noise Regulated Inverter with Integrated LDO

The LM27761 low-noise regulated switched-capacitor voltage inverter delivers a very low-noise adjustable output for an input voltage in the range of 2.7V to 5.5V. Four low-cost capacitors are used in the application design to provide up to 250mA of output current. The regulated output for the device is adjustable between −1.5V and −5V. The LM27761 operates at 2MHz (typical) switching frequency to reduce output resistance and voltage ripple. With an operating current of only 370µA (charge-pump power efficiency greater than 80% with most loads) and 7µA typical shutdown current, the LM27761 provides excellent performance when driving power amplifiers, DAC bias rails, and other high-current, low-noise voltage applications.