1 Features

• Inverts and regulates the input supply voltage

• Low output ripple

• Shutdown lowers quiescent current to 7μA (typical)

• Up to 250mA output current

• 2.5Ω inverter output impedance, VIN = 5V

• ±4% regulation at peak load

• 370μA quiescent current

• 2MHz (typical) low-noise fixed-frequency operation

• 35dB (typical) LDO PSRR at 2MHz

with 80mA load current

• 30mV LDO dropout voltage at 100mA,

VOUT = –5V

• Current limit and thermal protection

2 Applications

• Operational amplifier power

• Wireless communication systems

• Cellular-phone power-amplifier biasing

• Interface power supplies

• Handheld instrumentation

• Hi-Fi headphone amplifiers

• Powering data converters

3 Description

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.