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.