LM2773 Datasheet, PDF (1/12 Pages) National Semiconductor (TI) – Low-Ripple 1.8V/1.6V Spread-Spectrum Switched Capacitor Step-Down Regulator

January 22, 2008
LM2773
Low-Ripple 1.8V/1.6V Spread-Spectrum Switched
Capacitor Step-Down Regulator
General Description
The LM2773 is a switched capacitor step-down regulator that
produces a selectable 1.8V or 1.6V output. It is capable of
supplying loads up to 300mA. The LM2773 operates with an
input voltage from 2.5V to 5.5V, accommodating 1-cell Li-Ion
batteries and chargers.
The LM2773 utilizes a regulated charge pump with gains of
2/3x and 1x. It has very low ripple and noise on both the input
and output due to its pre-regulated 1.15MHz (typ.) switching
frequency and spread spectrum operation. When output cur-
rents are low, the LM2773 automatically switches to a low-
ripple PFM regulation mode to maintain high efficiency over
the entire load range.
The LM2773 is available in National’s 0.5mm pitch 9-bump
Micro-SMD (µSMD-9).
Features
■ ^{Low-Noise Spread Spectrum Operation}
■ ^{1.8V/1.6V Selectable Output Voltage}
■ ^{2% Output Voltage Regulation}
■ ^{> 75% Efficiency in 1.8V Mode}
■ ^{Very Low Output Ripple: 10mV @ 300mA}
■ ^{Output Currents up to 300mA}
■ ^{2.5V to 5.5V Input Voltage Range}
■ ^{Shutdown Disconnects Load from V}_IN
■ ^{1.15MHz Switching Frequency}
■ ^{No Inductors…Small Solution Size}
■ ^{Short Circuit and Thermal Protection}
■ ^{0.5mm pitch, µSMD-9 (1.511 × 1.511mm × 0.6mm)}
Applications
■ ^{Power Supply for DSP's, Memory, and Microprocessors}
■ ^{Mobile Phones and Pagers}
■ ^{Digital Cameras, Portable Music Players, and Other}
Portable Electronic Devices
Typical Application Circuit
LM2773 Efficiency vs.
Low-Dropout Linear Regulator (LDO) Efficiency
30047401
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