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Rev G – 12/02/2008

SP6669 1.5MHz 0.6A Sync. Step Down Converter © 2008 Exar Corporation

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FEATURES

Up to 600mA Output Current

Up to 95% Efficiency

1.5MHz Constant Frequency Operation

Low Dropout Operation Mode: 100% Duty Cycle

Output Voltages as low as 0.6V

No Schottky Diode Required

200μA Quiescent Current (no load)

Excellent Line and Load Transient Response

Over-Temperature Protection

2.5V to 5.5V Input Voltage Range

Lead Free SOT23-5 Package

APPLICATIONS

Cellular Phones

Wireless Networking

Digital Cameras

Portable Media Players

Bluetooth Devices

Portable Instruments

DESCRIPTION

The SP6669 is a 600mA synchronous buck converter using a constant frequency current

mode architecture with pulse width modulation (PWM) for low output voltage ripple and

fixed frequency noise, a pulse skip mode (PSM) for light load efficiency and a LDO mode for

100% duty cycle. With a 2.5V to 5.5V input voltage range and a 1.5MHz switching

frequency, the SP6669 allows the use of small surface mount inductors and capacitors ideal

for battery powered portable applications. The internal synchronous switch increases

efficiency and eliminates the need for an external Schottky diode. Low output voltages are

easily supported with the 0.6V feedback reference voltage. The SP6669 is available in an

adjustable output voltage version, using an external resistor divider circuit, as well as fixed

output voltage versions of 1.2V, 1.5V and 1.8V. The SP6669 is available in a 5 pin SOT-23

package.

TYPICAL APPLICATION CIRCUIT