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本电路可替代AT1366

The AP2408 is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. The device is available in an adjustable version and fixed output voltages, such as 1.2V, 1.8V, etc. Supply current with no load is 300uA and drops to 1uA in shutdown. The 2.5V to 6.5V input voltage range makes the AP2408 ideally suited for single Li-Ion, two to four AA battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive applications. Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors. 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 AP2408 is available in a small SOT package.

lCellular and Smart Phones

lMicroprocessors and DSP Core Supplies

lWireless and DSL Modems

lPDAs

lMP3 / MP4 /MPM Player

lDigital Still and Video Cameras

lPortable Instruments

lHigh Efficiency: Up to 96%

l1.5MHz Constant Switching Frequency

l800mA Output Current at VIN=3.6V

lIntegrated Main switch and synchronous rectifier. No Schottky Diode Required

l2.5V to 6.5V Input Voltage Range

lOutput Voltage as Low as 0.6V

l100% Duty Cycle in Dropout

lQuiescent Current: 300μA(input 4.2V)

lSlope Compensated Current Mode Control for Excellent Line and Load Transient Response

lShort Circuit Protection

lThermal Fault Protection

l1uA Shutdown Current

lSpace Saving 5-Pin SOT23 package