RY3408 5.5V 1A 1.5MHz 同步降压型稳压器.pdf

RY3408 5.5V 1A 1.5MHz Synchronous Step-Down Regulator Features • 2.5V to 5.5V Input Voltage Range • High Efficiency: Up to 96% • 1A Continuous Output Current • Output Adjustable from 0.6V • 1.5MHz Switching Frequency • No Schottky Diode Required • Built-in Short Protection • Over Temperature Protected • Built-in Over Current Limit • Low Quiescent Current: 40μA • Built-in Over Voltage Protection • Available in SOT23-5 package • PFM Mode for High Efficiency in Light Load • -40°C to +85°C Temperature Range • Internal Soft-Start Applications • Cellular and Smart Phones • Portable Instruments • Wireless and DSL Modems • Digital Still and Video Cameras • PDAs • PC Cards General Description The RY3408 is a high-efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. The device is available in an adjustable version. Supply current with no load is 40uA and drops to 1uA in shutdown. The 2.5V to 5.5V input voltage range makes the RY3408 ideally suited for single Li-Ion battery powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. PWM/PFM 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. Low output voltages are easily supported with the 0.6V feedback reference voltage. The RY3408 requires a minimal number of readily available, external components and is available in