TD6811B _{1.5MHz 1.2A Synchronous Step-Down Regulator Dropout}

_(DATASHEET)

The TD6811B 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 of 1.5V and 1.8V. Supply current during operation is only 20mA and drops to ≤1mA in shutdown. The 2.5V to 5.5V input voltage range makes the TD6811 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems.Automatic Burst Mode operation increases efficiency at light loads, further extending battery life.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 TD6811 is available in a low profile (1mm) TSOT23-5 package.

Features

* High Efficiency: Up to 96%

*High Efficiency at light loads (Vin=5V,Vout=3.3V,Ilod=3mA η>82%)

* Very Low Quiescent Current: Only 20uA During Operation

* 1.2A Output Current

* 2.5V to 5.5V Input Voltage Range

* 1.5MHz Constant Frequency Operation

* No Schottky Diode Required

* Low Dropout Operation: 100% Duty Cycle

* 0.6V Reference Allows Low Output Voltages

* Shutdown Mode Draws ≤1uA Supply Current

* Current Mode Operation for Excellent Line and Load Transient Response

* Overtemperature Protected

* Low Profile (1mm) TSOT23-5 Package

Applications

* Cellular Telephones

* Personal Information Appliances

* Wireless and DSL Modems

* Digital Still Cameras

* MP3 Players

* Portable Instruments

Typical Application Circuit