1.5V, 1.5MHz, 300mA Synchronous Step-Down Regulators in ThinSOT

The LTC3405A-1.5/LTC3405A-1.8 are high efficiency monolithic synchronous buck regulators using a constant frequency, current mode architecture. Supply current during operation is only 20µA and drops to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3405A-1.5/LTC3405A-1.8 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems.

Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors.

The LTC3405A-1.5/LTC3405A-1.8 are specifically designed to work well with ceramic output capacitors, achieving very low output voltage ripple and a small PCB footprint.

The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. The LTC3405A-1.5/LTC3405A-1.8 are available in a low profile (1mm) ThinSOT package.

For adjustable output voltage, refer to the LTC3405A data sheet.

Protected by U.S. Patents, including 6580258, 5481178.

Vout

Features

LTC3405

Adj.

-

LTC3405A

Adj.

Stable With All Ceramic Caps

LTC3405A-1.375

1.375V

Stable With All Ceramic Caps

LTC3405A-1.5

1.5V

Stable With All Ceramic Caps

LTC3405A-1.8

1.8V

Stable With All Ceramic Caps

Applications

* Cellular Telephones

* Personal Information Appliances

* Wireless and DSL Modems

* Digital Still Cameras

* MP3 Players

* Portable Instruments

* High Efficiency: Up to 93%

* Very Low Quiescent Current: Only 20µA During Operation

* 300mA Output Current at VIN = 3V

* 2.5V to 5.5V Input Voltage Range

* 1.5MHz Constant Frequency Operation

* No Schottky Diode Required

* Low Dropout Operation: 100% Duty Cycle

* Stable with Ceramic Capacitors

* Shutdown Mode Draws <1µA Supply Current

* ±3% Output Voltage Accuracy

* Current Mode Operation for Excellent Line and Load Transient Response

* Overtemperature Protected

* Low Profile (1mm) ThinSOT™ Package