LTC3409A

LTC3409A 600mA Low VIN Buck Regulator in 3mm × 3mm DFN FEATURES n 1.6V to 5.5V Input Voltage Range n 0.62V to 5.5V Output Voltage Range n Internal Soft-Start n Selectable 1.7MHz or 2.6MHz Constant Frequency Operation n Internal Oscillator Can Be Synchronized to an External Clock, 1MHz to 3MHz Range n High Efficiency: Up to 95% n 65μA Quiescent Current, Burst Mode® Operation n 600mA Output Current (VIN = 1.8V, VOUT = 1.2V) n 750mA Peak Inductor Current n No Schottky Diode Required n Low Dropout Operation: 100% Duty Cycle n 0.612V Reference Voltage n Stable with Ceramic Capacitors n Shutdown Mode Draws <1μA Supply Current n Current Mode Operation for Excellent Line and Load Transient Response n Overtemperature Protection n Available in a Low Profile (0.75mm) 8-Lead (3mm × 3mm) DFN Package APPLICATIONS n Cellular Phones n Digital Cameras n MP3 Players DESCRIPTION The LTC®3409A is a high efficiency, monolithic synchronous buck regulator using a constant frequency, current mode architecture. The LTC3409A improves upon the LTC3409’s light load regulation in Burst Mode operation. The output voltage is adjusted via an external resistor divider. Fixed switching frequencies of 1.7MHz and 2.6MHz are supported. Alternatively, an internal PLL will synchronize to an external clock in the frequency range of 1MHz to 3MHz. This range of switching frequencies allows the use of small surface mount inductors and capacitors, including ceramics. Supply current during Burst Mode operation is only 65...