Linear Technology Corporation announces the LTC3772, a constant frequency current mode step-down DC/DC controller in 2mm x 3mm DFN and low profile 8-lead ThinSOTTM package. The device operates from an input voltage range of 2.75V to 9.8V and can deliver up to 5A of output current to voltages as low as 0.8V, making it ideal for single and dual cell Li-Ion powered applications. Its
No RSENSETM architecture eliminates the need for a current sense resistor, improving efficiency and saving board space.
The LTC3772 automatically switches into Burst Mode operation at light loads to increase efficiency at low output current. It consumes only 40uA of quiescent current under a no-load condition.
The LTC3772 incorporates an undervoltage lockout feature that shuts down the device when the input voltage falls below 2V. To maximize runtime from a battery source, the external P-channel MOSFET is turned on continuously in dropout
(100% duty cycle). A high switching frequency of 550kHz allows the use of a small inductor and capacitors. Additionally an internal soft-start smoothly ramps the output voltage from zero to its regulation point.
The LTC3772EDDB is available from stock in a low profile (0.75mm) 2mm x 3mm DFN-8 package and the LTC3772ETS8 is available in an 8-lead ThinSOT package. Pricing for either device starts at $1.85 each for 1,000 piece quantities.
Summary of Features: LTC3772
•No Current Sense Resistor Required
•40uA No-Load Quiescent Current
•Internal Soft-Start Ramps VOUT
•Wide VIN Range: 2.75V to 9.8V
•Low Dropout: 100% Duty Cycle
•Constant Frequency 550kHz Operation
•Low Ripple Burst Mode Operation at Light Load
•Output Voltage as Low as 0.8V
•1.5% Voltage Reference Accuracy
•Current Mode Operation for Excellent Line and Load Transient Response
•Low Profile (1mm) 8-Lead SOT-23 and (0.75) 2mm x 3mm DFN-8 Package