LTC3772B - Micropower No RSENSE Constant Frequency Step-Down DC/DC Controller

The LTC3772B is a constant frequency current mode step-down DC/DC controller in a low profile 8-lead SOT-23 (ThinSOT) and a 3mm × 2mm DFN package. The No RSENSE architecture eliminates the need for a current sense resistor, improving efficiency and saving board space.

The LTC3772B automatically switches into pulse skipping operation at light loads. It consumes only 200μA of quiescent current under a no-load condition.

The LTC3772B incorporates an undervoltage lockout feature that shuts down the device when the input voltage falls below 2V. To maximize the runtime from a battery source, the external P-channel MOSFET is turned on continuously in dropout (100% duty cycle). High switching frequency of 550kHz allows the use of a small inductor and capacitors. An internal soft-start smoothly ramps the output voltage from zero to its regulation point.

Features

No Current Sense Resistor Required
High Output Currents Easily Achieved
Internal Soft-Start Ramps VOUT
Wide VIN Range: 2.75V to 9.8V
Low Dropout: 100% Duty Cycle
Constant Frequency 550kHz Operation
Low Ripple Pulse Skipping 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
Only 8μA Supply Current in Shutdown
Low Profile 8-Lead SOT-23 (1mm) and (3mm × 2mm) DFN (0.75mm) Packages

Typical Application

Applications

1- or 2-Cell Li-Ion Battery-Powered Applications
Wireless Devices
Portable Computers
Distributed Power Systems

Packaging

Order Information

Part Number	Package	Temp	Price(1-99)	Price (1k)*
LTC3772BEDDB#PBF	3x2 DFN-8	E	$2.73
LTC3772BEDDB#TRMPBF	3x2 DFN-8	E	$2.73	$1.93
LTC3772BEDDB#TRPBF	3x2 DFN-8	E	$2.73	$1.91
LTC3772BETS8#PBF	SOT-23	E	$2.73
LTC3772BETS8#TRMPBF	SOT-23	E	$2.71	$1.93
LTC3772BETS8#TRPBF	SOT-23	E	$2.71	$1.91

Demo Boards

Part Number	Description	Price
DC924A	LTC3772BEDDB Demo Board \| VIN = 2.75V to 8V, VOUT = 1.8V/2.5V/3.3V @ 2A	Contact Factory