特点
High Efficiency: Up to 95%
Constant Frequency 550kHz Operation
V
IN
from 2.65V to 8.5V
V
OUT
from 0.8V to V
IN
OPTI-LOOP? Compensation Minimizes C
OUT
Synchronizable up to 750kHz
Selectable Burst Mode Operation
Low Quiescent Current: 80μA
Low Dropout Operation: 100% Duty Cycle
Secondary Winding Regulation
Soft-Start
Current Mode Operation for Excellent Line and Load Transient Response
Low Quiescent Current: 80μA
Low Shutdown I
Q
= 10μA
±1.5% Reference Accuracy
Precision 2.5V Undervoltage Lockout
Available in 10-Lead MSOP
典型应用
典型应用
描述
The LTC?1773 is a current mode synchronous buck regulator controller that drives external complementary power MOSFETs using a fixed frequency architecture. The operating supply range is from 2.65V to 8.5V, making it suitable for 1- or 2-cell lithium-ion battery powered applications. Burst Mode? operation provides high efficiency at low load currents. 100% duty cycle provides low dropout operation which extends operating time in battery-operated systems.
The operating frequency is internally set at 550kHz, allowing the use of small surface mount inductors. For switching-noise sensitive applications, it can be synchronized up to 750kHz. Peak current limit is user programmable with an external high side sense resistor. A SYNC/FCB control pin guarantees regulation of secondary windings regardless of load on the main output by forcing continuous operation. Burst Mode operation is inhibited during synchronization or when the SYNC/FCB pin is pulled low to reduce noise and RF interference. Soft-start is provided by an external capacitor.
Synchronous rectification increases efficiency and eliminates the need for a Schottky diode, saving components and board space. The LTC1773 comes in a 10-lead MSOP package.