Datasheet LTC3612 (Analog Devices)

LTC3612 3A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter
FeaTures DescripTion
n
3A Output Current
The LTC®3612 is a low quiescent current monolithic syn- n
2.25V to 5.5V Input Voltage Range
chronous buck regulator using a current mode, constant n
Low Output Ripple Burst Mode
®
Operation: IQ = 70µA
frequency architecture. The no-load DC supply current n
±1% Output Voltage Accuracy
in sleep mode is only 70µA while maintaining the output n
Output Voltage Down to 0.6V
voltage (Burst Mode operation) at no load, dropping to n
High Efficiency: Up to 95%
zero current in shutdown. The 2.25V to 5.5V input supply n Low Dropout Operation: 100% Duty Cycle voltage range makes the LTC3612 ideally suited for single n Shutdown Current: ≤1µA Li-Ion as well as fixed low voltage input applications. 100% n Adjustable Switching Frequency: Up to 4MHz duty cycle capability provides low dropout operation, n Optional Active Voltage Positioning (AVP) with extending the operating time in battery-powered systems. Internal Compensation The operating frequency is externally programmable up to n Selectable Pulse-Skipping/Forced Continuous/ 4MHz, allowing the use of small surface mount inductors. Burst Mode Operation with Adjustable Burst Clamp For switching noise-sensitive applications, the LTC3612 n Programmable Soft-Start can be synchronized to an external clock at up to 4MHz. n Inputs for Start-Up Tracking or External Reference n DDR Memory Mode, I Forced continuous mode operation in the LTC3612 reduces OUT = ±1.5A n Available in Thermally Enhanced 20-Pin noise and RF interference. Adjustable compensation allows (3mm × 4mm) QFN and TSSOP Packages the transient response to be optimized over a wide range of loads and output capacitors.
applicaTions
The internal synchronous switch increases efficiency and n Point-of-Load Supplies eliminates the need for an external catch diode, saving n Distributed Power Supplies external components and board space. The LTC3612 is n Portable Computer Systems offered in a leadless 20-pin 3mm × 4mm QFN or a thermally n DDR Memory Termination enhanced 20-pin TSSOP package. n Handheld Devices L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6580258, 5481178, 5994885, 6304066, 6498466, 6611131.
Typical applicaTion Efficiency and Power Loss vs Load Current
100 10 VIN 90 2.5V TO 5.5V 22µF 80 1 ×2 SVIN PVIN POWER LOSS (W) 70 RUN PVIN_DRV TRACK/SS DDR 60 0.1 RT/SYNC 560nH VOUT 50 LTC3612 SW 2.5V PGOOD SGND 47µF 3A 40 0.01 EFFICIENCY (%) ITH PGND 30 MODE VFB 665k 20 0.001 VIN = 5V 3612 TA01a 10 VIN = 3.3V 210k VIN = 2.8V 0 1 10 100 1000 10000 OUTPUT CURRENT (mA) 3612 TA01b 3612fc For more information www.linear.com/LTC3612 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Package Description Typical Application Related Parts