Datasheet LTC3568 (Analog Devices)

LTC3568 1.8A, 4MHz, Synchronous Step-Down DC/DC Converter FeaTures DescripTion n
Uses Tiny Capacitors and Inductor
The LTC®3568 is a constant frequency, synchronous n
High Frequency Operation: Up to 4MHz
step- down DC/DC converter. Intended for medium power n
Low RDS(ON) Internal Switches: 0.110
Ω applications, it operates from a 2.5V to 5.5V input voltage n High Efficiency: Up to 96% range and has a user configurable operating frequency n Stable with Ceramic Capacitors up to 4MHz, allowing the use of tiny, low cost capacitors n Current Mode Operation for Excellent Line and inductors 2mm or less in height. The output voltage and Load Transient Response is adjustable from 0.8V to 5V. Internal sychronous 0.11Ω n Short-Circuit Protected power switches with 2.4A peak current ratings provide n Low Dropout Operation: 100% Duty Cycle high efficiency. The LTC3568’s current mode architecture n Low Shutdown Current: IQ ≤ 1µA and external compensation allow the transient response n Low Quiescent Current: 60µA to be optimized over a wide range of loads and output n Output Voltages from 0.8V to 5V capacitors. n Selectable Burst Mode® Operation The LTC3568 can be configured for automatic power sav- n Sychronizable to External Clock ing Burst Mode operation to reduce gate charge losses n Small 3mm × 3mm, 10-Lead DFN Package when the load current drops below the level required for applicaTions continuous operation. For reduced noise and RF interfer- ence, the SYNC/MODE pin can be configured to skip pulses n or provide forced continuous operation. Notebook Computers n Digital Cameras To further maximize battery life, the P-channel MOSFET n Cellular Phones is turned on continuously in dropout (100% duty cycle) n Handheld Instruments with a low quiescent current of 60µA. In shutdown, the n Board Mounted Power Supplies device draws <1µA. L, LT, LTC, LTM, Linear Technology, the Linear logo, OPTI-LOOP and Burst Mode are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6611131. Typical applicaTion
Efficiency vs Load Current
VIN 2.5V TO 5.5V 100 1000 22µF 95 EFFICIENCY V POWER LOSS (mW) IN SYNC/MODE PVIN L1 PGOOD SV 90 100 IN 2µH SW VOUT LTC3568 2.5V/1.8A 85 ITH 887k 22µF + 10µF POWER LOSS SHDN/RT VFB 13k EFFICIENCY (%) 80 10 SGND PGND VIN = 3.3V VOUT = 2.5V 1000pF 324k 412k 75 fO = 1MHz Burst Mode OPERATION NOTE: IN DROPOUT, THE OUTPUT TRACKS 3568 F01 70 1 THE INPUT VOLTAGE 1 10 100 1000 10000 LOAD CURRENT (mA)
Figure 1. Step-Down 1.8A Regulator
3568 TA01 3568fa Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts