Datasheet LTC3411A (Analog Devices)

LTC3411A 1.25A, 4MHz, Synchronous Step-Down DC/DC Converter
FeaTures DescripTion
n
Uses Tiny Capacitors and Inductor
The LTC®3411A 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: 0.15Ω
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 up n
Selectable Low Ripple (25mVP-P) Burst Mode®
to 4MHz, allowing the use of tiny, low cost capacitors and
Operation: IQ = 40µA
inductors 1mm or less in height. The output voltage is n Stable with Ceramic Capacitors adjustable from 0.8V to 5.5V. Internal synchronous power n Current Mode Operation for Excellent Line switches provide high efficiency. The LTC3411A’s current and Load Transient Response mode architecture and external compensation allow the n Short-Circuit Protected transient response to be optimized over a wide range of n Low Dropout Operation: 100% Duty Cycle loads and output capacitors. n Low Shutdown Current: IQ ≤ 1µA The LTC3411A can be configured for automatic power n Output Voltages from 0.8V to 5V saving Burst Mode operation (I n Q = 40µA) to reduce gate Synchronizable to External Clock charge losses when the load current drops below the level n Supports Pre-Biased Outputs required for continuous operation. For reduced noise and n Small 10-Lead 3mm × 3mm DFN or MSOP Package RF interference, the SYNC/MODE pin can be configured to
applicaTions
skip pulses or provide forced continuous operation. To further maximize battery life, the P-channel MOSFET n Notebook Computers is turned on continuously in dropout (100% duty cycle). n Digital Cameras In shutdown, the device draws <1µA. n Cellular Phones L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode and OPTI-LOOP are n Handheld Instruments registered trademarks and Hot Swap and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. n Board Mounted Power Supplies Patents including 5481178, 6580258, 6498466, 6611131.
Typical applicaTion Step-Down 2.5V/1.25A Regulator Efficiency and Power Loss vs Output Current
100 1 VIN 2.5V TO 5.5V 90 80 10µF 0.1 70 POWER LOSS (W) SYNC SYNC/MODE PVIN 60 PGOOD SVIN 2.2µH VOUT SW 2.5V 50 0.01 LTC3411A 1.25A 22pF 40 EFFICIENCY (%) 30 0.001 ITH 887k 22µF 20 VIN = 2.7V SHDN/RT VFB V 12.1k IN = 3.6V SGND PGND 10 VIN = 4.2V 0 0.0001 680pF 549k 412k 0.1 1 10 100 1000 10000 OUTPUT CURRENT (mA) 3411a TA01a fO = 1MHz 3411A TA01b Burst Mode OPERATION 3411afd For more information www.linear.com/LTC3411A 1 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 Revision History Typical Application Related Parts