Datasheet LTC3565 (Analog Devices)

LTC3565 1.25A, 4MHz, Synchronous Step-Down DC/DC Converter
FEATURES DESCRIPTION
n
High Efficiency: Up to 95%
The LTC®3565 is a constant frequency, synchronous n
VIN Range: 2.5V to 5.5V
step-down DC/DC converter. Intended for medium power n
High Frequency Operation: Up to 4MHz
applications, it operates from a 2.5V to 5.5V input voltage n
Selectable Low Ripple (Typical 25mVp-p)
range and has a user-configurable operating frequency up
Burst Mode® Operation: IQ = 40µA
to 4MHz, allowing the use of tiny, low cost capacitors and n Stable with Ceramic Capacitors inductors 1mm or less in height. The output voltage is n Uses Tiny Capacitors and Inductor adjustable from 0.6V to 5.5V. Internal synchronous power n Low RDS(ON) Internal Switches: 0.15Ω switches provide high efficiency. The LTC3565’s current n Current Mode Operation for Excellent Line mode architecture and external compensation allow the and Load Transient Response transient response to be optimized over a wide range of n Short-Circuit Protected loads and output capacitors. n Low Dropout Operation: 100% Duty Cycle The LTC3565 can be configured for automatic power n Low Shutdown Current: IQ ≤ 1µA saving Burst Mode operation (I n Q = 40µA) to reduce gate Output Voltages from 0.6V to 5V charge losses when the load current drops below the level n Synchronizable to External Clock required for continuous operation. For reduced noise and n Supports Pre-Biased Outputs RF interference, the SYNC/MODE pin can be configured to n Small 10-Lead (3mm × 3mm) DFN or MSOP Package skip pulses or provide forced continuous operation.
APPLICATIONS
To further maximize battery life, the P-channel MOSFET is turned on continuously in dropout (100% duty cycle). n Notebook Computers In shutdown, the device draws <1µA. n Digital Cameras L, LT, LTC, LTM, Linear Technology the Linear logo, Burst Mode and OPTI-LOOP are registered n trademarks of Linear Technology Corporation. Hot Swap and ThinSOT are trademarks of Linear Cellular Phones Technology Corporation. All other trademarks are the property of their respective owners. n Handheld Instruments Protected by U.S. Patents including 5481178, 6580258, 6498466, 6611131. n Board Mounted Power Supplies
TYPICAL APPLICATION Step-Down 2.5V/1.25A Regulator Efficiency and Power Loss vs Output Current
VIN 100 1 2.5V TO 5.5V 90 22µF 80 0.1 70 POWER LOSS (W) SYNC/MODE SVIN PVIN RUN 60 2.2µH VOUT PGOOD SW 2.5V 50 0.01 LTC3565 1.25A ITH 40 22µF EFFICIENCY (%) RT 22pF 30 12.1k 0.001 20 VIN = 2.7V VFB VIN = 3.6V GND 931k 10 VIN = 4.2V 680pF 191k 294k 0 0.0001 0.1 1 10 100 1000 10000 OUTPUT CURRENT (mA) 3565 TA01a 3565 TA01b 3565fc For more information www.linear.com/LTC3565 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 Application Package Description Revision History Typical Application Related Parts