Datasheet LTC3569 (Analog Devices)

LTC3569 Triple Buck Regulator with 1.2A and Two 600mA Outputs and Individual Programmable References
FeaTures DescripTion
n
Three Independent Current Mode Buck DC/DC
The LTC®3569 contains three monolithic, synchronous
Regulators (1.2A and 2
×
600mA)
step-down DC/DC converters. Intended for medium power n
Single Pin Programmable VFB Servo Voltages from
applications, it operates over a 2.5V to 5.5V input voltage
800mV Down to 425mV (in 25mV Steps)
range. The operating frequency is adjustable from 1MHz n
Pull VFB High to Make Each 600mA Buck a Slave for
to 3MHz, allowing the use of tiny, low cost capacitors and
Higher Current Operation
inductors. The three output voltages are independently n
Pulse-Skipping or Burst Mode
®
Operation
programmable by toggling the EN pins up to 15 times, n
Programmable Switching Frequency
lowering the 800mV FB references by 25mV per cycle. The
(1MHz to 3MHz) or Fixed 2.25MHz
first buck regulator sources load currents up to 1200mA. n Synchronizable (1.2MHz to 3MHz) The other two buck regulators each provide 600mA. n VIN Range 2.5V to 5.5V The two 600mA buck regulators can also be configured n All Regulators Internally Compensated to operate as slave power stages, running in parallel with n PGOOD Output Flag another internal buck regulator to supply higher load n Quiescent Current <100µA (All Regulators in Burst currents. When operating as parallel, slave output stages, Mode Operation) discrete external components are shared and available n Zero Shutdown Current output currents sum together. n Overtemperature and Short-Circuit Protection L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n Tiny 3mm × 3mm, 3mm × 4mm 20-Lead QFN 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, 6127815, 6304066, Thermally Enhanced TSSOP FE-16 Packages 6498466, 6580258, 6611131, 7170195.
applicaTions
n Portable Applications with Multiple Supply Rails n General Purpose Step-Down DC/DC n Dynamic Voltage Scaling Applications
Typical applicaTion
VIN 2.2µH* OUT1 = 2.5V SV 22µF IN PVIN SW1
Efficiency vs Load Current
1200mA 20pF 510k 10µF 100 V EN1 FB1 IN = 3V 90 EN2 240k LTC3569 80 EN3 2.5µH** 70 VIN = 5V MODE SW2 OUT2 = 1.8V 600mA 60 RT 20pF 300k 4.7µF FB2 50 PGOOD 240k 40 EFFICIENCY (%) 30 2.5µH** OUT3 = 1.2V SW3 20 600mA Burst Mode OPERATION 20pF 150k 4.7µF 10 PULSE-SKIPPING OUT1 = 2.5V FB3 0 * WURTH 7440430022 0.01 0.1 1 10 100 1000 10000 SGND PGND 300k ** WURTH 744031002 ILOAD (mA) 3569 TA01a 3569 TA01b 3569fe For more information www.linear.com/LTC3569 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 Package Description Revision History Typical Application Related Parts