DESCRIPTION
The LTC®3569 contains three monolithic, synchronous step-down DC/DC converters. Intended for medium power applications, it operates over a 2.5V to 5.5V input voltage range. The operating frequency is adjustable from 1MHz to 3MHz, allowing the use of tiny, low cost capacitors and inductors. The three output voltages are independently programmable by toggling the EN pins up to 15 times, lowering the 800mV FB references by 25mV per cycle. The fi rst buck regulator sources load currents up to 1200mA. The other two buck regulators each provide 600mA.

FEATURES
■ Three Independent Current Mode Buck DC/DC
   Regulators (1.2A and 2x 600mA)
■ Single Pin Programmable VFB Servo Voltages from
   800mV Down to 425mV (in 25mV Steps)
■ Pull VFB High to Make Each 600mA Buck a Slave for
   Higher Current Operation
■ Pulse Skip or Burst Mode® Operation
■ Programmable Switching Frequency
   (1MHz to 3MHz) or Fixed 2.25MHz
■ Synchronizable (1.2MHz to 3MHz)
■ VIN Range 2.5V to 5.5V
■ All Regulators Internally Compensated
■ PGOOD Output Flag
■ Quiescent Current <100μA (All Regulators in Burst
   Mode Operation)
■ Zero Shutdown Current
■ Overtemperature and Short-Circuit Protection
■ Tiny 3mm × 3mm 20-Lead QFN and Thermally
   Enhanced TSSOP FE-16 Packages

APPLICATIONS
■ Portable Applications with Multiple Supply Rails
■ General Purpose Step-Down DC/DC
■ Dynamic Voltage Scaling Applications