DESCRIPTION
The LTC®3732 is a PolyPhase® synchronous step-down switching regulator controller that drives all N-channel external power MOSFET stages in a phase-lockable fixed frequency architecture. The 3-phase controller drives its output stages with 120° phase separation at frequencies of up to 600kHz per phase to minimize the RMS current losses in both the input and output filter capacitors. The 3- phase technique effectively triples the fundamental frequency, improving transient response while operating each controller at an optimal frequency for high efficiency and ease of thermal design. Light load efficiency is optimized by using a choice of output Stage Shedding or Burst Mode technology.

FEATURES
■ 3-Phase Current Mode Controller with
   Onboard MOSFET Drivers
■ ±5% Output Current Matching Optimizes Thermal
   Performance and Size of Inductors and MOSFETs
■ 4.5V ≤ VCC ≤ 7V; 4.5V ≤ VIN ≤ 32V
■ Differential Amplifier Accurately Senses VOUT
■ Reduced Input and Output Capacitance
■ Reduced Power Supply Induced Noise
■ VID DAC Programmable from 1.1V to 1.85V
   (VRM9.0/9.1)
■ ±10% Power Good Output Indicator
■ 250kHz to 600kHz Per Phase, PLL, Fixed Frequency
■ PWM, Stage SheddingTM or Burst Mode® Operation
■ OPTI-LOOP® Compensation Minimizes COUT
■ Adjustable Soft-Start Current Ramping
■ Short-Circuit Shutdown Timer with Defeat Option
■ Overvoltage Soft Latch
■ Small 36-Lead Narrow (0.209") SSOP Package
■ QFN 5mm × 7mm 38-Lead Package

APPLICATIONS
■ Desktop Computers
■ High Performance Notebook Computers
■ High Output Current DC/DC Power Supplies