Features

• 3-Phase Current Mode Controller with Onboard MOSFET Drivers
• ±5% Output Current Match Optimizes Thermal Performance and Size of Inductors and MOSFETs
• Operational Amplifier Accomodates Mode Switching
• ±1% V_REF Accuracy Over Temperature
• Reduced Input and Output Capacitance
• Reduced Power Supply Induced Noise
• V_OUT Programmable from 0.6V to 1.75V (IMVP III)
• ±10% Power Good Output Indicator
• 250kHz to 600kHz Per Phase, PLL, Fixed Frequency
• PWM, Stage Shedding™ or Burst Mode® Operation
• OPTI-LOOP® Compensation Minimizes C_OUT
• Adjustable Soft-Start Current Ramping
• 4V, V_IN,Undervoltage RUN/SS Reset/Reattempt Circuit
• Short-Circuit Shutdown Timer with Defeat Option
• Overvoltage Soft Latch
• Small 36-Lead Narrow (0.209”) SSOP Package

Typical Application

Description

The LTC3730 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 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 efficiency and ease of thermal design. Light load efficiency is optimized by using a choice of output Stage Shedding or Burst Mode technology.

An internal operational amplifier provides mode selectable output voltage programming in conjunction with the internal VID voltage control DAC.

Soft-start and a defeatable, timed short-circuit shutdown protect the MOSFETs and the load. Current foldback provides protection for the external MOSFETs under short-circuit or overload conditions.