Features

• 3-Phase Controller with Onboard MOSFET Drivers
• Programmable Active Voltage Positioning (AVP) with True Current Sensing
• Programmable External Thermal Detection or Internal Thermal Sensing
• Precise Output Current Matching Optimizes Thermal Performance and Solution Size
• Supports Starting into Precharged V_OUTS
• Differential Amplifier Accurately Senses V_OUT
• PWM, Pulse Skip and Stage SheddingTM Operation
• Synchronizable
• 210kHz to 530kHz Per Phase, Fixed Frequency
• Output Power Good Indicator with Adaptive Blanking
• Adjustable Soft-Start Current Ramping
• Short-Circuit Shutdown Timer with Defeat Option
• OPTI-LOOP® Compensation Minimizes C_OUT
• 38-Lead (5mm × 7mm) QFN Package

Typical Application

Description

The LTC3738 is a 3-phase 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 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 Pulse Skip mode technology.

The LTC3738 also allows users to program load slope via a resistor for AVP control. Both external and internal thermal sensing are available from the on-chip thermal detector and comparator.

A differential amplifier provides sensing of both the high and low sides of the output voltage.

Soft-start and a defeatable, timed short-circuit shutdown protect the MOSFETs and the load. A foldback current circuit also provides protection for the external MOSFETs under short-circuit or overload conditions. An all- “1” VID detector turns off the regulator after a 1µs timeout.

U.S. Patent Numbers: 5481178, 5994885, 5929620, 6177787, 6144194, 6580258, 6462525, 6593724, 6674274, 6100678 pending on AVP technique.