LTC3732

` 3-Phase Current Mode Controller with Onboard MOSFET Drivers
` ±5% Output Current Matching Optimizes Thermal Performance and Size of Inductors and MOSFETs
` 4.5V V<sub>CC</sub> 7V; 4.5V V<sub>IN</sub> 32V
` Differential Amplifier Accurately Senses V_OUT
` 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 Shedding^TM or Burst Mode^® Operation
` OPTI-LOOP<sup>®</sup> Compensation Minimizes C<sub>OUT</sub>
` 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

·  Desktop Computers
·  High Performance Notebook Computers
·  High Output Current DC/DC Power Supplies

Topside Driver Voltages (BOOST_N) ........... 38V to 0.3V
Switch Voltage (SW_N).................................. 32V to 5V
Boosted Driver Voltage (BOOST_N SW_N) ..7V to 0.3V
Peak Output Current <1ms (TGN, BGN) ................... 5A
Supply Voltage (V_CC), PGOOD
Pin Voltage ............................................... 7V to 0.3V
RUN/SS, PLLFLTR, PLLIN, FCB Voltages .. V_CC to 0.3V
I_TH Voltage ............................................. 2.4V to 0.3V
Operating Ambient Temperature Range ..0°C to 70°C
Junction Temperature (Notes 2, 3, 7) ................ 125°C
Storage Temperature Range ............65°C to 150°C
Lead Temperature (Soldering, 10 sec)
SSOP Package .................................................. 300°C
Reflow Peak Body Temperature
QFN Package .................................................... 240°C

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.

A differential amplifier of LTC3732 provides true remote sensing of both the high and low side of the output voltage at load points. 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.