Features and Benefits
- 3-Phase Controller with Onboard MOSFET Drivers
- Current Mode Control Ensures Current Sharing
- Differential Amplifier Accurately Senses VOUT
- ±5% Output Current Matching Optimizes Thermal Performance and Size of Inductors and MOSFETs
- Reduced Input and Output Capacitance
- Supports Active Voltage Positioning
- VID Programmable Output Voltage from 0.8V to 1.55V (AMD Opteron™ CPU)
- 6-Phase, 90A to 120A Operation
- Output Power Good Indicator with Adaptive Blanking
- 210kHz to 530kHz Per Phase, PLL, Fixed Frequency
- Synchronizable (LTC3733-1)
- PWM, Stage Shedding or Burst Mode® Operation
- OPTI-LOOP® Compensation Minimizes COUT
- Adjustable Soft-Start Current Ramping
- Short-Circuit Shutdown Timer with Defeat Option
- No_CPU Detection
- 36-Lead Narrow SSOP and 38-Lead (5mm × 7mm) QFN
The LTC3733 family are PolyPhase® synchronous stepdown switching regulator controllers that drive 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 530kHz per phase to minimize the RMS current dissipated by the ESR of both the input and output filter capacitors. The 3-phase technique effectively triples the fundamental frequency, improving transient response while operating each phase 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.
A differential amplifier provides true remote sensing of both the high and low sides 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. An all-“1” VID detector turns off the regulator after 1µs timeout.
- High Performance Notebook Computers
- Servers, Desktop Computers and Workstations
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 648 is a high current step-down PolyPhaseTM supply featuring the LTC3733 three-phase synchronous buck controller. It provides high performance power solutions for AMD OpteronTM and AthlonTM 64 processors. The switching frequency range of the LTC3733 is 210kHz to 530kHz. The input supply voltage range is 7V to 21V and the nominal VID programmable output voltage is 0.8V-1.55V. The demo board can supply 65A of output current.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.