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LTC3729
550kHz, PolyPhase, High Efficiency, Synchronous Step-Down Switching Regulator
Overview
Features and Benefits
- Wide VIN Range: 4V to 36V Operation
- Reduces Required Input Capacitance and Power Supply Induced Noise
- ±1% Output Voltage Accuracy
- Phase-Lockable Fixed Frequency: 250kHz to 550kHz
- True Remote Sensing Differential Amplifier
- PolyPhase™ Extends from Two to Twelve Phases
- Reduces the Size and Value of Inductors
- Current Mode Control Ensures Current Sharing
- 1.1MHz Effective Switching Frequency (2-Phase)
- OPTI-LOOP™ Compensation Reduces COUT
- Power Good Output Voltage Indicator
- Very Low Dropout Operation: 99% Duty Cycle
- Adjustable Soft-Start Current Ramping
- Internal Current Foldback Plus Shutdown Timer
- Overvoltage Soft-Latch Eliminates Nuisance Trips
- Available in 5mm x 5mm QFN and 28-Lead SSOP Package
Product Details
The LTC3729 is a multiple phase, synchronous step-down current mode switching regulator controller that drives N-channel external power MOSFET stages in a phase-lockable fixed frequency architecture. The PolyPhase controller drives its two output stages out of phase at frequencies up to 550kHz to minimize the RMS ripple currents in both input and output capacitors. The output clock signal allows expansion for up to 12 evenly phased controllers for systems requiring 15A to 200A of output current. The multiple phase technique effectively multiplies the fundamental frequency by the number of channels used, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified.
An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required for high current applications.
A RUN/SS pin provides both soft-start and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when the overcurrent latchoff is disabled. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3729 includes a power good output pin that indicates when the output is within ±7.5% of the designed set point.
| Vin Max | Vref | |
| LTC3729 | 36V | 0.8 |
| LTC3729L-6 | 30V | 0.6 |
Applications
- Desktop Computers
- Large Memory Arrays
- DC Power Distribution Systems
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)
Documentation
Reliability Data (1)
Application Notes (1)
User Guides (1)
Tools & Simulations
LTspice
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:
Reference Materials
Technical Articles (2)
Design Resources
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.
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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.