LTC3719 - 2-Phase, High Efficiency, Step-Down Controller for AMD Opteron CPUs

Features

  • Output Stages Operate Antiphase Reducing Input and Output Capacitance Requirements and Power Supply Induced Noise
  • Dual Input Supply Capability for Load Sharing
  • 5-Bit AMD CPU VID Code:
       VOUT = 0.8V to 1.55V
  • ±1% Output Voltage Accuracy
  • True Remote Sensing Differential Amplifier
  • Power Good Output Voltage Monitor
  • Supports Active Voltage Positioning
  • Current Mode Control Ensures Current Sharing
  • OPTI-LOOP® Compensation Minimizes COUT
  • Three Operational Modes: PWM, Burst and Cycle Skip
  • Programmable Fixed Frequency: 150kHz to 300kHz
  • Wide VIN Range: 4V to 36V Operation
  • Adjustable Soft-Start Current Ramping
  • Internal Current Foldback and Short-Circuit Shutdown
  • Overvoltage Soft Latch Eliminates Nuisance Trips
  • Available in 36-Lead Narrow (0.209) SSOP Package

Typical Application

LTC3719 Typical Application

Description

The LTC3719 is a 2-phase, VID programmable, synchronous step-down switching regulator controller that drives two N-channel external power MOSFET stages in a fixed frequency architecture. The 2-phase controller drives its two output stages out of phase at frequencies up to 300kHz to minimize the RMS ripple currents in both input and output capacitors. The 2-phase technique effectively multiplies the fundamental frequency by two, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified.

An operating mode select pin (FCB) can be used to select among three modes including Burst Mode® operation for highest efficiency. An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required in high current applications.

The RUN/SS pin provides 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 for a wide range of output capacitors and ESR values.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LTC3719EG#PBF SSOP-24 G E 05-08-1640 (G24) Yes
LTC3719EG#TRPBF SSOP-24 G E 05-08-1640 (G24) Yes


LTC3719 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC3719EG#PBF SSOP-24 E $5.15 $4.35 Yes
LTC3719EG#TRPBF SSOP-24 E $4.45 Yes
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* 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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC449A-A LTC3719EG | 12Vin, 45Aout 2-Phase VRM, AMD Desktop (Hammer Processor) Contact Factory
DC449A-B LTC3719CG LTC1629-6EG | 12Vin, 45Aout 4-Phase VRM, AMD Server (Hammer Processor) Contact Factory
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Click here to view our complete list of demo boards

Applications

  • Servers and Workstations

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC3719

Technical Support