LTC3819 - 2-Phase, High Efficiency, Step-Down Controller for Sun Server 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 SUN CPU VID Code:
      VOUT = 1.025V to 1.4125V
  • ±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

LTC3819 Typical Application

Description

The LTC3819 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
LTC3819EG#PBF SSOP-36 G E 05-08-1640 (G36) Yes
LTC3819EG#TRPBF SSOP-36 G E 05-08-1640 (G36) Yes


LTC3819 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
LTC3819EG#PBF SSOP-36 E $5.15 $4.35 Yes
LTC3819EG#TRPBF SSOP-36 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.

Click here to view our complete list of demo boards

Applications

  • Sun™ Server CPU Supply

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

Technical Support