Power Management Switching Regulator Digitally Programmable Regulators

LTC2974 - 4-Channel PMBus Power System Manager Featuring Accurate Output Current Measurement

LTC3880 - Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management

LTC3738 - 3-Phase Buck Controller for Intel VRM9/VRM10 with Active Voltage Positioning

Features

  • 3-Phase Controller with Onboard MOSFET Drivers
  • Programmable Active Voltage Positioning (AVP) with True Current Sensing
  • Programmable External Thermal Detection or Internal Thermal Sensing
  • Precise Output Current Matching Optimizes Thermal Performance and Solution Size
  • Supports Starting into Precharged VOUTS
  • Differential Amplifier Accurately Senses VOUT
  • PWM, Pulse Skip and Stage SheddingTM Operation
  • Synchronizable
  • 210kHz to 530kHz Per Phase, Fixed Frequency
  • Output Power Good Indicator with Adaptive Blanking
  • Adjustable Soft-Start Current Ramping
  • Short-Circuit Shutdown Timer with Defeat Option
  • OPTI-LOOP® Compensation Minimizes COUT
  • 38-Lead (5mm × 7mm) QFN Package

Typical Application

LTC3738 Typical Application

Description

The LTC3738 is a 3-phase 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 technique effectively triples the fundamental frequency, improving transient response while operating each controller 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 Pulse Skip mode technology.

The LTC3738 also allows users to program load slope via a resistor for AVP control. Both external and internal thermal sensing are available from the on-chip thermal detector and comparator.

A differential amplifier provides sensing of both the high and low sides of the output voltage.

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 a 1µs timeout.

U.S. Patent Numbers: 5481178, 5994885, 5929620, 6177787, 6144194, 6580258, 6462525, 6593724, 6674274, 6100678 pending on AVP technique.

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
LTC3738CUHF#PBF 5x7 QFN-38 UHF C 05-08-1701 Yes
LTC3738CUHF#TRPBF 5x7 QFN-38 UHF C 05-08-1701 Yes


LTC3738 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
LTC3738CUHF#PBF 5x7 QFN-38 C $5.53 $4.65 Yes
LTC3738CUHF#TRPBF 5x7 QFN-38 C $4.75 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
DC721A-A LTC3738CUHF/LTC3731CUH Demo Board | 6-Phase, 8V ≤ VIN ≤ 14V, Vout = VRM9.X / 10.X @ 120A Contact Factory
DC721A-B LTC3738CUHF Demo Board | 3-Phase, 8V ≤ VIN ≤ 14V, Vout = VRM9.X / 10.X @ 65A $190.00
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Click here to view our complete list of demo boards

Applications

  • High Performance Notebook Computers
  • Servers, Desktop Computers and Workstations

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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!

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