LTC3709 - Fast 2-Phase, No RSENSE Synchronous DC/DC Controller with Tracking/Sequencing

Features

  • PolyPhaseTM Valley Current Mode Controller
  • Synchronizable to an External Clock with PLL
  • Coincident or Ratiometric Tracking
  • Sense Resistor Optional
  • 2% to 90% Duty Cycle at 200kHz
  • tON(MIN) < 100ns
  • True Remote Sensing Differential Amplifier
  • High Efficiency at Both Light and Heavy Loads
  • Power Good Output Voltage Monitor
  • 0.6V ±1% Reference
  • Adjustable Current Limit
  • Programmable Soft-Start and Operating Frequency
  • Output Overvoltage Protection
  • Optional Short-Circuit Shutdown Timer
  • 32-Lead (5mm × 5mm) QFN Package

Typical Application

LTC3709 Typical Application
LTC3709 Typical Application

Description

The LTC3709 is a single output, dual phase, synchronous step-down switching regulator. The controller uses a constant on-time, valley current control architecture to deliver very low duty cycles without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in input supply voltage. An internal phase-locked loop allows the LTC3709 to be synchronized to an external clock.

A TRACK pin is provided for tracking or sequencing the output voltage among several LTC3709 chips or an LTC3709 and other DC/DC regulators. Soft-start is accomplished using an external timing capacitor.

Fault protection is provided by an output overvoltage comparator and an optional short-circuit shutdown timer. The current limit level is user programmable. A wide supply range allows voltages as high as 31V to step down to 0.6V.

Protected by U.S. Patents, including 5481178, 6476589, 6144194, 5847554, 6177678, 6304066, 6580258, 6674274, 6462525, 6593724.

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
LTC3709EG#PBF SSOP-24 G E 05-08-1640 (G24) Yes
LTC3709EG#TRPBF SSOP-24 G E 05-08-1640 (G24) Yes
LTC3709EUH#PBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3709EUH#TRPBF 5x5 QFN-32 UH E 05-08-1693 Yes


LTC3709 Package Drawing
LTC3709 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
LTC3709EG#PBF SSOP-24 E $5.83 $4.90 Yes
LTC3709EG#TRPBF SSOP-24 E $5.00 Yes
LTC3709EUH#PBF 5x5 QFN-32 E $5.83 $4.90 Yes
LTC3709EUH#TRPBF 5x5 QFN-32 E $5.00 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
DC793A LTC3709EUH Single Output, Dual Phase Synchronous Buck Converter, 7V to 24Vin, 1.5Vout @ 30A $150.00
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Click here to view our complete list of demo boards

Applications

  • Notebook Computers
  • Power Supply for DSP, ASIC, Graphic Processors

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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:
LTC3709

Technical Support