1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. External Power Switch Buck Controllers
  6. LTC3709

Alternative Parts


Features and Benefits

  • PolyPhase® 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

Product Details

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.


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

Product Lifecycle icon-recommended 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)

Tools & Simulations


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Product Recommendations

LTC3709 Companion Parts

Recommended Related Parts

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.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
LTC3709EG#PBF Material Declaration Reliability Data 24-Lead SSOP
LTC3709EG#TRPBF Material Declaration Reliability Data 24-Lead SSOP
LTC3709EUH#PBF Material Declaration Reliability Data 32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)
LTC3709EUH#TRPBF Material Declaration Reliability Data 32-Lead QFN (5mm x 5mm x 0.75mm w/ EP)
Wafer Fabrication Data R384 Reliability Data

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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.