Features and Benefits

  • Two 700mA Switching Regulators with Internal Power Switches
  • Wide 3.6V to 36V Operating Range
  • Overvoltage Lockout Protects Circuit Through 60V Supply Transients
  • Short-Circuit Robust
  • Low Dropout Voltage: 95% Maximum Duty Cycle
  • Adjustable 300kHz to 2.2MHz Switching Frequency Synchronizable Over the Full Range
  • Uses Small Inductors and Ceramic Capacitors
  • Integrated Boost Diodes
  • Internal Compensation
  • Thermally Enhanced 14-Lead (4mm × 3mm) DFN and 16 Lead MSOP Packages

Product Details

The LT3509 is a dual, current mode, step-down switching regulator, with internal power switches each capable of providing 700mA output current. This regulator provides a compact and robust solution for multi-rail systems in harsh environments. It incorporates several protection features including overvoltage lockout and cycle-by-cycle current limit. Thermal shutdown provides additional protection. The loop compensation components and the boost diodes are integrated on-chip. Switching frequency is set by a single external resistor. External synchronization is also possible. The high maximum switching frequency allows the use of small inductors and ceramic capacitors for low ripple. Constant frequency operation above the AM band avoids interference with radio reception, making the LT3509 well suited for automotive applications. Each regulator has an independent shutdown and soft-start control pin. When both converters are powered down, the common circuitry enters a low current shutdown state.


  • Automotive Electronics
  • Industrial Controls
  • Wall Transformer Regulation
  • Networking Devices
  • CPU, DSP, or FPGA Power

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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Reference Designs (2)

Product Recommendations

LT3509 Companion Parts

Recommended Related Parts

Recommended Suggested Oscillator

Design Resources

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PCN-PDN Information

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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.