1. Products
  2. Power Management
  3. Switching Regulators
  4. Buck-Boost Regulators
  5. Internal Power Switch Buck-Boost Regulators
  6. LTC3520


Features and Benefits

  • Dual High Efficiency DC/DC Converters:
    • Buck-Boost (VOUT: 2.2V to 5.25V, IOUT = 1A at
      VOUT = 3.3V, VIN ≥ 3V)
    • Buck (VOUT: 0.8V to VIN, IOUT = 600mA)
  • 2.2V to 5.5V Input Voltage Range
  • Pin-Selectable Burst Mode® Operation
  • Uncommitted Gain Block for LDO Controller, Battery Good Indication or Sequencing
  • Programmable 100kHz to 2MHz Switching Frequency
  • 55μA Total Quiescent Current for Both Converters in Burst Mode Operation
  • Thermal and Overcurrent Protection
  • <1μA Quiescent Current in Shutdown
  • 24-Lead 4mm × 4mm QFN Package

Product Details

The LTC3520 combines 1A buck-boost and 600mA synchronous buck DC/DC converters in a tiny 4mm x 4mm package. A programmable switching frequency allows the efficiency to be optimized while minimizing the solution footprint. Both converters feature soft-start and current limit protection. The uncommitted gain block can be configured as an LDO or utilized as a battery-good comparator.

The buck converter is current mode controlled with internal synchronous rectification to improve efficiency. Pin-selectable Burst Mode operation can be enabled to improve light load efficiency, or the buck converter can be operated in low noise PWM mode for sensitive applications.

The buck-boost converter provides continuous conduction operation to maximize efficiency and minimize noise. At light loads, use of Burst Mode operation will improve efficiency.

The LTC3520 provides a <1µA shutdown mode and over- temperature shutdown on both converters. The LTC3520 is available in a low profile (0.75mm) 24-lead 4mm x 4mm QFN package.


  • Portable Media Players
  • Digital Cameras
  • Handheld PCs, PDAs
  • GPS Receivers

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Evaluation Kits (1)

Tools & Simulations


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Product Recommendations

LTC3520 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
LTC3520EUF#PBF Material Declaration Reliability Data 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)
LTC3520EUF#TRPBF Material Declaration Reliability Data 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)
LTC3520IUF#PBF Material Declaration Reliability Data 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)
LTC3520IUF#TRPBF Material Declaration Reliability Data 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)
Wafer Fabrication Data R457 Reliability Data

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Sample & Buy

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Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.

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.