Overview
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)
- Buck-Boost (VOUT: 2.2V to 5.25V, IOUT = 1A at
- 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.
Applications
- Portable Media Players
- Digital Cameras
- Handheld PCs, PDAs
- GPS Receivers
Product Lifecycle
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)
Documentation
Reliability Data (1)
Evaluation Kit Manuals (1)
Tools & Simulations
LTspice
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

Models for the following parts are available in LTspice:
Reference Materials
Press Releases (1)
Technical Articles (1)
Design Resources
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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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.