Features and Benefits
- Dual High Efficiency DC/DC Converters:
- Buck-Boost (VOUT: 2.2V to 5.25V, IOUT: 400mA for VIN > 3V, VOUT = 3.3V)
- Buck (VOUT: 0.6V to VIN, IOUT: 200mA)
- 2.4V to 5.5V Input Voltage Range
- Pin Selectable Burst Mode Operation
- 25µA Total Quiescent Current for Both Converters in Burst Mode Operation
- Independent Power Good Indicator Outputs
- Integrated Soft-Start
- Thermal and Overcurrent Protection
- <1µA Quiescent Current in Shutdown
- Small 0.75mm × 3mm × 3mm QFN Package
The LTC3522 combines a 400mA buck-boost DC/DC converter with a 200mA synchronous buck DC/DC converter in a tiny 3mm × 3mm package. The 1MHz switching frequency minimizes the solution footprint while maintaining high efficiency. Both converters feature internal soft-start and compensation, simplifying the design process.
The buck converter is current mode controlled and utilizes an internal synchronous rectifier for high efficiency. The buck converter supports 100% duty cycle operation to extend battery life. If the PWM pin is held low, the buck converter automatically transitions from Burst Mode operation to PWM mode. With the PWM pin held high, the buck converter remains in low noise, 1MHz PWM mode.
The buck-boost converter provides continuous conduction operation to maximize efficiency and minimize noise. At light loads, the buck-boost converter can be placed in Burst Mode operation to improve efficiency and reduce no-load standby current.
The LTC3522 provides a 1µA shutdown mode, overtemperature shutdown and current limit protection on both converters. The LTC3522 is available in a 16-pin low profile 3mm × 3mm QFN package.
- Flash-Based MP3 Players
- Medical Instruments
- Digital Cameras
- PDAs, Handheld PCs
- Personal Navigation Devices
Product Lifecycle 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)
Demonstration circuit DC1177 is a micropower dual Buck-Boost/Buck synchronous converter based on the LTC3522 monolithic regulator. The DC1177 has an input voltage range of 2.4V to 4.2V and outputs 3.3V @ 300mA and 1.8V @ 200mA.
Tools & Simulations
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:
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.
Sample & Buy
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.