LTC3522 - Synchronous 400mA Buck-Boost and 200mA Buck Converters
Features
- 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
Typical Application
Description
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.
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC3522EUD#PBF | 3x3 QFN-16 | UD | E | 05-08-1691 | Yes |
| LTC3522EUD#TRPBF | 3x3 QFN-16 | UD | E | 05-08-1691 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3522EUD#PBF | 3x3 QFN-16 | E | $3.57 | $2.50 | Yes | |
| LTC3522EUD#TRPBF | 3x3 QFN-16 | E | $2.56 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1177A | LTC3522EUD Demo Board | Buck-Boost Plus Buck, 2.4V ≤ VIN ≤ 4.3V, Vout1 = 3.3V @ 300mA, Vout2 = 1.8V @ 200mA | $100.00 | |
| Buy Now | |||
Applications
- Flash-Based MP3 Players
- Medical Instruments
- Digital Cameras
- PDAs, Handheld PCs
- Personal Navigation Devices
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
Models for the following parts are available in LTspice:
LTC3522
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
