LTC3521
RECOMMENDED FOR NEW DESIGNS1A Buck-Boost DC/DC and Dual 600mA Buck DC/DC Converters
- Part Models
- 8
- 1ku List Price
- Starting From $4.92
Overview
- Three High Efficiency DC/DC Converters:
- Buck-Boost (VOUT: 1.8V to 5.25V, IOUT: 1A)
- Dual Buck (VOUT: 0.6V to VIN, IOUT: 600mA)
- 1.8V to 5.5V Input Voltage Range
- Pin-Selectable Burst Mode® Operation
- 30μA Total Quiescent Current in Burst Mode Operation
- Independent Power Good Indicator Outputs
- Integrated Soft-Start
- Thermal and Overcurrent Protection
- <2μA Current in Shutdown
- Small 4mm × 4mm QFN and Thermally Enhanced TSSOP Packages
The LTC3521 combines a 1A buck-boost DC/DC converter and dual 600mA synchronous buck DC/DC converters. The 1.1MHz switching frequency minimizes the solution footprint while maintaining high efficiency. All three converters feature soft-start and internal compensation to minimize the solution footprint and simplify the design process.
The buck converters are current mode controlled and utilize an internal synchronous rectifier to improve efficiency. The buck converters support 100% duty cycle operation to extend battery life. If the PWM pin is held low, the buck converters automatically transition from Burst Mode operation to PWM mode at high loads. With the PWM pin held high, the buck converters remain in low noise, 1.1MHz PWM mode.
The buck-boost converter features continuous conduction operation to maximize efficiency and minimize noise. At light loads, the buck-boost converter can be operated in Burst Mode operation to improve efficiency and reduce no-load standby current.
The LTC3521 provides a <2μA shutdown mode, overtemperature shutdown and current limit protection on all converters. The LTC3521 is available in a 24-pin 0.75mm × 4mm × 4mm QFN package, and a 20-pin thermally enhanced TSSOP package.
Applications
- Bar Code Readers
- Medical Instruments
- Handy Terminals
- PDAs, Handheld PCs
- GPS Receivers
Documentation
Data Sheet 1
User Guide 1
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 Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| LTC3521EFE#PBF | 20-Lead TSSOP w/ EP | ||
| LTC3521EFE#TRPBF | 20-Lead TSSOP w/ EP | ||
| LTC3521EUF#PBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) | ||
| LTC3521EUF#TRPBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) | ||
| LTC3521IFE#PBF | 20-Lead TSSOP w/ EP | ||
| LTC3521IFE#TRPBF | 20-Lead TSSOP w/ EP | ||
| LTC3521IUF#PBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) | ||
| LTC3521IUF#TRPBF | 24-Lead QFN (4mm x 4mm x 0.75mm w/ EP) |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
May 18, 2026 - 26_0072 Epoxy Change for Select TSSOP Products |
||
| LTC3521EFE#PBF | PRODUCTION | |
| LTC3521EFE#TRPBF | PRODUCTION | |
| LTC3521IFE#PBF | PRODUCTION | |
| LTC3521IFE#TRPBF | PRODUCTION | |
|
Feb 14, 2025 - 25_0017 Bond Wire Change from Gold to Copper |
||
| LTC3521EFE#PBF | PRODUCTION | |
| LTC3521EFE#TRPBF | PRODUCTION | |
| LTC3521IFE#PBF | PRODUCTION | |
| LTC3521IFE#TRPBF | PRODUCTION | |
|
Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL |
||
| LTC3521EFE#PBF | PRODUCTION | |
| LTC3521EFE#TRPBF | PRODUCTION | |
| LTC3521IFE#PBF | PRODUCTION | |
| LTC3521IFE#TRPBF | PRODUCTION | |
|
Apr 14, 2025 - 25_0017 Bond Wire Change from Gold to Copper |
||
| LTC3521EUF#PBF | PRODUCTION | |
| LTC3521EUF#TRPBF | PRODUCTION | |
| LTC3521IUF#PBF | PRODUCTION | |
| LTC3521IUF#TRPBF | PRODUCTION | |
|
Feb 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products |
||
| LTC3521EUF#PBF | PRODUCTION | |
| LTC3521EUF#TRPBF | PRODUCTION | |
| LTC3521IUF#PBF | PRODUCTION | |
| LTC3521IUF#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
Can't find the software or driver you need?
Request a Driver/SoftwareTools & Simulations
LTspice 1
Models for the following parts are available in LTspice:
- LTC3521
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.
Evaluation Kits
LTC3521EUF Demo Board | Buck-Boost Plus Dual Buck, 2.4V ≤ VIN ≤ 5V, VOUT1 = 3.3V @ 0.8A, VOUT2 = 1.2V @ 0.6A, VOUT3 = 1.8V @ 0.6A
Resources
Latest Discussions
No discussions on LTC3521 yet. Have something to say?
Start a Discussion on EngineerZone®