Features and Benefits
- Synchronous Rectification: Up to 96% Efficiency
- True Output Disconnect
- Inrush Current Limiting
- Very Low Quiescent Current: 12µA
- Up to 1.5A Continuous Output Current
- Fixed Frequency Operation Up to 3MHz
- 0.5V to 4.5V Input Range
- 2.4V to 5.25V Adjustable Output Voltage
- Guaranteed 1V Start-Up
- Programmable Current Limit
- Programmable Soft-Start
- Synchronizable Oscillator
- Manual or Automatic Burst Mode® Operation
- Low-Battery Comparator
- <1µA Shutdown Current
- 1.22V Reference Output Voltage
- Small (4mm × 4mm) Thermally Enhanced QFN Package
The LTC3421 is a high efficiency, current mode, fixed frequency, step-up DC/DC converter with true output disconnect and inrush current limiting. The device includes a 0.10Ω N-channel MOSFET switch and a 0.14Ω P-channel synchronous rectifier. This product has the ability to simply program the output voltage, switching frequency, current limit, soft-start, Burst Mode threshold and loop compensation with external passive components.
Quiescent current is only 12µA during Burst Mode operation, maximizing battery life in portable applications. The oscillator frequency can be programmed up to 3MHz and can be synchronized to an external clock applied to the SYNC pin. An open-drain uncommitted low-battery comparator is included. The part maintains operation in applications with a secondary cell powering the output voltage during shutdown.
Other features include: 1µA shutdown, anti-ringing control, thermal limit and reference output.
The LTC3421 is available in a small 4mm × 4mm QFN package.
- Handheld Computers
- Cordless Phones
- GPS Receivers
- Battery Backup Supplies
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 565 is a constant-frequency synchronous boost converter using the LTC3421. Guaranteed to start-up at 1V input voltage, this converter provides up to 95% efficiency. For 1.8V minimum input voltage, this converter can provide up to 1A load current. This converter has true output disconnect by eliminating body diode conduction of the internal PMOS rectifier. The output voltage is set at 3.3V. A different output voltage in the range of 2.4V to 5.25V can be obtained by changing one of the feedback resistors.
Documentation & Resources
R415 Reliability Data3/23/2018
DC565A - Demo Manual9/24/2009
LTC3421 Dice Specification12/7/2005
Synchronous Boost Converter with Output Disconnect Delivers 4W from Two Cells5/1/2004 LT Journal
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:
LTC3421 Companion Parts
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|
|LTC3421EUF#PBF||Material Declaration||Reliability Data||24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)|
|LTC3421EUF#TRPBF||Material Declaration||Reliability Data||24-Lead QFN (4mm x 4mm x 0.75mm w/ EP)|
|Wafer Fabrication Data||R415 Reliability Data|
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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.