LTC3643 - 2A Bidirectional Power Backup Supply
Features
- Bidirectional Synchronous Boost Capacitor Charger/Buck Regulator for System Backup
- Wide Input Voltage Range: 3V to 17V
- Up to 40V Capacitor Voltage Storage for High Energy Backup
- 2A Maximum CAP Charge Current
- Integrated Power N-Channel MOSFETs (150mΩ Top and 75mΩ Bottom)
- Integrated Power N-Channel MOSFET for Output/CAP Disconnect (50mΩ)
- Input Current Limit During Charging
- Fast 1MHz Switching Frequency
- ±1% Reference Accuracy for System Voltage Regulation
- Indicator Outputs for Charge Status and Input Power Fail
- Low Profile 24-lead 3mm × 5mm QFN Package
Typical Application
Description
The LTC®3643 is a bidirectional synchronous step-up charger and step-down converter which efficiently charges a capacitor array up to 40V from an input supply between 3V to 17V. When the input supply falls below the programmable power-fail threshold, the step-up charger operates in reverse as a synchronous step-down regulator to power the system rail from the backup capacitor during this power interuption/failure condition.
When charging the backup capacitor, an external low-value sense resistor may be used to maintain an accurate current limit from the input supply or implement PowerPath™ functionality.
The step-down converter operates at a 1MHz switching frequency, allowing small external components to be used. Low quiescent current during regulation maximizes the energy usage from the backup capacitor.
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 |
|---|---|---|---|---|---|
| LTC3643EUDD#PBF | 3x5 QFN-24 | UDD | E | 05-08-1833 | Yes |
| LTC3643EUDD#TRPBF | 3x5 QFN-24 | UDD | E | 05-08-1833 | Yes |
| LTC3643IUDD#PBF | 3x5 QFN-24 | UDD | I | 05-08-1833 | Yes |
| LTC3643IUDD#TRPBF | 3x5 QFN-24 | UDD | I | 05-08-1833 | 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 | |
|---|---|---|---|---|---|---|
| LTC3643EUDD#PBF | 3x5 QFN-24 | E | $6.36 | $4.45 | Yes | |
| LTC3643EUDD#TRPBF | 3x5 QFN-24 | E | $4.51 | Yes | ||
| LTC3643IUDD#PBF | 3x5 QFN-24 | I | $7.14 | $5.00 | Yes | |
| LTC3643IUDD#TRPBF | 3x5 QFN-24 | I | $5.06 | 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 |
|---|---|---|---|
| DC2220A | LTC3643 Demo Board | 2A, Bidirectional 40V Boost Charger/Buck Back-Up Power Regulator, 3V ≤ VIN ≤ 17V (Boost), Vout = 5V @ 2A/3A/4A (Buck) | $200.00 | |
| Buy Now | |||
Applications
- Backup Capacitor Systems
- Power Failure Backup Systems
- Solid-State Drives
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Design Tools
Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:
- LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
- LTpowerCAD - A complete power supply selection, synthesis and design tool
- LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
- PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
- Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
- LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
- And More!
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.
