LTC3643 - 2A Bidirectional Power Backup Supply
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.
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
 | Applications- Backup Capacitor Systems
- Power Failure Backup Systems
- Solid-State Drives
Packaging |
Order Information
| Part Number | Package | Temp | Price(1-99) | Price (1k)* |
|---|
| LTC3643EUDD#PBF | 3x5 QFN-24 | E | $6.36 | $4.45 |
| LTC3643EUDD#TRPBF | 3x5 QFN-24 | E | | $4.51 |
| LTC3643IUDD#PBF | 3x5 QFN-24 | I | $7.14 | $5.00 |
| LTC3643IUDD#TRPBF | 3x5 QFN-24 | I | | $5.06 |
Demo Boards
| Part Number | Description | Price |
|---|
| 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 |
DatasheetReliability DataPress ReleaseCAD Symbol CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprint compatible with Cadence ORCAD® v16.5 or later, Mentor Graphics PADS® v9.5 or later, and Altium 14.2.5 or later. | Related Product |
