LTC3643 Bidirectional Power Backup Supply

Linear Technology’s bidirectional synchronous step-up charger and step-down converter

Image of Linear Technology LTC3643 Bidirectional Power Backup SupplyThe LTC3643 from Linear Technology efficiently charges a capacitor array up to 40 V from an input supply between 3 V to 17 V. 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 interruption/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 1 MHz switching frequency, allowing small external components to be used. Low quiescent current during regulation maximizes the energy usage from the backup capacitor.

Image of Linear Technology LTC3643 Bidirectional Power Backup Supply Diagram

Features Applications
  • Bidirectional synchronous boost capacitor charger/buck regulator for system backup
  • Wide input voltage range: 3 V to 17 V
  • Up to 40 V capacitor voltage storage for high energy backup
  • 2 A maximum CAP charge current
  • Integrated power N-Channel MOSFETs (150 mΩ top and 75 mΩ bottom)
  • Integrated power N-Channel MOSFET for output/CAP disconnect (50 mΩ)
  • Input current limit during charging
  • Fast 1 MHz switching frequency
  • ±1% reference accuracy for system voltage regulation
  • Indicator outputs for charge status and input power fail
  • Low profile 24-lead 3 mm × 5 mm QFN package
  • Backup capacitor systems
  • Power failure backup systems
  • Solid-state drives

LTC3643 Bidirectional Power Backup Supply

ImageManufacturer Part NumberDescriptionAvailable QuantityView Details
LTC3643EUDD#PBF datasheet linkIC REG BUCK BOOST ADJ 2A SYNCLTC3643EUDD#PBFIC REG BUCK BOOST ADJ 2A SYNC0LTC3643EUDD#PBF product page link
LTC3643IUDD#PBF datasheet linkIC REG BUCK BOOST ADJ 2A SYNCLTC3643IUDD#PBFIC REG BUCK BOOST ADJ 2A SYNC98 - Immediate
1898 - Factory Stock
LTC3643IUDD#PBF product page link

Demonstration Board

ImageManufacturer Part NumberDescriptionAvailable QuantityView Details
DC2220A datasheet linkDEMO BOARD FOR LTC3643DC2220ADEMO BOARD FOR LTC36433 - Immediate
132 - Factory Stock
DC2220A product page link
Published: 2017-11-06