FEATURES
• Optimized for Low Voltage Applications
• 2.6-to-7V Operating Input Range
• 8V Max Input Blocking Voltage
• Adjustable In-rush Current Control
• Configurable Input Power Failure Level
• Programmable up to 6A Input Current Limit
• Programmable 5V to 28V Boost Storage Voltage
• 28V@4A Synchronous Buck Supports 100%
Duty Cycle
• Programmable up to 2.25MHz Buck Operating
Frequency for Small Inductor Size
• Power Loss, Vout Power Good, and Storage Cap
Power Good Indicators
• Compatible with Different Types of Storage Caps:
Super Caps, Electrolytic, Tantalum, POSCAP etc.
• Autonomous Health Monitoring for Detection of
Earlier Storage Capacitor Failures
• Configurable Interrupts to Inform Host for any
Faults/Status Change
• eFuse, Boost, and Buck UV/OV/OC Protection
• Thermal Alert and Protection
• Thermal Enhanced FCQFN 4x4-32 package

APPLICATIONS
• Solid State Drives
• Power Backup Systems
• Industrial Applications
• eFuse
• Hot Plug Devices

GENERAL DESCRIPTION
The ACT4921 device is a highly integrated power loss
protection IC. It provides backup storage power in the
event of an input power failure. A built-in boost converter
provides high voltage energy storage to minimize
storage capacitor size requirements. The built-in buck
converter regulates the storage voltage to a fixed output
voltage. It contains internal, back-to-back eFuse FETs
to provide bi-directional input to output isolation. The IC
also provides hot swap and inrush current control.
The ACT4921 is very flexible and can easily be
configured with I2C and external components. It
features programmable storage capacitor voltage to
optimize the storage capacitor sizing and system run
time. The internal health monitoring provide an extra
layer of protection and improve system reliability and
early capacitor failure notification. It automatically
checks the storage capacitor health and notifies the
user when the energy in the storage caps is not
sufficient for backup power. The built-in synchronous
buck converter maximizes energy transfer from the
storage caps to the system.
ACT4921 provides an I2C bus interface to allow MCU
control and monitoring. There are supervisor monitors
for the input voltage, output voltage, and storage
voltage. It is available with the thermal enhanced QFN
4x4 32 pin package.