The LTC4040IUFD#PBF is a battery backup power manager for 3.5V to 5.5V supply rail in 24 pin QFN package. This device contains a high current step up DC to DC regulator to backup supply from single cell Li-Ion or LiFePO4 battery. When external power is available, the step up regulator operates in reverse as a step down battery charger. The adjustable input current limit function of LTC4040 reduces charge current to protect main supply from overload while an external disconnect switch isolates the external supply during backup. When input supply drops below the adjustable PFI threshold, the 2.5A boost regulator delivers power from battery to system output. An optional input overvoltage protection (OVP) circuit protects the LTC4040 from high voltage (greater than 60V) damage at VIN pin. One logic input selects either the Li-Ion or LiFePO4 battery option and two other logic inputs program battery charge voltage to one of four levels suitable for backup applications.
Battery voltage range (backup boost input) from 2.7V to 5V
Step up backup supply and step down battery charger
6.5A switches for 2.5A backup from 3.2V battery
Input current limit prioritizes load over charge current
Automatic seamless switch-over to backup mode
Input power loss indicator and system power loss indicator
Pin selectable battery, Li-Ion (3.95V/4.0V/4.05V/4.1V) or LiFePO4 (3.45V/3.5V/3.55V/3.6V)
Constant frequency operation
Operating junction temperature range from -40°C to 125°C
