LTC4040

LTC4040 2.5A Battery Backup Power Manager Features nn Step-Up Backup Supply and Step-Down Battery Charger nn 6.5A Switches for 2.5A Backup from 3.2V Battery nn Input Current Limit Prioritizes Load Over Charge Current nn Input Disconnect Switch Isolates Input During Backup nn Automatic Seamless Switch-Over to Backup Mode nn Input Power Loss Indicator nn System Power Loss Indicator nn Pin Selectable Battery: Li-Ion (3.95V/4.0V/4.05V/4.1V) or LiFePO4 (3.45V/3.5V/3.55V/3.6V) nn Optional OVP Circuitry Protects Device to >60V nn Constant Frequency Operation nn Low Profile (0.75mm) 24-Lead 4mm × 5mm QFN Package Applications nn Fleet and Asset Tracking nn Automotive GPS Data Loggers nn Automotive Telematics Systems nn Toll Collection Systems nn Security Systems nn USB Powered Devices Description The LTC®4040 is a complete 3.5V to 5.5V supply rail battery backup system. It contains a high current step-up DC/DC regulator to back up the supply from a single-cell Li-Ion or LiFePO4 battery. When external power is available, the step-up regulator operates in reverse as a stepdown battery charger. The LTC4040’s adjustable input current limit function reduces charge current to protect the main supply from overload while an external disconnect switch isolates the external supply during backup. When the input supply drops below the adjustable PFI threshold, the 2.5A boost regulator delivers power from the battery to the system output. An optional input overvoltage protection (OVP) circuit pr...