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 step-down 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 protects the LTC4040 from high voltage damage at the VIN pin. One logic input selects either the Li-Ion or the LiFePO4 battery option, and two other logic inputs program the battery charge voltage to one of four levels suitable for backup applications. The LTC4040 is available in a low profile (0.75mm) 24-Lead 4mm × 5mm QFN package.
Part Number | Package | Temp | Price(1-99) | Price (1k)* |
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LTC4040EUFD#PBF | 4x5 QFN-24 | E | $4.14 | $2.90 |
LTC4040EUFD#TRPBF | 4x5 QFN-24 | E | $4.20 | $2.96 |
LTC4040IUFD#PBF | 4x5 QFN-24 | I | $4.71 | $3.30 |
LTC4040IUFD#TRPBF | 4x5 QFN-24 | I | $3.36 |
Part Number | Description | Price |
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DC2118A | LTC4040 Demo Board | 5VIN, 2A Single Cell Li-ion/LiFePO4 Buck Battery Charger with 2.5A Boost Backup Power Manager | Contact Factory |