Features

• 1x/2x Multimode Charge Pump Supercapacitor Charger
• Automatic Cell Balancing
• Ideal Diode Main PowerPath™ Controller (V_IN to V_OUT)
• Internal 2A LDO Backup Supply (CPO to V_OUT)
• Automatic Main/Backup Switchover
• Input Voltage Range: 2.5V to 5.5V
• Programmable SCAP Charge Voltage
• Programmable Input Current Limit (315mA Max)
• No Load I_VIN = 55μA (Typical)
• Low Profile, 16-Lead 3mm × 3mm QFN Package

Typical Application

Description

The LTC®3226 is a 2-cell series supercapacitor charger with a backup PowerPath controller. It includes a charge pump supercapacitor charger with programmable output voltage, a low dropout regulator, and a power-fail comparator for switching between normal and backup modes.

The constant input current supercapacitor charger is designed to charge two supercapacitors in series to a resistor-programmable output voltage from a 2.5V to 5.3V input supply. The charger input current limit is programmable by an external resistor at up to 315mA.

The internal backup LDO is powered from the supercapacitors and provides up to 2A peak output current with an adjustable output voltage. When the input supply falls below the power-fail threshold, the LTC3226 automatically enters a backup state in which the supercapacitors power the output through the LDO. The input supply power-fail voltage level is programmed by an external resistor divider.

Low input noise, low quiescent current and a compact footprint make the LTC3226 ideally suited for small, batterypowered applications. Internal current limit and thermal shutdown circuitry allow the device to survive a continuous short-circuit from the PROG or CPO pins to ground.