MAX38888EVKIT#: Super Capacitor Backup Regulator

The MAX38888 is a storage capacitor or capacitor bank backup regulator designed to efficiently transfer power between a storage element and a system supply rail in reversible buck and boost operations using the same inductor.

When the main supply is present and above the minimum system supply voltage, the regulator operates in buck mode and charges the storage element at up to 500mA peak inductor current. Once the storage element is charged, the circuit draws only 2.5µA of current while it maintains the super capacitor or other storage element in its ready state. When the main supply is removed, the regulator operates in boost mode and prevents the system from dropping below the minimum operating voltage, discharging the storage element at up to 2.5A peak inductor current.

The MAX38888 is externally programmable for minimum and maximum voltage of the storage element, such as super capacitor, minimum system voltage, and maximum charge and discharge currents. The internal DC/DC converter requires only a 1µH inductor.

Benefits and Features

• 2.5V to 5V System Output Voltage

• 0.8V to 4.5V Cap Voltage Range

• Up to 2.5A Peak Inductor Discharge Current

• Programmable Voltage and Current Thresholds

• ±2% Threshold Accuracy

• Up to 95% Efficiency, Charge or Discharge

• 2.5µA Ready Quiescent Current

• 3mm x 3mm x 0.75mm TDFN Package