Switched Capacitor Regulated Voltage Inverter

The LTC1261L is a switched-capacitor voltage inverter designed to provide a regulated negative voltage from a single positive supply. The LTC1261L operates from a single 2.7V to 5.25V supply and provides an adjustable output voltage from -1.23V to ±5V. The LTC1261L-4/LTC1261L-4.5 needs a single 4.5V to 5.25V supply and provides a fixed output voltage of -4V to -4.5V respectively. Three external capacitors are required: a 0.1µF flying capacitor and an input and output bypass capacitors. An optional compensation capacitor at ADJ (COMP) can be used to reduce the output voltage ripple.

Each version of the LTC1261L will supply up to 20mA output current with guaranteed output regulation of ±3.5%. The LTC1261L includes an open-drain REG output that pulls low when the output is within 5% of the set value. Quiescent current is typically 650µA when operating and 5µA in shutdown.

The LTC1261L is available in 8-pin MSOP and SO packages.

Applications

* GaAs FET Bias Generators

* Negative Supply Generators

* Battery-Powered Systems

* Single Supply Applications

* Regulated Negative Voltage from a Single Positive Supply

* REG Pin Indicates Output is in Regulation

* Adjustable or Fixed Output Voltages

* Output Regulation: ±3.5%

* Supply Current: 650µA Typ

* Shutdown Mode Drops Supply Current to 5µA

* Up to 20mA Output Current

* Requires Only Three or Four External Capacitors

* Available in MS8 and SO-8 Packages