Features

• Regulated Negative Voltage from a Single Positive Supply
• Can Provide Regulated -5V from a 3V Supply
• REG Pin Indicates Output is in Regulation
• Low Output Ripple: 5mV Typ
• Supply Current: 600µA Typ
• Shutdown Mode Drops Supply Current to 5µA
• Up to 15mA Output Current
• Adjustable or Fixed Output Voltages
• Requires Only Three or Four External Capacitors
• Available in SO-8 Packages

Typical Application

Description

The LTC1261 is a switched-capacitor voltage inverter designed to provide a regulated negative voltage from a single positive supply. The LTC1261CS operates from a single 3V to 8V supply and provides an adjustable output voltage from –1.25V to –8V. An on-chip resistor string allows the LTC1261CS to be configured for output voltages of –3.5V, –4V, –4.5V or –5V with no external components. The LTC1261CS8 is optimized for applications which use a 5V or higher supply or which require low output voltages. It requires a single external 0.1µF capacitor and provides adjustable and fixed output voltage options in 8-pin SO packages. The LTC1261CS requires one or two external 0.1µF capacitors, depending on input voltage. Both versions require additional external 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 LTC1261 will supply up to 12mA output current with guaranteed output regulation of 5%. The LTC1261 includes an open-drain REG output which pulls low when the output is within 5% of the set value. Output ripple is typically as low as 5mV. Quiescent current is typically 600µA when operating and 5µA in shutdown. The LTC1261 is available in a 14-pin narrow body SO package and an 8-pin SO package.