DESCRIPTION
The LTC®1429 is a switched-capacitor voltage inverter designed to provide a regulated negative voltage from a single positive supply and permits clock synchronization in noise sensitivesystems.TheLTC1429CSoperatesfromasingle3V to 8V supply and provides an adjustable output voltage from –1.25V to –8V. An on-chip resistor string allows the LTC1429CS to be configured for output voltages of –3.5V, –4V, –4.5V or –5V. The LTC1429CS8 is optimized for applications which require a fixed –4V output from a 5V supply and requires only a single external 0.1mF flying capacitor. The LTC1429CS requires one or two external 0.1mF 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.

FEATURES
■ Regulated Negative Voltage from a Single Positive Supply
■ External Clock for Synchronization in Noise Sensitive Systems
■ REG Output Indicates Output is in Regulation
■ Low Output Ripple: 5mV Typ
■ Can Provide Regulated –5V from a 3V Supply
■ Supply Current: 600mA Typ
■ Shutdown Mode Drops Supply Current to 0.2mA
■ Up to 12mA Output Current
■ Adjustable or Fixed Output Voltages
■ Requires Only Three or Four External Caps
■ Output Regulation: 5%
■ Available in SO-8 Packages

APPLICATIONS
■ GaAs FET Bias Generators
■ Negative Supply Generators
■ Battery Powered Systems
■ Single Supply Applications