Features

• Wide Operating Supply Voltage Range: 2V to 18V
• Boost Pin (Pin 1) for Higher Switching Frequency
• Simple Conversion of 15V to –15V Supply
• Low Output Resistance: 120Ω Maximum
• Power Shutdown to 8μA with SHDN Pin
• Open Circuit Voltage Conversion Efficiency: 99.9% Typical
• Power Conversion Efficiency: 93% Typical
• Easy to Use

Typical Application

Description

The LTC®1144 is a monolithic CMOS switched-capacitor voltage converter. It performs supply voltage conversion from positive to negative from an input range of 2V to 18V, resulting in complementary output voltages of –2V to –18V. Only two noncritical external capacitors are needed for the charge pump and charge reservoir functions.

The converter has an internal oscillator that can be overdriven by an external clock or slowed down when connected to a capacitor. The oscillator runs at a 10kHz frequency when unloaded. A higher frequency outside the audio band can also be obtained if the Boost Pin is tied to V⁺. The SHDN pin reduces supply current to 8μA and can be used to save power when the converter is not in use.

The LTC1144 contains an internal oscillator, divide-by- two, voltage level shifter, and four power MOSFETs. A special logic circuit will prevent the power N-channel switch substrate from turning on.