DESCRIPTION
The LTC®1550L/LTC1551L are switched capacitor charge pump voltage inverters which include internal linear post regulators to minimize output ripple. The LTC1550L fixed output voltage versions include –4.1V, –2.5V and –2V with ripple voltages typically below 1mVP-P. The LTC1550L is also available in an adjustable output voltage version. The LTC1550L/LTC1551L are ideal for use as bias voltage generators for GaAs transmitter FETs in portable RF and cellular telephone applications.

FEATURES
■ Regulated Negative Voltage from a Single Positive Supply
■ Low Output Ripple: Less Than 1mVP-P Typ
■ High Charge Pump Frequency: 900kHz
■ Small Charge Pump Capacitors: 0.1µF
■ Requires Only Four External Capacitors
■ Fixed –4.1V, –2.5V, –2V or Adjustable Output
■ Shutdown Mode Drops Supply Current to <1µA
■ High Output Current: Up to 20mA (Depending on VCC to VOUT Range)
■ Output Regulation: 2.5% Over Line, Load and Temperature
■ Available in 8-Lead MSOP, 8-Lead Narrow SO and 16-Lead Narrow SSOP

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