LT1121 LT1121CS8 LT1121CS8-3 LT1121CS8-3.3 LT1121CS8-5 - Micropower Low Dropout Regulators with Shutdown

Features and Benefits

• 0.4V Dropout Voltage

• 150mA Output Current

• 30µA Quiescent Current

• No Protection Diodes Needed

• Adjustable Output from 3.75V to 30V

• 3.3V and 5V Fixed Output Voltages

• Controlled Quiescent Current in Dropout

• Shutdown

• 16µA Quiescent Current in Shutdown

• Stable with 0.33µF Output Capacitor

• Reverse Battery Protection

• No Reverse Current with Input Low

• Thermal Limiting

• Available in the 8-Lead SO, 8-Lead PDIP, 3-Lead SOT-23 and 3-Lead TO-92 Packages

Product details

The LT1121/LT1121-3.3/LT1121-5 are micropower low dropout regulators with shutdown. These devices are capable of supplying 150mA of output current with a dropout voltage of 0.4V. Designed for use in battery-powered systems, the low quiescent current, 30µA operating and 16µA in shutdown, makes them an ideal choice. The quiescent current is well-controlled; it does not rise in dropout as it does with many other low dropout PNP regulators.

Other features of the LT1121/LT1121-3.3/LT1121-5 include the ability to operate with very small output capacitors. They are stable with only 0.33µF on the output while most older devices require between 1µF and 100µF for stability. Small ceramic capacitors can be used, enhancing manufacturability. Also the input may be connected to ground or a reverse voltage without reverse current flow from output to input. This makes the LT1121 series ideal for backup power situationswhere the output is held high and the input is at ground or reversed. Under these conditions only 16µA will flow from the output pin to ground.

Applications

• Low Current Regulator

• Regulator for Battery-Powered Systems

• Post Regulator for Switching Supplies