LT1521CST-3.3#PBF

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The LT1521CST-3.3#PBF is a fixed-output low dropout regulator providing 3.3V at up to 300mA with a maximum dropout voltage of 0.75V. It features micropower quiescent current of 12µA and 6µA in shutdown mode. The device operates within an input voltage range of 4.3V to 20V, includes reverse battery protection, and utilizes a 3-lead SOT-223 package.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Micropower operation with controlled quiescent current that remains stable during dropout conditions
• Integrated shutdown pin for power management reducing standby consumption
• Reverse output protection preventing backflow without external diodes
• Stability with small ceramic output capacitors as low as 1.5µF

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• Battery-powered systems requiring extended operational life
• Backup power circuits where input may be lower than output
• Post-regulation for switching supplies
• Low current linear regulation applications

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify the specific suffix #PBF indicates lead-free compliance and RoHS adherence before procurement. Confirm the ST package designation matches the required SOT-223 footprint for PCB layout. Ensure the fixed 3.3V output variant aligns with system voltage requirements rather than the adjustable version.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this component when a fixed 3.3V rail is needed with minimal quiescent drain. The SOT-223 package suits surface mount designs requiring moderate thermal dissipation. Consider the 0.75V maximum dropout voltage against the minimum available input supply to ensure regulation under all load conditions.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

This part belongs to the LT1521 series of low dropout regulators manufactured by Analog Devices Inc. The series includes adjustable and fixed voltage variants such as 3V and 5V outputs. The CST suffix identifies the specific plastic SOT-223 surface mount package configuration used for this fixed voltage unit.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

LT1521CST-3.3#TRPBF (Tape and Reel version)

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators FAQ

Does the LT1521CST-3.3 require external protection diodes?

No, the device incorporates internal reverse output protection that prevents current flow from the output to the input, eliminating the need for external diodes.

What is the minimum output capacitance required?

The regulator is stable with a minimum output capacitor of 1.5µF, allowing the use of small ceramic capacitors.