LT1123CST#PBF

Voltage Regulators - Linear Regulator Controllers Overview

The LT1123CST#PBF is a low dropout regulator driver designed for use with discrete PNP power transistors to create cost-effective regulators. It features a fixed 5V output trimmed to ±1% and operates with a quiescent current of 700µA. The device provides line regulation of 1mV and load regulation of 5mV. It includes thermal limiting and guarantees up to 4A output current capability when paired with the specified MJE1123 pass transistor.

Voltage Regulators - Linear Regulator Controllers Feature Summary

• Incorporates a trimmed bandgap reference, error amplifier, and driver circuit capable of sinking up to 125mA from the base of an external PNP pass transistor.
• Features internal thermal limiting and drive current foldback as the feedback pin approaches ground to limit available drive under short-circuit conditions.
• Drive pin can pull down to 2V at 125mA, allowing the use of a series resistor to reduce base drive and minimize power dissipation in the driver.

Voltage Regulators - Linear Regulator Controllers Applications

• Low dropout regulator circuits using discrete PNP power transistors
• Battery backup systems requiring stable 5V output
• Lead acid battery charging applications

Voltage Regulators - Linear Regulator Controllers Procurement Notes

Verify that the ordering suffix #PBF indicates lead-free compliance and RoHS adherence. Confirm the package type matches the design requirements, as this specific part number corresponds to the SOT-223 (ST) package variant rather than the TO-92 plastic package. Ensure the external PNP transistor selected aligns with the drive characteristics required for the target output current.

Voltage Regulators - Linear Regulator Controllers Selection Notes

Select this component when designing a low-cost linear regulator requiring a fixed 5V output. It is intended to be used with an external PNP pass transistor, such as the MJE1123, to handle high output currents. Consider the thermal resistance of the chosen package and the necessity of heat sinking for the pass transistor to ensure operation within maximum junction temperature limits.

Voltage Regulators - Linear Regulator Controllers Part Context

The LT1123 is a specialized driver IC manufactured by Analog Devices Inc. It belongs to a family of low dropout regulator drivers designed to simplify the creation of high-current linear power supplies. The device integrates essential control functions into a compact three-pin configuration, reducing the component count compared to standard regulator designs.

Voltage Regulators - Linear Regulator Controllers Replacement Considerations

LT1123CZ