LT1573CS8-3.3#PBF

Overview

The LT1573CS8-3.3#PBF is a low dropout PNP regulator driver manufactured by Analog Devices Inc., housed in an 8-lead SOIC surface-mount package. It provides a fixed 3.3V output with a typical drive current of 20mA and a maximum of 250mA, supporting external pass transistors for up to 5A load currents. The device operates from a single supply voltage ranging from 2.8V to 10V, featuring a reference voltage of 1.265V and a quiescent current of 1.7mA. It includes latching overload protection, thermal shutdown, and a shutdown pin for system control.

Feature Summary

• Integrated latching overcurrent protection minimizes heat sink requirements during fault conditions
• Fast transient response capability reduces the need for large bulk output capacitance
• Precision internal reference ensures accurate fixed output voltage regulation
• Single-supply operation simplifies power architecture design

Applications

• Microprocessor power supply generation
• High current low dropout regulator circuits
• Portable battery-powered systems requiring efficient voltage conversion

Procurement Notes

Verify the specific suffix #PBF indicates lead-free compliance and RoHS adherence before procurement. Confirm the S8 package designation matches your PCB footprint requirements. Ensure the fixed 3.3V variant aligns with your target rail voltage needs rather than the adjustable version.

Selection Notes

Select this component when designing regulators requiring high current handling via external PNPs. Evaluate the external transistor's gain-bandwidth product to ensure stability. Consider the thermal resistance characteristics of your PCB layout to manage junction temperatures under worst-case dissipation scenarios.

Part Context

This part belongs to the LT1573 family of low dropout regulator drivers designed to interface with discrete power transistors. Unlike integrated LDOs, it offers flexibility in output current capacity by allowing the selection of appropriate external pass elements based on specific application voltage drops and thermal constraints.

Replacement Considerations

LT1573CS8-2.5#PBF

FAQ

How is the overcurrent latch reset?

The latch can be reset by pulling the SHDN pin high, grounding the LATCH pin, or cycling the input power off and back on.

What determines the dropout voltage of the circuit?

The dropout voltage is determined by the VCE saturation voltage of the external PNP transistor when driven by the available base current from the LT1573.