LM2577T-ADJ/LB02

Voltage Regulators - DC DC Switching Regulators Overview

The LM2577T-ADJ/LB02 is a SIMPLE SWITCHER step-up voltage regulator from Texas Instruments, designed for high-efficiency power conversion. It operates with an input voltage range of 3.5V to 40V and delivers a switch current of 3A. The output is positive and adjustable, starting at a minimum reference of 1.23V, with the switching element capable of standing off up to 60V. Operating at a fixed frequency of 52kHz, this device supports boost, flyback, and forward converter topologies. It is housed in a TO-220-5 through-hole package with formed leads, suitable for applications requiring robust thermal performance and low component count.

Voltage Regulators - DC DC Switching Regulators Feature Summary

• Integrates current-mode control architecture for improved transient response and simplified compensation requirements.
• Features a built-in free-wheeling diode and internal NPN output switch rated for 3.0A continuous current.
• Includes fixed-frequency oscillator operation to minimize external component count and simplify design.
• Incorporates thermal shutdown circuitry to protect the device during overload or excessive temperature conditions.

Voltage Regulators - DC DC Switching Regulators Applications

• Distributed power supply systems requiring step-up conversion
• Battery-powered devices needing voltage regulation from lower cell voltages
• Negative voltage generation using flyback topology
• Pre-regulators for downstream linear regulators

Voltage Regulators - DC DC Switching Regulators Procurement Notes

Verify the specific suffix LB02 against the manufacturer's latest datasheet to confirm pinout and packaging details, as suffixes can indicate variations in tape-and-reel specifications or regional compliance. Confirm that the TO-220-5 form factor matches your PCB footprint requirements. Check for end-of-life status or obsolescence notices, as older revisions may have limited availability or require qualification for new designs. Ensure the supplier provides original manufacturer documentation to validate authenticity and traceability.

Voltage Regulators - DC DC Switching Regulators Selection Notes

Select this component when a simple, cost-effective step-up solution is needed with an input range up to 40V. It is appropriate for designs where a fixed 52kHz switching frequency is acceptable and thermal management via a TO-220 package is feasible. Consider alternatives if surface-mount technology is required or if higher switching frequencies are necessary to reduce passive component size. Verify that the load current does not exceed the 3A limit under worst-case thermal conditions.

Voltage Regulators - DC DC Switching Regulators Part Context

This part belongs to the LM2577 family of SIMPLE SWITCHER regulators, which are known for their ease of use and minimal external component requirements. The family includes fixed-output variants (e.g., 3.3V, 5V, 12V) and adjustable versions like the ADJ series. The LM2577 series is widely used in industrial and consumer electronics for efficient DC-DC conversion. The TO-220-5 package distinguishes it from smaller SMD packages like TO-263, offering better heat dissipation for higher power applications.

Voltage Regulators - DC DC Switching Regulators Replacement Considerations

The LM2577T-ADJ/LF03 is listed as a parameter-equivalent substitute by Texas Instruments. Verify compatibility regarding the lead-free finish and RoHS compliance status between the LF02 and LF03 suffixes. Ensure that any replacement maintains the same TO-220-5 pinout and electrical characteristics to avoid redesigning the surrounding circuitry.