Texas Instruments LM2575T-ADJ/LF02

Overview

LM2575T-ADJ/LF02 from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator in TO-220 package, featuring adjustable output (1.23V–37V), 52 kHz fixed-frequency operation, and integrated thermal shutdown/current limiting. It replaces linear regulators in mid-power DC/DC conversion for industrial power supplies and embedded systems requiring high efficiency and minimal external components.

For engineers reviewing the LM2575T-ADJ/LF02 datasheet, LM2575T-ADJ/LF02 pinout, LM2575T-ADJ/LF02 application, or LM2575T-ADJ/LF02 equivalent, key selection criteria include its 40V max input voltage, ±4% output voltage tolerance over line/load, 1.23V feedback reference, 50 μA standby current with TTL shutdown, and compatibility with standard off-the-shelf inductors.

Technical Context

The LM2575T-ADJ/LF02 implements a fixed-frequency PWM buck topology with internal 52 kHz oscillator, cycle-by-cycle current limiting, and thermal shutdown. Its feedback loop uses a precision 1.23V reference to regulate output via external resistor divider (R1/R2), enabling programmable output from 1.23V to 37V.

It operates across −40°C to +125°C junction temperature, supports up to 40V input, delivers 1A continuous output, and achieves up to 88% efficiency at 12V→5V conversion. Standby mode reduces quiescent current to 50 μA when the ON/OFF pin is pulled high.

Key Specifications

Pinout & Package

LM2575T-ADJ/LF02 is housed in a 5-lead TO-220 package (Package Number NDH0005D) with exposed tab electrically connected to Pin 2 (Output). The package provides θ_JA = 65°C/W (no heatsink) or 45°C/W (with 4 in² copper area), supporting 1A operation at moderate ambient temperatures.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with LM2575HVT-ADJ and LM2596T-ADJ, the LM2575T-ADJ/LF02 provides optimal balance of proven reliability, thermal performance in TO-220, and design simplicity for 1A, ≤40V applications - especially where legacy compatibility and wide temperature support (−40°C to +125°C) are critical.

Availability

LM2575T-ADJ/LF02 is available at Aetrix Electronics and suitable for industrial power supplies, embedded system pre-regulators, on-card DC/DC converters, and positive-to-negative inverter designs requiring stable component supply and long-term manufacturability.

Supply support for LM2575T-ADJ/LF02 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in highly reliable power conversion ICs.

The LM2575 series was designed as a robust, easy-to-use replacement for linear regulators in medium-power buck applications - emphasizing thermal resilience, minimal external parts, and broad industrial temperature operation.

FAQ

What is the maximum input voltage rating for LM2575T-ADJ/LF02?

The LM2575T-ADJ/LF02 has an absolute maximum input voltage of 45V and a recommended operating maximum of 40V. Exceeding 40V risks violating the specified operating conditions and may reduce reliability or trigger overvoltage stress. For 48V or higher input systems, consider the LM2575HVT-ADJ variant rated for 60V operation. Always verify derating margins for your specific thermal and transient conditions when using LM2575T-ADJ/LF02.

How do I set the output voltage of LM2575T-ADJ/LF02?

The LM2575T-ADJ/LF02 output voltage is set using two external resistors (R1 and R2) forming a voltage divider from output to feedback (Pin 4) and ground. Use the formula V_OUT = 1.23V × (1 + R2/R1), with R1 between 1kΩ and 5kΩ. For example, R1 = 2.0kΩ and R2 = 6.12kΩ yields 5.0V. Precision 1% metal film resistors are recommended to maintain regulation accuracy within the ±4% specification of LM2575T-ADJ/LF02.

Does LM2575T-ADJ/LF02 require a heatsink for 1A operation?

LM2575T-ADJ/LF02 can deliver 1A continuously without a heatsink at ambient temperatures ≤50°C when mounted on a PCB with ≥4 in² of copper area around the TO-220 tab (θ_JA = 45°C/W). At higher ambient or with limited copper, thermal calculations show junction temperature may exceed 125°C. For sustained 1A loads above 50°C ambient, a small heatsink or forced airflow is advised. Always validate thermal performance using actual layout and load conditions for your LM2575T-ADJ/LF02 implementation.

What type of catch diode should be used with LM2575T-ADJ/LF02?

A Schottky diode rated for ≥1.2× the peak output current (≥1.2A) and ≥1.25× the maximum input voltage (≥50V for 40V input) is required. Recommended parts include MBR340 (40V, 3A), SR103 (30V, 1A), or 11DQ06 (60V, 1.1A). Fast-recovery diodes like UF4007 may be used if Schottky is unavailable, but efficiency drops ~3–5% due to higher forward voltage. The diode must be placed adjacent to LM2575T-ADJ/LF02 with short, low-inductance traces to minimize ringing and EMI.

Is LM2575T-ADJ/LF02 RoHS compliant and lead-free?

Yes, LM2575T-ADJ/LF02 is RoHS compliant and lead-free, as indicated by the "/LF02" suffix in the part number per Texas Instruments' packaging nomenclature. It meets JEDEC J-STD-020 moisture sensitivity level (MSL) 3 and is compatible with standard lead-free reflow profiles. Full compliance documentation, including substance declarations and test reports, is available through TI's official product folder for LM2575T-ADJ/LF02.