Texas Instruments LM2575T-5.0/LF03

Overview

LM2575T-5.0/LF03 from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator in TO-220 package, delivering a fixed 5.0V ±4% output across 8–40V input range, with 52 kHz fixed-frequency operation, thermal shutdown, and cycle-by-cycle current limiting. It replaces linear regulators in industrial power supplies requiring high efficiency and minimal external components.

For engineers reviewing the LM2575T-5.0/LF03 datasheet, LM2575T-5.0/LF03 pinout, LM2575T-5.0/LF03 application, or LM2575T-5.0/LF03 equivalent, key selection criteria include its 1A continuous output capability, 77% typical efficiency at 12V_IN/5V_OUT/1A, TO-220 thermal resistance (θ_JA = 65°C/W unheatsinked), and TTL-compatible shutdown with 50 μA standby current.

Technical Context

The LM2575T-5.0/LF03 integrates a PWM controller, power switch, oscillator, error amplifier, and protection circuitry into a single TO-220 device. Its internal 52 kHz oscillator drives a N-channel MOSFET switch with 0.9V saturation voltage at 1A, enabling stable buck conversion without external frequency setting components.

Feedback is internally trimmed to 5.0V for fixed-output variants-no external resistors required-while line regulation holds output within ±0.15V over 8–40V input and load regulation maintains ±0.15V across 0.2–1A load. Protection includes thermal shutdown at 150°C junction temperature and peak current limiting at 2.2A nominal.

Key Specifications

Pinout & Package

LM2575T-5.0/LF03 uses a 5-lead TO-220 package (Package Number NDH0005D) with integrated heatsink tab. Pin 3 is the metal tab (connected to ground), providing low thermal resistance path to PCB copper or external heatsink.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with LM2575T-5.0/LF03, the base LM2575T-5.0 lacks RoHS certification but shares identical performance, while LM2575HVT-5.0 extends input range at no efficiency or thermal penalty-making it a drop-in upgrade only when 48V+ operation is mandatory.

Availability

LM2575T-5.0/LF03 is available at Aetrix Electronics and suitable for industrial power supplies, embedded controller boards, test equipment front-ends, and LED driver bias supplies requiring stable component supply with long lifecycle support.

Supply support for LM2575T-5.0/LF03 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 over 90 years of innovation in high-reliability power solutions.

The LM2575 series was designed as a SIMPLE SWITCHER® solution to replace linear regulators in cost-sensitive, space-constrained industrial and consumer power applications-emphasizing ease of use, minimal external parts, and robust fault protection.

FAQ

What is the maximum input voltage rating for LM2575T-5.0/LF03?

The LM2575T-5.0/LF03 has an absolute maximum input voltage of 45V, with recommended operating range up to 40V DC. This allows reliable operation from 24V industrial buses with headroom for transients. Exceeding 40V risks exceeding thermal limits or triggering overvoltage protection in some conditions, so LM2575HVT-5.0 should be used for 48V systems.

Does LM2575T-5.0/LF03 require external feedback resistors?

No, LM2575T-5.0/LF03 does not require external feedback resistors. As a fixed-output variant, its 5.0V regulation is achieved via internal resistor divider trimming-eliminating component count, layout sensitivity, and drift concerns associated with external networks. Only four external components (inductor, catch diode, input cap, output cap) are needed for full operation.

What thermal performance can be expected from LM2575T-5.0/LF03 without a heatsink?

With no external heatsink and mounted vertically on a PCB with minimum copper area, LM2575T-5.0/LF03 exhibits θ_JA = 65°C/W. At 1A output and 12V input, power dissipation is ~1.7W, resulting in ~110°C junction rise above ambient-requiring ambient <15°C for safe 125°C max junction. Adding ≥4 in² copper area reduces θ_JA to 45°C/W, enabling full 1A operation at 50°C ambient.

Can LM2575T-5.0/LF03 be used in battery-powered applications?

Yes, LM2575T-5.0/LF03 supports battery-powered use via its TTL shutdown pin (Pin 5), which reduces quiescent current to 50 μA typical in standby-extending shelf life significantly. Its 8V minimum input allows operation from two-series LiFePO₄ or three-series alkaline cells with regulation until depletion. Efficiency peaks at 77% (12V→5V), making it suitable for medium-drain portable instruments.

Which catch diode is recommended for LM2575T-5.0/LF03 in a 1A design?

Texas Instruments recommends Schottky diodes such as SR103 or 1N5818 for LM2575T-5.0/LF03 at 1A output. These provide low forward voltage (~0.45V), fast recovery, and adequate 30V reverse rating for 40V input. The diode must handle ≥1.2× load current (1.2A) and withstand ≥1.25× max input voltage (50V), making 30V/1A Schottkys acceptable only if input stays ≤24V; for 36V+ inputs, use MBR340 or equivalent 40V/3A devices.