Texas Instruments LM2575T-15/LF03

Overview

LM2575T-15/LF03 from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator in a 5-lead TO-220 package, delivering a fixed 15V output with ±4% tolerance across 0.2–1A load and 18–40V input. It integrates PWM controller, power switch, and thermal/current protection, enabling compact, high-efficiency DC/DC conversion for industrial power supplies and embedded systems.

For engineers reviewing the LM2575T-15/LF03 datasheet, LM2575T-15/LF03 pinout, LM2575T-15/LF03 application, or LM2575T-15/LF03 equivalent, this page delivers verified technical context, exact pin functions, real-world design constraints (e.g., 52 kHz fixed oscillator, 0.9V saturation voltage), and validated alternative parts - all grounded in TI's SNVS106E datasheet and official package documentation.

Technical Context

The LM2575T-15/LF03 implements a current-mode PWM buck topology with internal 52 kHz oscillator, cycle-by-cycle current limiting, and thermal shutdown. Its feedback loop references a precise 1.23V internal bandgap, enabling stable 15V regulation without external compensation components.

It operates over −40°C to +125°C junction temperature, supports TTL-compatible shutdown (ISTBY = 50 μA typ), and requires only four external components: input capacitor, output capacitor, catch diode, and inductor - with standard 330 μH inductors optimized for 15V output at 1A.

Key Specifications

Pinout & Package

LM2575T-15/LF03 uses a 5-lead TO-220 package (Package Number NDH0005D), with the tab electrically connected to Pin 2 (Output). Thermal resistance is θJA = 65°C/W (no heatsink) or 45°C/W (4 in² copper area).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2575HVT-15 and LM2596T-15, LM2575T-15/LF03 delivers optimal balance of proven reliability, thermal manageability in TO-220, and minimal external component count for 1 A, 15 V applications within 40 V input limits - making it ideal for cost-sensitive industrial and embedded designs where layout reuse is critical.

Availability

LM2575T-15/LF03 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-15/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 ICs, with decades of expertise in switching regulator design and manufacturing.

The LM2575 series was engineered as a drop-in, high-efficiency replacement for linear regulators in medium-power industrial and embedded applications - prioritizing simplicity, thermal robustness, and minimal external component count.

FAQ

What is the absolute maximum input voltage rating for LM2575T-15/LF03?

The absolute maximum input voltage for LM2575T-15/LF03 is 45 V, per TI's SNVS106E datasheet Absolute Maximum Ratings table. However, the recommended operating range is 18 V to 40 V. Exceeding 40 V risks violating the specified output voltage accuracy and thermal limits, and sustained operation above 45 V may cause permanent device failure. Always include input transient suppression if used in automotive or industrial environments with voltage spikes.

Can LM2575T-15/LF03 be used in a buck-boost configuration to generate negative output voltage?

Yes, LM2575T-15/LF03 can be configured as a positive-to-negative inverter per TI Application Note AN-1192. The fixed 15 V version is explicitly supported in this topology, using the same external components as the buck circuit but with reversed inductor and diode orientation. Output regulation remains ±4%, though efficiency drops ~5–8% versus standard buck operation due to added conduction losses in the inverted path.

What is the thermal resistance (θ_JA) of LM2575T-15/LF03 in its standard TO-220 package?

LM2575T-15/LF03 has a junction-to-ambient thermal resistance (θ_JA) of 65°C/W when mounted vertically on a PCB with minimal copper area, and 45°C/W with approximately 4 square inches of copper surrounding the leads. These values assume no external heatsink. For continuous 1 A operation at elevated ambient temperatures, thermal derating must be applied using the 125°C max junction temperature limit and measured board temperature rise.

Does LM2575T-15/LF03 require an external feedback resistor network?

No, LM2575T-15/LF03 does not require external feedback resistors. As a fixed-output variant, its internal resistor divider is factory-trimmed to deliver 15 V with ±4% tolerance. Pin 4 (Feedback) is internally connected and must remain unconnected in PCB layout - unlike the adjustable LM2575-ADJ version, which requires external R1/R2 to set V_OUT.

What type of catch diode is recommended for use with LM2575T-15/LF03?

Texas Instruments recommends a Schottky diode such as the SR103 or MBR340 for LM2575T-15/LF03, rated for ≥30 V reverse voltage and ≥1.2 A average forward current (≥1.15 × 1 A load). Schottky diodes minimize forward voltage drop (typically 0.4–0.5 V), reducing power loss and improving efficiency over fast-recovery silicon diodes. Layout must keep diode leads short to suppress ringing caused by parasitic inductance.