Texas Instruments LM2575T-15

Overview

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

For engineers reviewing the LM2575T-15 datasheet, LM2575T-15 pinout, LM2575T-15 application, or LM2575T-15 equivalent, key selection criteria include its 52 kHz fixed-frequency operation, thermal shutdown, cycle-by-cycle current limiting, TTL-compatible shutdown, and compatibility with standard off-the-shelf inductors - all critical for reliable, low-component-count buck converter design.

Technical Context

The LM2575T-15 implements a fixed-frequency (52 kHz) current-mode PWM architecture with internal oscillator, error amplifier, and N-channel DMOS power switch. Its feedback loop references a precise 1.23V internal bandgap, comparing output via resistive divider only in adjustable versions - the LM2575T-15 uses internal resistor network to fix V_OUT at 15V.

Protection features include thermal shutdown triggered at 150°C junction temperature, cycle-by-cycle peak current limiting (1.7–3.2 A), and 50 μA typical standby current during TTL-level OFF control. Input voltage range is 18V to 40V for nominal operation, with dropout behavior defined by minimum on-time and saturation voltage (0.9 V typ, 1.4 V max at 1A).

Key Specifications

Pinout & Package

LM2575T-15 is housed in a 5-lead TO-220 package (Package Number NDH0005D) with integrated heat slug. Pin 3 is internally connected to the die substrate and must be electrically tied to input ground for thermal and EMI performance.

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, the LM2575T-15 delivers optimal trade-off between ruggedness, simplicity, and cost for 24 V input industrial applications - retaining full protection features and TO-220 thermal performance without requiring layout changes or component requalification.

Availability

LM2575T-15 is available at Aetrix Electronics and suitable for industrial power supplies, embedded system pre-regulators, on-card DC/DC conversion, and positive-to-negative converter designs requiring stable component supply and long-term manufacturability.

Supply support for LM2575T-15 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 switching regulator design and manufacturing.

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

FAQ

What is the maximum input voltage for the LM2575T-15?

The LM2575T-15 supports a maximum input voltage of 40 V under normal operating conditions. Absolute maximum rating is 45 V, but sustained operation above 40 V risks exceeding thermal limits or violating specified electrical characteristics. For inputs up to 60 V, the LM2575HVT-15 variant is recommended. Always verify input transient margins and ensure adequate derating per application environment when using LM2575T-15.

Does the LM2575T-15 require an external feedback resistor network?

No, the LM2575T-15 does not require external feedback resistors. It is a fixed-output version with internal resistor divider setting V_OUT to 15 V. Pin 4 (FEEDBACK) is internally connected and must remain unconnected in circuit - unlike the adjustable LM2575-ADJ variant. This simplifies design and improves stability, as the LM2575T-15's feedback path is fully integrated and factory-trimmed.

Can the LM2575T-15 be used in a buck-boost (inverting) configuration?

Yes, the LM2575T-15 can be configured as a positive-to-negative converter (inverting buck-boost) by rearranging external components - using the switch node (Pin 2) to drive an inductor to ground, with output taken from the inductor-diode junction referenced to input ground. TI Application Note SNVA003 provides validated schematics and layout guidance. The LM2575T-15's robust current limit and thermal protection remain fully functional in this topology.

What is the thermal performance of the LM2575T-15 in TO-220 package without a heatsink?

The LM2575T-15 in TO-220 has θ_JA = 65 °C/W with minimal copper (½-inch leads, socket mount) and 45 °C/W with ~4 in² of PCB copper area. At 1 A output and 24 V input, typical power dissipation is ~1.2 W - resulting in ~78°C rise above ambient with minimal copper. For continuous 1 A operation at elevated ambient, a heatsink or ≥2 in² copper pour is strongly advised. Thermal shutdown activates at 150°C junction temperature.

Is the LM2575T-15 pin-compatible with other LM2575 variants like LM2575-ADJ or LM2575-5.0?

Yes, all LM2575 variants in the TO-220 package (including LM2575T-15, LM2575T-5.0, and LM2575T-ADJ) share identical pinout and mechanical footprint. However, internal connections differ: the ADJ version requires external resistors on Pin 4, while fixed versions like LM2575T-15 leave Pin 4 unconnected. Swapping variants requires updating external components - especially feedback and output capacitor values - but no PCB redesign is needed.