Texas Instruments LM2575MX-ADJ

Overview

LM2575MX-ADJ from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator with adjustable output, delivering stable DC-DC conversion across 1.23V–37V at ±4% output voltage accuracy. It operates from 40V input, integrates a 52 kHz fixed-frequency oscillator and internal current limiting, and targets board-level power conversion in industrial and embedded systems.

For engineers reviewing the LM2575MX-ADJ datasheet, LM2575MX-ADJ pinout, LM2575MX-ADJ application, or LM2575MX-ADJ equivalent, this page delivers verified technical context, package-specific pin definitions, real-world application mappings, and two validated alternative parts for design flexibility and supply continuity.

Technical Context

The LM2575MX-ADJ implements a self-contained buck topology with integrated NPN switch, thermal shutdown, cycle-by-cycle current limiting, and TTL-compatible ON/OFF control. Its feedback loop references a precise 1.23V internal bandgap, enabling programmable output via external resistor divider.

It requires only four external components - input capacitor, output capacitor, catch diode, and power inductor - and supports continuous conduction mode operation up to 1A load. The 52 kHz fixed switching frequency balances EMI control and inductor size, while the 98% max duty cycle enables low-dropout operation down to ~2.5V input for low-output-voltage designs.

Key Specifications

Pinout & Package

LM2575MX-ADJ is supplied in a 5-lead TO-220 package (package code NDH0005D), with exposed tab electrically connected to Pin 2 (Output). Thermal performance depends on PCB copper area: θ_JA = 65°C/W (minimal copper) or 45°C/W (4 in² copper).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2575MX-ADJ, LM2576MX-ADJ offers higher current headroom and identical compatibility, while MP1584EN-LF-Z trades integration and ruggedness for miniaturization-making LM2575MX-ADJ optimal for cost-sensitive, thermally constrained, and reliability-critical industrial use cases.

Availability

LM2575MX-ADJ is available at Aetrix Electronics and suitable for industrial power supplies, embedded system pre-regulators, and on-card DC-DC converters requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for LM2575MX-ADJ 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 heritage in reliable, production-ready power ICs.

The LM2575MX-ADJ belongs to TI's SIMPLE SWITCHER® family-designed specifically for ease-of-use, minimal external component count, and robust operation in industrial, automotive, and telecom power applications.

FAQ

What is the maximum input voltage rating for LM2575MX-ADJ?

The absolute maximum input voltage for LM2575MX-ADJ is 45V, but its specified operating range is up to 40V. Exceeding 40V risks violating the device's electrical characteristics and may trigger thermal shutdown or reduce long-term reliability. Always maintain ≥1V margin below 45V in final designs, and verify transient behavior with input clamping if used in 36V nominal systems.

How do I calculate the output voltage setting resistors for LM2575MX-ADJ?

Use the formula V_OUT = 1.23V × (1 + R2/R1), where R1 connects from Feedback (Pin 4) to Ground and R2 connects from Output (Pin 2) to Feedback (Pin 4). Select R1 between 1 kΩ and 5 kΩ (1% metal film recommended); then compute R2. For example, for 12V output with R1 = 2.2 kΩ, R2 = 2.2 kΩ × ((12/1.23) − 1) ≈ 19.3 kΩ → use 19.1 kΩ (1%). LM2575MX-ADJ's 50 nA feedback bias current makes resistor value choice critical for accuracy.

Does LM2575MX-ADJ require an external diode, and what type is recommended?

Yes, LM2575MX-ADJ requires an external Schottky catch diode connected from Output (Pin 2) to Ground. Recommended parts include MBR340 (40V, 3A) or SR103 (30V, 1A), selected for low forward voltage (<0.5V) and fast recovery to minimize conduction loss and switching stress. Diode reverse voltage rating must exceed the input voltage by ≥25%, and current rating should be ≥1.2× the maximum load current.

Can LM2575MX-ADJ be used in a buck-boost (inverting) configuration?

Yes, LM2575MX-ADJ can be configured as a positive-to-negative inverter per TI Application Note SLVA017. In this topology, the IC regulates the magnitude of the negative output voltage referenced to ground, using the same external components as the buck configuration but with modified connections. Output polarity inversion is achieved without adding active devices-only passive re-routing of inductor and diode-making it a proven solution for generating –5V or –12V rails from single positive inputs.

What thermal considerations apply to LM2575MX-ADJ in TO-220 package?

LM2575MX-ADJ in TO-220 (NDH0005D) has θ_JA = 65°C/W with minimal PCB copper, dropping to 45°C/W with ~4 in² of copper pour under the tab. To sustain 1A continuous output at 40V_IN/5V_OUT, junction temperature must stay ≤125°C. At 77% efficiency, power dissipation is ~1.5W; with θ_JA = 45°C/W, rise is ~68°C above ambient-requiring ≤57°C ambient for safe operation. Use thermal vias and copper fill to maximize heat transfer from the tab (Pin 2) to inner layers.