Microchip Technology LM2576-5.0WU-TR

Overview

LM2576-5.0WU-TR from Micrel is a fixed-output 5.0V, 3A step-down (buck) switching regulator in TO-263-5 package, featuring 52kHz fixed-frequency operation, ±3% output voltage tolerance over line/load/temperature, and integrated 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 LM2576-5.0WU-TR datasheet, LM2576-5.0WU-TR pinout, LM2576-5.0WU-TR application, or LM2576-5.0WU-TR equivalent, key selection criteria include input voltage range (4V–40V), guaranteed 3A output current, standby quiescent current <200µA, and compatibility with standard off-the-shelf inductors for rapid design implementation.

Technical Context

The LM2576-5.0WU-TR integrates a 52kHz oscillator, error amplifier, bandgap reference (1.23V), PWM comparator, and 3A NPN switch with saturation voltage ≤2.0V at full load. Its feedback loop uses internal compensation and requires only two external resistors for adjustable variants - but is internally trimmed for fixed 5.0V output.

Thermal protection activates at ~150°C junction temperature, and current limiting triggers at ≥4.2A peak switch current. The ON/OFF pin supports logic-level shutdown with <30µA leakage and 1.0V max low-level threshold, enabling system-level power sequencing without external circuitry.

Key Specifications

Pinout & Package

LM2576-5.0WU-TR uses the 5-lead TO-263 (D²PAK) surface-mount package with exposed thermal pad. Pin 3 is GND and serves as primary thermal path; pins 1 (VIN), 2 (OUTPUT), 4 (FEEDBACK), and 5 (ON/OFF) are signal terminals. Mounting requires soldering the tab to a ≥1 in² copper area for θ_JA ≈ 45°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2576-5.0T-TR, the LM2576-5.0WU-TR offers superior thermal performance in SMT layouts and eliminates lead-forming steps; versus MP1584EN-LF-Z, it trades higher-frequency size reduction for simpler implementation, proven reliability, and direct 5V output without resistor calibration.

Availability

LM2576-5.0WU-TR is available at Aetrix Electronics and suitable for industrial automation power supplies, automotive body electronics, embedded networking hardware, and medical handheld devices requiring stable component supply across multi-year production cycles.

Supply support for LM2576-5.0WU-TR 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

Micrel, Inc. was a U.S.-based semiconductor company specializing in power management, analog, and mixed-signal ICs before its acquisition by Microchip Technology in 2015. Known for rugged, application-ready regulators and timing solutions.

The LM2576 series was designed as a drop-in, high-efficiency replacement for three-terminal linear regulators in industrial and automotive power conversion - prioritizing simplicity, thermal robustness, and minimal external component count.

FAQ

What is the maximum input voltage rating for the LM2576-5.0WU-TR?

The LM2576-5.0WU-TR has an absolute maximum input voltage of 45V, with recommended operating range up to 40V. This allows reliable operation in 24V industrial systems experiencing load dump transients or 36V nominal battery inputs. Exceeding 40V continuously risks exceeding thermal limits or triggering internal protection, so design margin should maintain VIN ≤ 40V under worst-case conditions. The LM2576-5.0WU-TR datasheet specifies 4V–40V as the functional input range.

Does the LM2576-5.0WU-TR require external feedback resistors to set the 5V output?

No - the LM2576-5.0WU-TR is a fixed-output variant with internal feedback divider trimmed to deliver precisely 5.0V. Pin 4 (FEEDBACK) is internally connected to the output and must not be externally loaded or disconnected; doing so will disrupt regulation. Unlike adjustable versions (e.g., LM2576-ADJ), the LM2576-5.0WU-TR needs no external resistors, reducing part count and improving accuracy over temperature.

How does the ON/OFF pin function on the LM2576-5.0WU-TR?

The ON/OFF pin (Pin 5) provides logic-level enable control: applying ≤1.0V (typically 0V) turns the LM2576-5.0WU-TR ON, while ≥2.2V (typically 3.3V or 5V) forces shutdown with <200µA quiescent current. It features <30µA leakage and supports direct interfacing with MCU GPIOs. The LM2576-5.0WU-TR remains latched in its state until the pin voltage crosses the hysteresis threshold, enabling clean power sequencing in multi-rail systems.

What thermal management is required for the LM2576-5.0WU-TR at full 3A load?

At 3A output and 12V input, the LM2576-5.0WU-TR dissipates ~2.1W. With θ_JA ≈ 45°C/W (PCB copper area ≥1 in²), junction temperature rise is ~95°C above ambient - requiring ambient ≤55°C for safe operation below 150°C max T_J. Use of thermal vias under the exposed pad and ≥2 oz copper improves heat transfer. The LM2576-5.0WU-TR integrates thermal shutdown at ~150°C, but derating is advised for long-term reliability.

Can the LM2576-5.0WU-TR be used in negative-output (inverting) configurations?

Yes - the LM2576-5.0WU-TR supports inverting buck-boost topology to generate negative voltages, as documented in Micrel's application notes. In this configuration, the OUTPUT pin becomes the negative rail, GND becomes the return, and the inductor/diode/capacitor connections are rearranged. Output magnitude remains regulated at 5V, but polarity reverses. The LM2576-5.0WU-TR maintains its 3A capability and protection features in this mode, though efficiency drops ~5–10% versus standard buck.