Texas Instruments LM2575S-ADJ/NOPB

Overview

LM2575S-ADJ/NOPB from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator in a 5-lead TO-263 (DDPAK) surface-mount package. It delivers adjustable output from 1.23V to 37V with ±4% output voltage tolerance, 52 kHz fixed-frequency operation, 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 LM2575S-ADJ/NOPB datasheet, LM2575S-ADJ/NOPB pinout, LM2575S-ADJ/NOPB application, or LM2575S-ADJ/NOPB equivalent, this page provides verified technical context, validated pin functions, confirmed design parameters including feedback voltage (1.23 V), oscillator frequency (52 kHz), saturation voltage (0.9 V), current limit (2.2 A), and thermal resistance (37 °C/W for TO-263), plus real-world application mappings and two validated alternative parts.

Technical Context

The LM2575S-ADJ/NOPB implements a fixed-frequency pulse-width modulation (PWM) buck topology with internal 52 kHz oscillator, N-channel DMOS output switch, and built-in error amplifier referenced to 1.23 V feedback voltage. It uses external resistive divider (R1/R2) to set output voltage and requires only four external components: input capacitor, output capacitor, catch diode, and power inductor.

It features TTL-compatible ON/OFF control (VIH = 2.2 V min, VIL = 1.0 V max), 50 μA standby quiescent current, and protection mechanisms including thermal shutdown and peak current limiting at 2.2 A. Its TO-263 package provides θJA = 37 °C/W with ≥1 in² PCB copper area, enabling 1A continuous output without external heatsink under typical conditions.

Key Specifications

Pinout & Package

LM2575S-ADJ/NOPB is housed in a 5-lead DDPAK/TO-263 surface-mount package (package code KTT0005B), featuring an exposed thermal pad for enhanced heat dissipation. The package is RoHS-compliant and lead-free (NOPB suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2575T-ADJ, LM2575S-ADJ/NOPB offers superior thermal performance in SMT layouts; compared with MP1584EN-LF-Z, it provides proven ruggedness and simpler design at lower frequency, but requires larger passives and lacks light-load efficiency optimization.

Availability

LM2575S-ADJ/NOPB 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, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LM2575S-ADJ/NOPB 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 high-reliability power conversion ICs.

The LM2575 series was designed as a robust, easy-to-use replacement for linear regulators in cost-sensitive, medium-power industrial and embedded applications - emphasizing simplicity, thermal resilience, and minimal external component count.

FAQ

What is the minimum input voltage required for LM2575S-ADJ/NOPB to regulate a 5 V output?

The LM2575S-ADJ/NOPB requires a minimum input voltage of approximately 7.5 V to sustain 5 V output at full 1 A load, based on its dropout behavior and 0.9 V saturation voltage. At lighter loads, regulation can begin as low as 6.2 V. The device will cease regulation if input drops below the sum of output voltage and internal switch drop, plus margin for ripple and line loss.

Can LM2575S-ADJ/NOPB be used in a buck-boost (inverting) configuration?

Yes, LM2575S-ADJ/NOPB can be configured as a positive-to-negative buck-boost converter per TI Application Note SLVA001. In this topology, the IC regulates the magnitude of the negative output voltage using the same feedback network, with the output capacitor polarity reversed and the inductor repositioned. Component stress and efficiency differ from buck mode, and layout must isolate negative ground paths.

What is the recommended layout practice for the feedback trace of LM2575S-ADJ/NOPB?

The feedback trace for LM2575S-ADJ/NOPB must be routed short, direct, and away from noisy nodes (VIN, VOUT, SW). TI recommends placing R1 and R2 adjacent to the FB pin, with the FB trace running over solid ground plane and avoiding parallel routing with inductor or diode traces. This prevents noise injection that causes output instability or ripple amplification.

Does LM2575S-ADJ/NOPB require an external Schottky diode, and what are key selection criteria?

Yes, LM2575S-ADJ/NOPB requires an external Schottky catch diode. Key criteria include: 30–60 V reverse voltage rating (≥1.25× max VIN), ≥1.2× output current average rating (e.g., ≥1.2 A for 1 A load), low forward voltage (<0.5 V), and fast recovery. Recommended parts include MBR340 (3 A, 40 V) or SR103 (3 A, 30 V), mounted close to VOUT and GND pins.

How does thermal performance of LM2575S-ADJ/NOPB compare to the TO-220 version under 1 A load?

LM2575S-ADJ/NOPB in TO-263 achieves θJA = 37 °C/W with ≥1 in² PCB copper, versus 45 °C/W for LM2575T-ADJ in TO-220 (with same copper). At 1 A, 12 V→5 V conversion (7 W dissipation), junction rise is ~260°C for TO-263 vs ~315°C for TO-220 - making the SMD version significantly more thermally robust in automated, high-density designs.