Texas Instruments LM2575T-12/NOPB

Overview

LM2575T-12/NOPB from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator with fixed 12V output, 40V maximum input voltage, 52 kHz internal oscillator, 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 LM2575T-12/NOPB datasheet, LM2575T-12/NOPB pinout, LM2575T-12/NOPB application, or LM2575T-12/NOPB equivalent, this device is selected for cost-sensitive 12V DC-DC conversion where input ranges from 15V to 40V, output load reaches 1A, and thermal management without a heatsink is required under typical PCB copper area.

Technical Context

The LM2575T-12/NOPB implements a fixed-frequency pulse-width modulation (PWM) buck topology with an internal NPN power switch, feedback comparator referenced to 1.23V, and built-in 52 kHz oscillator. Regulation is achieved via voltage-mode control using a single-resistor feedback network tied to the output.

It features TTL-compatible ON/OFF control with 50 μA standby current, cycle-by-cycle peak current limiting at 2.2A typical, and thermal shutdown activation at 150°C junction temperature. The device operates across −40°C to +125°C junction range and requires only four external components: input capacitor, output capacitor, catch diode, and inductor.

Key Specifications

Pinout & Package

LM2575T-12/NOPB uses a 5-lead TO-220 package (package number NDH0005D) with exposed tab electrically connected to Pin 2 (Output). The tab serves as primary thermal path and must be soldered to a copper pour for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2575HVT-12/NOPB, the LM2575T-12/NOPB trades 20V input headroom for lower unit cost and qualification maturity; versus MP1584EN-LF-Z, it provides simpler implementation with internal compensation and proven thermal robustness in through-hole industrial assemblies.

Availability

LM2575T-12/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, embedded controller boards, test equipment modules, and legacy system retrofits requiring stable component supply and long-lifecycle support.

Supply support for LM2575T-12/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 reliable, high-volume power IC design.

The LM2575 series was engineered as a SIMPLE SWITCHER® solution to replace linear regulators in cost-sensitive, medium-power DC-DC applications-emphasizing ease of use, thermal resilience, and minimal external component count.

FAQ

What is the maximum input voltage rating for LM2575T-12/NOPB?

The LM2575T-12/NOPB has a maximum input voltage rating of 40V, as specified in the Absolute Maximum Ratings table. Operation above this voltage risks permanent damage. This distinguishes it from the LM2575HVT-12/NOPB variant, which supports up to 60V. For designs with nominal 24V inputs subject to transients, ensure clamping or filtering keeps VIN within 40V at the LM2575T-12/NOPB input pin.

Does LM2575T-12/NOPB require an external feedback resistor network?

No, the LM2575T-12/NOPB is a fixed-output version with internal resistor divider set for 12V regulation; Pin 4 (Feedback) is not user-accessible and is internally connected. External resistors are only required for the adjustable LM2575-ADJ variant. Using LM2575T-12/NOPB eliminates tuning error, temperature drift, and layout sensitivity associated with external feedback networks.

What thermal performance can be expected from LM2575T-12/NOPB in a TO-220 package without a heatsink?

In a standard TO-220 mounting configuration with minimal copper (½-inch leads, socket or minimal PCB copper), LM2575T-12/NOPB exhibits θJA = 65°C/W. At 1A output into 12V with 24V input (12W input power, ~1.4W dissipation), junction temperature rise is ~91°C above ambient-well within the 125°C max operating limit if ambient stays below 34°C. Adding 4 in² copper area reduces θJA to 45°C/W, enabling full 1A operation up to 70°C ambient.

Can LM2575T-12/NOPB be used in synchronous rectification configurations?

No, the LM2575T-12/NOPB uses an internal NPN bipolar transistor and requires an external catch diode (e.g., Schottky SR103 or MBR340). It does not support synchronous rectification because it lacks a second gate drive output or control logic for a low-side MOSFET. Synchronous operation would require a different controller IC such as the TPS5430 or LM2678, which provide complementary high-side/low-side drive signals.

Is LM2575T-12/NOPB RoHS compliant and lead-free?

Yes, the /NOPB suffix explicitly denotes "No Lead (Pb)-Free" and RoHS-compliant packaging. LM2575T-12/NOPB meets JEDEC J-STD-020 moisture sensitivity level 3 and is qualified for lead-free reflow soldering per IPC/JEDEC J-STD-020. The device uses matte tin lead finish and complies with EU RoHS Directive 2011/65/EU and China RoHS.