Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Microchip Technology LM2575-3.3BU TR

Name: LM2575-3.3BU TR
Brand: Microchip Technology
SKU: LM2575-3.3BU TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: LM2575-3.3BU TR

Manufacturer:: Microchip Technology

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: TO-263-6, D2PAK (5 Leads + Tab), TO-263BA

Datasheet:: LM2575-3.3BU TR.pdf

Description:: IC REG BUCK 3.3V 1A TO263-5

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:2,288

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

LM2575-3.3BU TR from Micrel is a fixed-output 3.3V, 1A step-down (buck) switching regulator in TO-263 package with 52kHz fixed-frequency operation, ±3% output voltage tolerance over load and line, and integrated thermal shutdown and cycle-by-cycle current limiting. It replaces linear regulators in industrial power supplies requiring compact, high-efficiency DC-DC conversion.

For engineers reviewing the LM2575-3.3BU TR datasheet, LM2575-3.3BU TR pinout, LM2575-3.3BU TR application, or LM2575-3.3BU TR equivalent, key selection factors include guaranteed 1A output current, 4V–40V input range, TO-263 thermal performance (θ_JA = 45°C/W), and compatibility with standard off-the-shelf inductors for rapid design implementation.

Technical Context

The LM2575-3.3BU TR integrates a 52kHz oscillator, error amplifier, bandgap reference (1.23V), PWM comparator, and 1A NPN switch driver in a monolithic buck topology. Its fixed 3.3V output eliminates external feedback resistors, simplifying layout versus adjustable variants.

Internal protection includes thermal shutdown triggered at 150°C junction temperature and cycle-by-cycle current limiting with 1.7A minimum peak current threshold. Standby quiescent current is ≤200µA when ON/OFF pin is pulled high, enabling low-power system control.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3V ±3% over 0.2A–1A load and 8V–40V input - ensures stable logic supply without trimming.
Max Output Current	1A continuous - supports microcontroller cores, FPGAs, and peripheral rails without external current boosting.
Input Voltage Range	4V to 40V - accommodates 5V, 12V, 24V, and 36V industrial bus inputs with margin.
Switching Frequency	52kHz ±10% - enables use of low-cost, high-saturation-current inductors (e.g., 330µH) and reduces EMI filtering complexity.
Efficiency	75% at 12V_IN/3.3V_OUT/1A - cuts heat generation vs. linear regulators, eliminating need for heatsinks in many applications.
Thermal Resistance	θ_JA = 45°C/W (TO-263 on 4 in² copper) - enables 1A operation up to +85°C ambient without forced air.
Standby Current	<200µA - allows clean power sequencing and battery-backed sleep modes.

Pinout & Package

Package: TO-263 (5-pin, surface-mount, exposed thermal pad). Pin 1: VIN; Pin 2: OUTPUT; Pin 3: GND; Pin 4: FEEDBACK (internally tied to 3.3V reference); Pin 5: ON/OFF.

Pin/Terminal	Circuit Role	Design Meaning
1 - VIN	Unregulated input supply connection	Accepts 4V–40V DC; requires ≥100µF bulk capacitance near pin to suppress switching transients.
2 - OUTPUT	Regulated 3.3V output node	Drives load directly; connects to catch diode anode and output capacitor cathode in standard buck layout.
3 - GND	Power and signal ground reference	Must be low-impedance connection to PCB ground plane; shared return for input/output capacitors and catch diode.
4 - FEEDBACK	Internal voltage sense point	Floating for fixed 3.3V version; no external resistor network required - reduces BOM count and layout sensitivity.
5 - ON/OFF	Logic-controlled enable/disable input	Active-low: <0.8V = ON, >2.4V = OFF; draws ≤10µA in ON state, enabling microcontroller GPIO control.

Key Features

Feature	Design Value
Fixed 3.3V output	Eliminates feedback resistor network, reducing component count, layout area, and calibration drift risk.
Integrated current limiting	1.7A minimum peak current limit protects against short-circuit and overload without external sensing components.
Thermal shutdown	Automatically disables switching at 150°C junction temperature and resumes after cooldown - prevents permanent damage.
Low standby current	≤200µA shutdown current enables energy-sensitive applications like battery-powered sensors and remote I/O.
Standard inductor compatibility	Optimized for 330µH, 1.5A+ saturation current inductors - avoids custom magnetics and accelerates prototyping.

Applications

Industrial PLC Power Rails	Embedded Controller Core Supply
Use Scenario: Providing clean 3.3V power to ARM Cortex-M4 microcontrollers and CAN transceivers in programmable logic controllers. IC Role / Device Role / Timing Role: Primary buck regulator converting 24V field bus to isolated 3.3V logic rail. Use Value: Delivers 1A at 75% efficiency with no heatsink required, reducing enclosure size and thermal management cost.	Use Scenario: Powering FPGA configuration circuitry and DDR memory interfaces in edge-computing gateways. IC Role / Device Role / Timing Role: High-current, low-noise DC-DC converter meeting tight 3.3V ±3% regulation for digital I/O banks. Use Value: Fixed output eliminates resistor tolerance errors, ensuring consistent startup timing and voltage-margin compliance.
On-Board 3.3V Conversion	Pre-Regulator for LDOs
Use Scenario: Generating local 3.3V supply from 12V backplane in telecom line cards and data acquisition modules. IC Role / Device Role / Timing Role: Compact, surface-mount buck stage replacing through-hole linear regulators on dense PCBs. Use Value: TO-263 package provides superior thermal performance vs. TO-220 in space-constrained layouts.	Use Scenario: Reducing 24V input to ~5V before feeding low-dropout linear regulators for noise-sensitive analog circuits. IC Role / Device Role / Timing Role: Efficient pre-regulator minimizing power dissipation in downstream LDOs. Use Value: 75% efficiency at 1A lowers total system heat by >3W versus direct 24V-to-3.3V linear regulation.

Industrial PLC Power Rails

Embedded Controller Core Supply

Use Scenario: Providing clean 3.3V power to ARM Cortex-M4 microcontrollers and CAN transceivers in programmable logic controllers.

IC Role / Device Role / Timing Role: Primary buck regulator converting 24V field bus to isolated 3.3V logic rail.

Use Value: Delivers 1A at 75% efficiency with no heatsink required, reducing enclosure size and thermal management cost.

Use Scenario: Powering FPGA configuration circuitry and DDR memory interfaces in edge-computing gateways.

IC Role / Device Role / Timing Role: High-current, low-noise DC-DC converter meeting tight 3.3V ±3% regulation for digital I/O banks.

Use Value: Fixed output eliminates resistor tolerance errors, ensuring consistent startup timing and voltage-margin compliance.

On-Board 3.3V Conversion

Pre-Regulator for LDOs

Use Scenario: Generating local 3.3V supply from 12V backplane in telecom line cards and data acquisition modules.

IC Role / Device Role / Timing Role: Compact, surface-mount buck stage replacing through-hole linear regulators on dense PCBs.

Use Value: TO-263 package provides superior thermal performance vs. TO-220 in space-constrained layouts.

Use Scenario: Reducing 24V input to ~5V before feeding low-dropout linear regulators for noise-sensitive analog circuits.

IC Role / Device Role / Timing Role: Efficient pre-regulator minimizing power dissipation in downstream LDOs.

Use Value: 75% efficiency at 1A lowers total system heat by >3W versus direct 24V-to-3.3V linear regulation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2575-3.3BT	Same electrical specs but TO-220 package (θ_JA = 65°C/W); no exposed thermal pad.	Requires heatsink above ~0.6A in still air; less suitable for high-density SMT assemblies.	Select LM2575-3.3BT only if through-hole mounting or legacy board compatibility is required.
MP1584EN-LF-Z	3.3V fixed, 3A output, 1.5MHz switching, smaller SOIC-8 package; no ON/OFF pin.	Higher frequency enables smaller inductors/capacitors but increases EMI filtering demands; lacks enable control.	Choose MP1584EN-LF-Z when higher current or smaller footprint is critical and enable functionality is not needed.

Compared with LM2575-3.3BT, the LM2575-3.3BU TR offers 20°C/W lower thermal resistance for same-current operation; versus MP1584EN-LF-Z, it trades higher current and frequency for proven 52kHz EMI behavior and integrated ON/OFF control - making LM2575-3.3BU TR optimal for industrial designs prioritizing reliability, thermal headroom, and system-level power sequencing.

Availability

LM2575-3.3BU TR is available at Aetrix Electronics and suitable for industrial automation, embedded controller power, and telecom infrastructure requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LM2575-3.3BU 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 robust industrial-grade products and clear documentation.

The LM2575 series was designed as a drop-in, high-efficiency replacement for three-terminal linear regulators in industrial and embedded systems - emphasizing simplicity, thermal resilience, and minimal external component count.

FAQ

What is the maximum input voltage rating for LM2575-3.3BU TR?

The absolute maximum input voltage for LM2575-3.3BU TR is 45V, but the recommended operating range is 4V to 40V. Exceeding 40V risks violating the device's internal transistor breakdown limits and may trigger premature thermal shutdown. For reliable 36V nominal systems, LM2575-3.3BU TR provides sufficient margin while maintaining full 1A output capability across temperature.

Does LM2575-3.3BU TR require an external feedback resistor network?

No, LM2575-3.3BU TR does not require external feedback resistors. As a fixed-output variant, its internal feedback node is trimmed to 3.3V and connected internally - eliminating resistor matching errors, temperature drift, and layout sensitivity. This distinguishes it from adjustable versions like LM2575 and simplifies design validation.

How does the ON/OFF pin function on LM2575-3.3BU TR?

The ON/OFF pin (Pin 5) on LM2575-3.3BU TR is active-low: pulling it below 0.8V enables regulation, while pulling it above 2.4V disables switching and reduces quiescent current to ≤200µA. It draws ≤10µA when enabled, allowing direct interfacing with 3.3V or 5V microcontroller GPIOs without level shifting.

What thermal performance can be expected from LM2575-3.3BU TR in a typical PCB layout?

With 4 in² of 2-oz copper connected to the TO-263 exposed pad, LM2575-3.3BU TR achieves θ_JA = 45°C/W. At 1A output and 12V input, power dissipation is ~8.7W; this yields ~390°C rise above ambient - but actual junction temperature remains within safe limits due to thermal shutdown activation at 150°C. Derating to 0.8A ensures continuous operation at +85°C ambient.

Can LM2575-3.3BU TR be used in negative-output (inverting) configurations?

Yes, LM2575-3.3BU TR supports inverting buck-boost topologies to generate negative voltages, as documented in Micrel's application notes. However, the fixed 3.3V feedback reference constrains output magnitude to |V_OUT| ≈ 3.3V × (R₁/R₂ + 1); achieving precise negative rails requires careful compensation and external components - unlike adjustable versions optimized for such use cases.

LM2575-3.3BU TR Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: TO-263-6, D2PAK (5 Leads + Tab), TO-263BA

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Fixed

Number of Outputs:: 1

Voltage - Input (Min):: 4V

Voltage - Input (Max):: 40V

Voltage - Output (Min/Fixed):: 3.3V

Voltage - Output (Max):: -

Current - Output:: 1A

Frequency - Switching:: 52kHz

Synchronous Rectifier:: No

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: TO-263-5

LM2575-3.3BU TR FAQ

1.How can I place an order for LM2575-3.3BU TR through Aetrix?

Please submit a Request for Quotation (RFQ) for LM2575-3.3BU TR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LM2575-3.3BU TR reliable?

The price and inventory of LM2575-3.3BU TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2575-3.3BU TR is usually 5 days.

3.What payment methods are accepted for LM2575-3.3BU TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575-3.3BU TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LM2575-3.3BU TR?

LM2575-3.3BU TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM2575-3.3BU TR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LM2575-3.3BU TR?

For technical support, including LM2575-3.3BU TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575-3.3BU TR requirements.

6.How does Aetrix verify that LM2575-3.3BU TR is sourced from the original manufacturer or authorized distributors?

All LM2575-3.3BU TR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM2575-3.3BU TR meets industry standards.

7.What is the process for return or replacement of LM2575-3.3BU TR?

All LM2575-3.3BU TR units undergo pre-shipment inspection (PSI). If there is an issue with LM2575-3.3BU TR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LM2575-3.3BU TR part is unused and in its original packaging.

Return procedure for LM2575-3.3BU TR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…