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

onsemi LM2575T-3.3G

Name: LM2575T-3.3G
Brand: onsemi
SKU: LM2575T-3.3G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LM2575T-3.3G

Manufacturer:: onsemi

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: TO-220-5

Datasheet:: LM2575T-3.3G.pdf

Description:: IC REG BUCK 3.3V 1A TO220-5

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Product details

Overview

LM2575T-3.3G from onsemi is a monolithic step-down (buck) switching regulator IC delivering a fixed 3.3 V output at up to 1.0 A, with ±4% output voltage tolerance over line and load, 4.75–40 V input range, and 52 kHz fixed-frequency operation. It integrates an internal 1.0 A switch, thermal shutdown, cycle-by-cycle current limiting, and TTL-compatible ON/OFF control-designed for high-efficiency DC-DC conversion in industrial power supplies and embedded systems.

For engineers reviewing the LM2575T-3.3G datasheet, pinout, applications, or equivalent options, key selection considerations include guaranteed 1.0 A output current, fixed 3.3 V output without external feedback resistors, TO-220-5 package with heatsink-capable Pin 3 (GND), and compatibility with standard off-the-shelf inductors (e.g., 330 µH) and Schottky catch diodes (e.g., 1N5819).

Technical Context

The LM2575T-3.3G implements a voltage-mode controlled buck converter with a built-in 52 kHz oscillator, 1.235 V bandgap reference, and error amplifier driving a 1.0 A NPN switch. Its internal architecture includes a 3.1 V internal regulator powering control circuitry, cycle-by-cycle current limit sensing, and thermal shutdown triggered at ~150°C junction temperature.

It operates in continuous conduction mode (CCM) across its rated load range, requiring only four external components: input capacitor (≥100 µF), output capacitor (≥330 µF), inductor (e.g., 330 µH), and Schottky catch diode (e.g., 1N5819). The ON/OFF pin enables logic-level shutdown with ≤80 µA standby current.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3 V ±4% (3.135–3.465 V) over −40°C to +125°C junction temp, 4.75–40 V input, 0.2–1.0 A load - eliminates need for feedback resistor network.
Max Output Current	1.0 A DC load current - sufficient for powering microcontrollers, FPGAs, and peripheral ICs without external current boosting.
Input Voltage Range	4.75 V to 40 V - supports wide-range unregulated inputs including 12 V/24 V industrial rails and automotive battery-supplied systems.
Switching Frequency	52 kHz (±10% over temp) - enables use of low-cost, high-saturation-current inductors and reduces EMI filtering complexity vs. MHz-class converters.
Efficiency	75% typical at 12 V_IN, 1.0 A_OUT - significantly higher than linear regulators, minimizing thermal dissipation and eliminating heatsink in many applications.
Standby Current	80 µA typical when ON/OFF pin = 5 V - enables low-power system sleep modes without disconnecting input supply.
Saturation Voltage	1.0 V typical (≤1.3 V max at −40°C to +125°C) - defines minimum dropout (V_IN − V_OUT) required for regulation; impacts thermal design at high I_LOAD.

Pinout & Package

LM2575T-3.3G uses the TO-220-5 (Case 314D) package with exposed heatsink surface electrically connected to Pin 3 (GND). This allows direct mounting to a heatsink while maintaining ground reference integrity and thermal performance (R_JC = 5.0°C/W).

Pin/Terminal	Circuit Role	Design Meaning
1 - Vin	Positive input supply	Accepts 4.75–40 V unregulated DC; requires local 100 µF low-ESR bypass capacitor to suppress switching transients and stabilize input impedance.
2 - Output	Emitter of internal NPN switch	Delivers regulated 3.3 V output; PCB copper area must be minimized to reduce coupling into sensitive analog circuits due to fast-switching node.
3 - GND	Circuit ground reference	Common return for input, output, feedback, and ON/OFF; serves as thermal interface to heatsink - must be low-impedance single-point connection.
4 - Feedback	Regulation sense input	Internally tied to fixed 3.3 V divider; not user-accessible - simplifies layout by removing external resistor network and associated noise pickup paths.
5 - ON/OFF	Logic-controlled enable/disable	TTL-compatible input: <1.4 V = ON, >2.2 V = OFF; draws ≤30 µA during active operation and drops total input current to ~80 µA in shutdown.

Key Features

Feature	Design Value
Fixed 3.3 V output	Eliminates external feedback resistors, reducing BOM count, layout sensitivity, and long-term drift errors in precision 3.3 V rail generation.
Integrated 1.0 A switch	Reduces external component count and board space vs. controller-only solutions; avoids gate-drive design complexity and MOSFET selection trade-offs.
Thermal shutdown & current limit	Provides autonomous fault protection under overload, short-circuit, or inadequate heatsinking - prevents catastrophic failure without external monitoring circuitry.
52 kHz fixed-frequency operation	Enables predictable EMI filtering, consistent inductor sizing, and stable loop compensation using standard ceramic or electrolytic capacitors.
TTL-compatible ON/OFF control	Allows direct interfacing with microcontroller GPIOs or system power sequencers without level-shifting, supporting dynamic power management.

Applications

Industrial Power Supply	Embedded Microcontroller Board
Use Scenario: Converting 24 V factory bus voltage to stable 3.3 V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary step-down regulator supplying core logic voltage to ARM Cortex-M4-based controllers and isolated CAN transceivers. Use Value: Delivers 1.0 A at 75% efficiency with no heatsink required below 50°C ambient, reducing thermal design overhead and enclosure size.	Use Scenario: Providing clean 3.3 V power to FPGA configuration memory, USB PHY, and real-time clock on compact edge-node PCBs. IC Role / Device Role / Timing Role: Main DC-DC converter enabling low-noise digital domain operation while supporting deep-sleep mode via ON/OFF pin. Use Value: Fixed 3.3 V output ensures consistent reset thresholds and I/O voltage levels; 80 µA standby current extends battery-backed operation.
Automotive Body Control Module	POS Terminal Power Management
Use Scenario: Regulating 12 V vehicle battery to 3.3 V for microcontroller, LIN transceiver, and LED driver ICs in door module assemblies. IC Role / Device Role / Timing Role: High-reliability buck regulator meeting AEC-Q100 stress requirements (NCV2575 variant); handles cold-crank down to 4.75 V. Use Value: Wide 4.75–40 V input range accommodates load-dump transients and cranking dips; thermal shutdown protects against sustained overloads.	Use Scenario: Generating 3.3 V from 5 V USB-C or 12 V wall adapter input in retail point-of-sale terminals with barcode scanners and thermal printers. IC Role / Device Role / Timing Role: Efficient pre-regulator feeding low-dropout linear regulators for noise-sensitive analog front-ends and audio amplifiers. Use Value: 52 kHz switching frequency avoids audible noise in consumer-facing devices; 330 µH inductor selection minimizes cost and footprint.

Industrial Power Supply

Embedded Microcontroller Board

Use Scenario: Converting 24 V factory bus voltage to stable 3.3 V for PLC I/O modules and sensor interfaces.

IC Role / Device Role / Timing Role: Primary step-down regulator supplying core logic voltage to ARM Cortex-M4-based controllers and isolated CAN transceivers.

Use Value: Delivers 1.0 A at 75% efficiency with no heatsink required below 50°C ambient, reducing thermal design overhead and enclosure size.

Use Scenario: Providing clean 3.3 V power to FPGA configuration memory, USB PHY, and real-time clock on compact edge-node PCBs.

IC Role / Device Role / Timing Role: Main DC-DC converter enabling low-noise digital domain operation while supporting deep-sleep mode via ON/OFF pin.

Use Value: Fixed 3.3 V output ensures consistent reset thresholds and I/O voltage levels; 80 µA standby current extends battery-backed operation.

Automotive Body Control Module

POS Terminal Power Management

Use Scenario: Regulating 12 V vehicle battery to 3.3 V for microcontroller, LIN transceiver, and LED driver ICs in door module assemblies.

IC Role / Device Role / Timing Role: High-reliability buck regulator meeting AEC-Q100 stress requirements (NCV2575 variant); handles cold-crank down to 4.75 V.

Use Value: Wide 4.75–40 V input range accommodates load-dump transients and cranking dips; thermal shutdown protects against sustained overloads.

Use Scenario: Generating 3.3 V from 5 V USB-C or 12 V wall adapter input in retail point-of-sale terminals with barcode scanners and thermal printers.

IC Role / Device Role / Timing Role: Efficient pre-regulator feeding low-dropout linear regulators for noise-sensitive analog front-ends and audio amplifiers.

Use Value: 52 kHz switching frequency avoids audible noise in consumer-facing devices; 330 µH inductor selection minimizes cost and footprint.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2575HVT-3.3	Higher 60 V max input voltage (vs. 40 V); same 3.3 V output, 1.0 A rating, and TO-220-5 package.	Better suited for 48 V telecom or industrial systems where transient overvoltage exceeds 40 V.	Select LM2575HVT-3.3 only if input can exceed 40 V; otherwise LM2575T-3.3G offers identical performance at lower cost.
MP1584EN-LF-Z	4.5–28 V input, adjustable output (0.8–25 V), 3 A capability, 1.5 MHz switching, SOIC-8 package.	Requires external feedback resistors; higher frequency enables smaller magnetics but increases EMI filtering demands.	Choose MP1584EN-LF-Z for higher current or adjustable output needs; LM2575T-3.3G remains optimal for fixed 3.3 V, 1 A, and legacy TO-220 layout compatibility.

Compared with LM2575HVT-3.3, the LM2575T-3.3G trades 20 V input headroom for cost and thermal simplicity in 12–24 V systems; versus MP1584EN-LF-Z, it offers plug-and-play fixed 3.3 V operation and proven ruggedness in industrial environments, albeit at lower switching frequency and current rating.

Availability

LM2575T-3.3G is available at Aetrix Electronics and suitable for industrial power supplies, embedded microcontroller boards, automotive body control modules, and POS terminal power management requiring stable component supply and long-term manufacturability.

Supply support for LM2575T-3.3G 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and cloud infrastructure markets.

The LM2575 series was designed as a robust, easy-to-use monolithic buck regulator family targeting cost-sensitive, high-reliability applications where minimal external components and proven thermal protection are critical - especially in industrial controls and automotive subsystems.

FAQ

What is the maximum input voltage rating for the LM2575T-3.3G?

The LM2575T-3.3G has an absolute maximum input voltage of 45 V, but its recommended operating input voltage range is 4.75 V to 40 V. Operation above 40 V risks exceeding guaranteed performance limits and may trigger internal protection mechanisms. For designs requiring >40 V input, the LM2575HVT-3.3 variant (60 V max) is the appropriate alternative.

Does the LM2575T-3.3G require external feedback resistors to set the output voltage?

No - the LM2575T-3.3G is a fixed-output version with internal resistor division configured for 3.3 V. Pin 4 (Feedback) is not accessible to the user and is internally connected. This eliminates resistor selection, placement, and drift concerns, simplifying design and improving long-term output stability compared to adjustable variants like LM2575-ADJ.

Can the LM2575T-3.3G operate without a heatsink?

Yes, the LM2575T-3.3G can operate without an external heatsink under typical conditions: at 12 V input, 1.0 A load, and ambient temperatures ≤50°C. Its thermal resistance (R_JA = 65°C/W) and 75% efficiency result in ~1.0 W dissipation, yielding ~65°C junction rise - within the 125°C max operating junction temperature. Higher input voltages or ambient temperatures require heatsinking.

What type of catch diode is recommended for use with the LM2575T-3.3G?

A Schottky diode such as the 1N5819 (30 V, 1 A) is recommended for the LM2575T-3.3G. Its low forward voltage (~0.45 V) minimizes conduction loss and improves efficiency, while its fast recovery prevents reverse-recovery spikes. Diode current rating should be ≥1.2× maximum load current (i.e., ≥1.2 A), and reverse voltage rating ≥1.25× maximum input voltage (e.g., ≥50 V for 40 V_IN).

How does the ON/OFF pin function on the LM2575T-3.3G?

The ON/OFF pin (Pin 5) provides TTL-compatible enable control: applying <1.4 V (typically 0 V) enables regulation, while applying >2.2 V (up to V_IN) disables the internal switch and reduces total input current to ~80 µA. This feature supports system-level power sequencing and low-power sleep states without disconnecting the main input supply.

LM2575T-3.3G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-5

Packaging:: Tube

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Fixed

Number of Outputs:: 1

Voltage - Input (Min):: 4.75V

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:: Through Hole

Supplier Device Package:: TO-220-5

LM2575T-3.3G FAQ

1.How can I place an order for LM2575T-3.3G through Aetrix?

Please submit a Request for Quotation (RFQ) for LM2575T-3.3G 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 LM2575T-3.3G reliable?

The price and inventory of LM2575T-3.3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2575T-3.3G is usually 5 days.

3.What payment methods are accepted for LM2575T-3.3G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575T-3.3G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LM2575T-3.3G?

LM2575T-3.3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM2575T-3.3G 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 LM2575T-3.3G?

For technical support, including LM2575T-3.3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575T-3.3G requirements.

6.How does Aetrix verify that LM2575T-3.3G is sourced from the original manufacturer or authorized distributors?

All LM2575T-3.3G 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 LM2575T-3.3G meets industry standards.

7.What is the process for return or replacement of LM2575T-3.3G?

All LM2575T-3.3G units undergo pre-shipment inspection (PSI). If there is an issue with LM2575T-3.3G, 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 LM2575T-3.3G part is unused and in its original packaging.

Return procedure for LM2575T-3.3G:

1.Submit a request within 90 days.

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

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