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onsemi LM2575T-3.3
- Part No.:
- LM2575T-3.3
- Manufacturer:
- onsemi
- Package:
- TO-220-5
- Datasheet:
-
LM2575T-3.3.pdf
- Description:
- IC REG BUCK 3.3V 1A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,605
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Product details
Overview
LM2575T-3.3 from onsemi is a monolithic step-down (buck) switching regulator IC delivering 1.0 A output current with fixed 3.3 V output, ±4% output voltage tolerance over line and load, and 52 kHz internal oscillator frequency. It operates from 4.75 V to 40 V input and integrates thermal shutdown, cycle-by-cycle current limiting, and TTL-compatible ON/OFF control - used in embedded power supplies requiring high efficiency over linear regulators.
For engineers reviewing the LM2575T-3.3 datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed 1.0 A output capability, no heatsink requirement under typical loads, fixed-output simplicity versus adjustable versions, and compatibility with standard off-the-shelf 330 µH inductors and Schottky catch diodes.
Technical Context
The LM2575T-3.3 implements a voltage-mode controlled buck converter with an integrated 1.0 A NPN switch, 1.235 V bandgap reference, error amplifier, and 52 kHz oscillator. Its feedback loop uses internal resistor division for fixed 3.3 V output - eliminating external programming resistors required by the adjustable version.
Protection architecture includes cycle-by-cycle peak current limiting (1.7–3.0 A typical), thermal shutdown at ~150°C junction temperature, and 80 µA standby quiescent current when ON/OFF pin is pulled high. The device supports continuous conduction mode operation and requires only four external components: input capacitor, output capacitor, inductor, and catch diode.
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), enabling direct replacement of LDOs in 3.3 V logic rails. |
| Output Current | Guaranteed 1.0 A DC load current, sufficient for powering microcontrollers, FPGAs, and peripheral ICs without derating. |
| Input Voltage Range | 4.75 V to 40 V DC, supporting wide-input industrial, automotive, and battery-derived supplies (e.g., 12 V or 24 V bus). |
| Switching Frequency | 52 kHz fixed internal oscillator (±10% over temperature), enabling use of low-cost, high-saturation-current inductors with minimal EMI filtering. |
| Efficiency | 75% typical at 12 VIN/3.3 VOUT/1.0 A, reducing thermal load vs. linear regulators and often eliminating heatsinks. |
| Quiescent Current | 5.0–9.0 mA operating, 80 µA in TTL shutdown mode - critical for low-power standby states in battery-backed systems. |
| Protection Features | Integrated thermal shutdown, cycle-by-cycle current limiting, and safe ON/OFF logic interface (VIL ≤ 1.2 V, VIH ≥ 2.2 V). |
Pinout & Package
LM2575T-3.3 is supplied in TO-220 package (Case 314D, T suffix), with heatsink surface electrically connected to Pin 3 (GND). This thermally enhanced through-hole package enables direct mounting to metal chassis or heatsinks for high-power operation without additional thermal interface materials.
| 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. |
| 2 - Output | Emitter of internal NPN switch | Delivers regulated 3.3 V output; saturation voltage ≤1.2 V ensures low dropout at full load; PCB copper area must be minimized to reduce EMI coupling. |
| 3 - GND | Circuit ground reference | Common return for input, output, feedback, and ON/OFF; single-point grounding recommended to avoid ground loops in switching layout. |
| 4 - Feedback | Regulation sense node | Internally tied to fixed 3.3 V divider; not accessible externally - eliminates need for external resistors but prevents output adjustment. |
| 5 - ON/OFF | TTL-compatible enable/disable control | Pull ≥2.2 V to disable (80 µA standby); pull ≤1.2 V or ground to enable; compatible with microcontroller GPIO without level shifting. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed-output simplicity | Eliminates external feedback resistors - reduces BOM count, layout complexity, and calibration drift in production. |
| High-efficiency buck topology | 75% typical efficiency at 1.0 A avoids >2 W dissipation seen in linear regulators, enabling compact thermal design. |
| Robust protection suite | Thermal shutdown + cycle-by-cycle current limiting prevent damage during short-circuit, overload, or startup faults. |
| Standard inductor compatibility | Optimized for widely available 330 µH inductors (e.g., Renco RL1952, Pulse PE-52627), simplifying sourcing and qualification. |
| Low-standby power control | 80 µA shutdown current enables energy-sensitive applications like battery-powered IoT nodes or always-on monitoring circuits. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
|
Use Scenario: Powering isolated 3.3 V digital logic for analog-to-digital converters and CAN transceivers in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Primary 3.3 V buck regulator converting 24 V vehicle or factory bus to clean logic supply. Use Value: 75% efficiency minimizes heat buildup inside sealed enclosures; 40 V max input withstands load-dump transients up to ISO 7637-2 Pulse 5a. |
Use Scenario: Supplying 3.3 V to microcontroller, EEPROM, and LIN transceivers in door module electronics. IC Role / Device Role / Timing Role: Main system regulator with ON/OFF pin synchronized to vehicle ignition state. Use Value: 80 µA standby current extends battery life during vehicle sleep mode; thermal shutdown protects against under-hood overheating. |
| Point-of-Sale Terminal | Network Edge Router Board |
|
Use Scenario: Generating 3.3 V for ARM-based payment processor and secure element ICs from 12 V wall adapter input. IC Role / Device Role / Timing Role: Compact, cost-optimized DC/DC stage replacing inefficient linear regulator + LDO cascade. Use Value: Single TO-220 footprint replaces two ICs; 1.0 A output supports burst-mode processing without voltage droop. |
Use Scenario: Providing 3.3 V to Ethernet PHY, packet buffer memory, and management MCU on multi-layer router PCB. IC Role / Device Role / Timing Role: Local point-of-load regulator with minimal external components near noise-sensitive analog sections. Use Value: Fixed 3.3 V output ensures compliance with IEEE 802.3 voltage tolerance; 52 kHz switching avoids interference with 2.4 GHz/5 GHz RF bands. |
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 | Extended input range (4.75–60 V), higher thermal resistance (RJA = 70°C/W), same pinout and electrical specs. | Suitable for 48 V telecom or industrial systems where input may exceed 40 V; requires more careful thermal design. | Select when input voltage exceeds 40 V; verify heatsink adequacy due to higher RJA. |
| MP1584EN-LF-Z | Higher switching frequency (1.5 MHz), smaller external components, 3 A output, but requires external feedback resistors and lacks ON/OFF pin. | Better for space-constrained designs; unsuitable where TTL shutdown or fixed 3.3 V without resistor tuning is mandatory. | Choose for miniaturized boards needing <1 cm² solution size; avoid if legacy ON/OFF control or resistor-free setup is required. |
Compared with LM2575HVT-3.3, the LM2575T-3.3 offers lower thermal resistance (65°C/W) for 40 V max inputs, while MP1584EN-LF-Z trades pin compatibility and simplicity for higher frequency and current - making LM2575T-3.3 optimal for cost-sensitive, thermally stable, fixed-output industrial power rails.
Availability
LM2575T-3.3 is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and network infrastructure requiring stable component supply, long-lifecycle support, and proven reliability in harsh environments.
Supply support for LM2575T-3.3 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 supplier focused on energy-efficient power management, analog, and sensor solutions for automotive, industrial, and cloud infrastructure markets.
The LM2575 series was designed as a rugged, easy-to-use buck regulator family targeting cost-sensitive, high-reliability power conversion in industrial controls and automotive subsystems - emphasizing minimal external parts and robust fault protection.
FAQ
What is the maximum input voltage rating for LM2575T-3.3?
The absolute maximum input voltage for LM2575T-3.3 is 45 V, but the recommended operating maximum is 40 V per the datasheet's Operating Ratings. Exceeding 40 V risks violating guaranteed performance limits, especially under high-temperature conditions. For applications with transient spikes above 40 V (e.g., automotive load dump), consider the LM2575HVT-3.3 variant rated to 60 V input.
Does LM2575T-3.3 require an external feedback resistor network?
No, LM2575T-3.3 does not require external feedback resistors. It integrates an internal resistor divider optimized for 3.3 V output, unlike the LM2575-ADJ version. Pin 4 (Feedback) is internally connected and not user-accessible - simplifying design and eliminating resistor tolerance and temperature drift concerns in the regulation loop.
Can LM2575T-3.3 drive a 1.0 A load continuously without a heatsink?
Yes, LM2575T-3.3 can deliver 1.0 A continuously without a heatsink under typical conditions: ambient temperature ≤50°C, 12 V input, and adequate PCB copper area (≥2 in² on layer 1 connected to Pin 3). Thermal calculations using RJA = 65°C/W show junction rise of ~45°C - well below the 125°C max operating limit. Higher input voltages or ambient temperatures require heatsinking.
What diode is recommended for use with LM2575T-3.3?
The datasheet specifies the 1N5819 Schottky diode (30 V, 1 A) as the standard catch diode for LM2575T-3.3 in typical applications. Its low forward voltage (~0.45 V) minimizes conduction loss, and its fast recovery prevents reverse recovery spikes. For higher reliability, alternatives include MBR130LSFT1G (30 V, 3 A) or SS14 (40 V, 1 A), all in DO-41 or SMA packages.
How does the ON/OFF pin function on LM2575T-3.3?
The ON/OFF pin (Pin 5) enables TTL-level control: applying ≥2.2 V disables the regulator (reducing input current to ~80 µA), while ≤1.2 V or grounding enables normal operation. This pin is compatible with 3.3 V and 5 V logic outputs without level shifters. Internal hysteresis prevents oscillation near the threshold, and leakage current remains below 30 µA across temperature.
LM2575T-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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-3.3 FAQ
1.How can I place an order for LM2575T-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2575T-3.3 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-3.3 reliable?
The price and inventory of LM2575T-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2575T-3.3 is usually 5 days.
3.What payment methods are accepted for LM2575T-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575T-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2575T-3.3?
LM2575T-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2575T-3.3 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-3.3?
For technical support, including LM2575T-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575T-3.3 requirements.
6.How does Aetrix verify that LM2575T-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2575T-3.3 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-3.3 meets industry standards.
7.What is the process for return or replacement of LM2575T-3.3?
All LM2575T-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2575T-3.3, 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-3.3 part is unused and in its original packaging.
Return procedure for LM2575T-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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