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Texas Instruments LM2575S-3.3
- Part No.:
- LM2575S-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2575S-3.3.pdf
- Description:
- IC REG BUCK 3.3V 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,030
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Product details
Overview
LM2575S-3.3 from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator in a 5-lead surface-mount TO-263 package, delivering a fixed 3.3V output with ±4% tolerance across 4.75–40V input and 0.2–1A load. It integrates a 52 kHz oscillator, cycle-by-cycle current limiting, thermal shutdown, and TTL-compatible shutdown control-designed for compact, high-efficiency DC/DC conversion in industrial power rails and embedded system supplies.
For engineers reviewing the LM2575S-3.3 datasheet, LM2575S-3.3 pinout, LM2575S-3.3 application, or LM2575S-3.3 equivalent, key selection considerations include its 3.3V fixed output, 1A continuous output current capability, 52 kHz fixed-frequency operation, TO-263 thermal performance (θJA = 37°C/W with ≥1 in² copper), and compatibility with standard off-the-shelf inductors and Schottky catch diodes.
Technical Context
The LM2575S-3.3 implements a classic buck topology with an internal NPN power switch, fixed-frequency PWM control, and built-in frequency compensation-requiring only four external components: input capacitor, output capacitor, inductor, and catch diode. Its feedback loop references a precise 1.23V internal bandgap, enabling stable regulation without external resistive dividers.
Operation includes cycle-by-cycle peak current limiting (typ. 2.2A), thermal shutdown at ~150°C junction temperature, and TTL-level shutdown with 50 μA standby current. The device maintains ±4% output voltage accuracy over full operating temperature (−40°C to +125°C) and line/load conditions, with no minimum load requirement.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±4% over 4.75–40V input and 0.2–1A load-enables direct replacement of linear regulators without feedback resistor network. |
| Output Current | 1A continuous-supports mid-power applications such as microcontroller core supplies and FPGA I/O rails without external current boosting. |
| Switching Frequency | 52 kHz fixed-allows use of low-cost, high-saturation-current inductors and simplifies EMI filtering compared to MHz-range converters. |
| Efficiency | 75% at VIN = 12V, IOUT = 1A-reduces heat sink requirements and improves thermal margin in sealed enclosures. |
| Thermal Resistance | θJA = 37°C/W (with ≥1 in² PCB copper)-enables 1A operation at ambient up to +85°C without forced air or external heatsink. |
| Shutdown Current | 50 μA typical-supports low-power sleep modes in battery-backed or energy-conscious systems. |
| Input Voltage Range | 4.75V to 40V-covers wide-input industrial, automotive (cold-crank tolerant), and telecom supply ranges. |
Pinout & Package
LM2575S-3.3 uses a 5-lead surface-mount TO-263 (DDPAK) package with exposed thermal pad. Pin 1 is Input, Pin 2 is Output, Pin 3 is Ground, Pin 4 is Feedback (internally tied to 3.3V output), and Pin 5 is ON/OFF (TTL-compatible enable).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input voltage supply | Accepts 4.75–40V DC; requires local 100 μF aluminum electrolytic bypass capacitor. |
| 2 (OUT) | Regulated output node | Delivers 3.3V @ up to 1A; connects to inductor and output capacitor; drives load directly. |
| 3 (GND) | Power and signal ground reference | Common return for input, output, feedback, and shutdown paths; must be low-inductance connection to thermal pad. |
| 4 (FEEDBACK) | Internal voltage sense point | Internally connected to 3.3V output; not user-accessible-no external resistor divider required. |
| 5 (ON/OFF) | TTL-compatible enable/disable control | Logic-high (>2.2V) enables regulation; logic-low (<0.8V) disables output and reduces quiescent current to 50 μA. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1A NPN switch | Eliminates need for external MOSFET or transistor-reduces BOM count and layout complexity. |
| Fixed 52 kHz oscillator | Enables predictable EMI profile and simplifies filter design using standard inductors (e.g., Pulse PE-52627 for 3.3V output). |
| Thermal shutdown + current limit | Provides autonomous fault protection under overload, short-circuit, or inadequate heatsinking-no external monitoring circuitry needed. |
| TTL shutdown interface | Allows seamless integration with microcontroller GPIO or system power sequencers for controlled power-up/down sequencing. |
| TO-263 thermal performance | 37°C/W θJA with 1 in² copper enables full 1A output at +85°C ambient-superior to TO-220 in space-constrained PCBs. |
Applications
| Industrial PLC I/O Power | Embedded Microcontroller Core Supply |
|---|---|
|
Use Scenario: Providing clean, regulated 3.3V power to digital I/O modules in programmable logic controllers operating from 24V DC field buses. IC Role / Device Role / Timing Role: Primary buck converter generating isolated 3.3V rail for logic-level translation, optocoupler drivers, and ADC reference. Use Value: Delivers 1A at 75% efficiency with no heatsink required-reducing thermal stress and enabling conformal coating in harsh environments. |
Use Scenario: Supplying core voltage to ARM Cortex-M4 microcontrollers in edge sensor nodes powered by 12V wall adapters or PoE injectors. IC Role / Device Role / Timing Role: Main DC/DC regulator converting unregulated input to stable 3.3V for CPU, RAM, and peripheral interfaces. Use Value: Fixed-output architecture eliminates feedback resistor placement errors; 50 μA shutdown current extends battery life during deep sleep modes. |
| On-Card Buck Pre-Regulator | Positive-to-Negative Converter (Buck-Boost) |
|
Use Scenario: Generating intermediate 3.3V rail from higher-voltage system bus (e.g., 12V or 24V) to feed low-noise LDOs for analog subsystems. IC Role / Device Role / Timing Role: High-efficiency pre-regulator reducing dropout and heat dissipation before final LDO stage. Use Value: 75% efficiency at 1A minimizes power loss upstream-preserving headroom for downstream LDOs and improving overall system thermal budget. |
Use Scenario: Configured in inverting buck-boost topology to generate −3.3V from +12V for op-amp biasing in instrumentation front-ends. IC Role / Device Role / Timing Role: Switching controller repurposed as inverting regulator via modified external component arrangement. Use Value: Leverages same 52 kHz frequency and current-limit protection-enabling dual-rail generation without adding dedicated inverting IC. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2575T-3.3 | TO-220 through-hole package; θJA = 45°C/W (with 4 in² copper); same electrical specs. | Preferred for prototyping, manual assembly, or legacy through-hole designs requiring mechanical robustness. | Select when board assembly process favors through-hole components or thermal management relies on external heatsinks. |
| LM2596S-3.3 | Higher 150 kHz switching frequency; 3A output rating; adjustable version only-fixed 3.3V variant requires external feedback. | Better suited for space-constrained designs needing higher current or lower output ripple due to faster switching. | Choose when >1A load or <1% output ripple is required; verify feedback network compatibility and inductor availability. |
Compared with LM2575T-3.3, the LM2575S-3.3 offers superior thermal performance in surface-mount layouts; compared with LM2596S-3.3, it trades higher current and frequency for simpler implementation, proven reliability, and guaranteed fixed-output accuracy without external resistors.
Availability
LM2575S-3.3 is available at Aetrix Electronics and suitable for industrial PLC I/O power, embedded microcontroller core supplies, and on-card buck pre-regulators requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2575S-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
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 drop-in, high-efficiency replacement for linear regulators in industrial, automotive, and telecom power supplies-emphasizing simplicity, thermal resilience, and minimal external component count.
FAQ
What is the maximum input voltage for the LM2575S-3.3?
The LM2575S-3.3 supports a maximum input voltage of 40V under normal operating conditions. This rating applies across the full temperature range (−40°C to +125°C). Exceeding 40V may trigger internal protection or cause permanent damage. For higher input applications, the LM2575HV-S-3.3 variant supports up to 60V input.
Does the LM2575S-3.3 require external feedback resistors?
No, the LM2575S-3.3 does not require external feedback resistors. It is a fixed-output variant with internal feedback circuitry configured for 3.3V regulation. Pin 4 (FEEDBACK) is internally connected to the output and is not accessible for external adjustment-eliminating resistor tolerance errors and layout sensitivity.
What package type is used by the LM2575S-3.3?
The LM2575S-3.3 uses a 5-lead surface-mount TO-263 (also known as DDPAK) package with an exposed thermal pad. This package provides significantly better thermal performance (θJA = 37°C/W with ≥1 in² PCB copper) than the through-hole TO-220 variant, making it ideal for compact, high-density PCB layouts.
Can the LM2575S-3.3 be used in a negative-output configuration?
Yes, the LM2575S-3.3 can be configured as a positive-to-negative inverting buck-boost converter per TI Application Note SLVA001. In this topology, the device generates −3.3V from a +12V input using modified external components-including reversed catch diode and repositioned inductor-while retaining its internal current limiting and thermal protection.
What is the typical efficiency of the LM2575S-3.3 at full load?
The LM2575S-3.3 achieves 75% typical efficiency at VIN = 12V and IOUT = 1A. Efficiency varies with input voltage and load: it rises to ~88% at higher input-to-output ratios (e.g., 12V→3.3V) and drops slightly at lower input voltages near the dropout threshold (4.75V). Full-load efficiency is measured with recommended external components per Figure 25 of the datasheet.
LM2575S-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tube
- 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 (DDPAK-5)
LM2575S-3.3 FAQ
1.How can I place an order for LM2575S-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2575S-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 LM2575S-3.3 reliable?
The price and inventory of LM2575S-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 LM2575S-3.3 is usually 5 days.
3.What payment methods are accepted for LM2575S-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575S-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2575S-3.3?
LM2575S-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2575S-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 LM2575S-3.3?
For technical support, including LM2575S-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575S-3.3 requirements.
6.How does Aetrix verify that LM2575S-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2575S-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 LM2575S-3.3 meets industry standards.
7.What is the process for return or replacement of LM2575S-3.3?
All LM2575S-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2575S-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 LM2575S-3.3 part is unused and in its original packaging.
Return procedure for LM2575S-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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