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Texas Instruments LM2575SX-3.3
- Part No.:
- LM2575SX-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2575SX-3.3.pdf
- Description:
- IC REG BUCK 3.3V 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:4,276
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Product details
Overview
LM2575SX-3.3 from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator with fixed 3.3V output, 52 kHz internal oscillator, ±4% output voltage tolerance over line/load/temperature, 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 from 4.75–40V input.
For engineers reviewing the LM2575SX-3.3 datasheet, LM2575SX-3.3 pinout, LM2575SX-3.3 application, or LM2575SX-3.3 equivalent, key selection factors include its TO-263 (DDPAK) package thermal performance (θJA = 37°C/W with 1 in² copper), 0.9V switch saturation voltage at 1A, and TTL-compatible shutdown with 50 μA standby current.
Technical Context
The LM2575SX-3.3 implements a fixed-frequency pulse-width modulation (PWM) buck topology with internal 52 kHz oscillator and built-in N-channel MOSFET switch. Its feedback loop uses a precision 1.23V reference and external resistor divider (not required for fixed-output versions) to regulate output voltage.
It features cycle-by-cycle current limiting (2.2A peak), thermal shutdown at 150°C junction temperature, and TTL-level ON/OFF control with 1.4V logic-high threshold. Input voltage range is 4.75V to 40V, supporting wide-input industrial and embedded systems without external pre-regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±4% over 4.75–40V input and 0.2–1A load - ensures stable logic supply for 3.3V microcontrollers and FPGAs. |
| Max Output Current | 1A continuous - supports single-rail digital subsystems without external current boosting. |
| Oscillator Frequency | 52 kHz (±10%) - enables use of low-cost, high-saturation-current off-the-shelf inductors (e.g., 100 µH for 3.3V output). |
| Switch Saturation Voltage | 0.9V at 1A - reduces conduction loss and improves efficiency vs. higher-VDS(on) alternatives. |
| Standby Current | 50 µA typical with TTL shutdown - enables low-power sleep modes in battery-backed or energy-conscious designs. |
| Thermal Resistance | θJA = 37°C/W (with 1 in² PCB copper) - allows full 1A operation at +85°C ambient without heatsink. |
| Input Voltage Range | 4.75V to 40V - accommodates 12V/24V industrial rails, automotive cold-crank transients, and unregulated wall adapters. |
Pinout & Package
LM2575SX-3.3 is housed in a 5-lead DDPAK/TO-263 surface-mount package (package code KTT0005B), featuring an exposed thermal pad for enhanced heat dissipation. The package is RoHS-compliant and designed for reflow soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Input | Unregulated DC input supply | Accepts 4.75–40V; requires local 100 µF/75V aluminum electrolytic bypass capacitor. |
| 2 - Ground | Power and signal reference | Must be connected to thermal pad and low-impedance ground plane to ensure thermal and EMI performance. |
| 3 - Output | Regulated 3.3V switching node | Drives external catch diode and output filter; connects to 330 µF/25V bulk capacitor. |
| 4 - Feedback | Output voltage sensing | Internally tied to 3.3V divider; not accessible on fixed-output variants - no external resistor needed. |
| 5 - ON/OFF | TTL-compatible enable control | Logic-low (≤1.2V) disables regulator; draws ≤10 µA in shutdown - supports system-level power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated thermal shutdown | Activates at 150°C junction temperature and auto-recovers - eliminates need for external thermal protection circuitry. |
| Cycle-by-cycle current limit | 2.2A peak switch current - prevents damage during output overload or short-circuit without latch-up. |
| Fixed 52 kHz oscillator | Enables predictable EMI filtering and eliminates external timing components - simplifies layout and BOM. |
| Low quiescent current | 5 mA operating / 50 µA standby - extends runtime in always-on or intermittent-duty applications. |
| Wide input voltage range | 4.75V to 40V - supports direct connection to 12V/24V systems, including automotive and industrial power buses. |
Applications
| Industrial PLC I/O Module Power | Embedded Controller Core Supply |
|---|---|
|
Use Scenario: Provides clean 3.3V rail for ARM Cortex-M microcontrollers and isolated CAN transceivers in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Primary buck regulator converting 24V field bus to logic-level supply; operates continuously under 40°C ambient with no heatsink. Use Value: Eliminates linear regulator heat sink, reduces board area by >60%, and maintains ±4% regulation across 0.2–1A load steps. |
Use Scenario: Powers FPGA configuration memory and I/O banks in edge-computing gateways with variable load profiles. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter with TTL shutdown synchronized to host processor sleep states. Use Value: Achieves 75% efficiency at 1A/12VIN, cuts standby power to 50 µA, and meets EN55022 Class B conducted EMI with standard LC filter. |
| Medical Sensor Node Power | Test Equipment Auxiliary Rail |
|
Use Scenario: Supplies 3.3V to low-noise analog front-ends and BLE radios in portable diagnostic devices powered by Li-ion batteries. IC Role / Device Role / Timing Role: Main DC-DC stage stepping down 7.4V battery pack to regulated logic rail; enabled only during active measurement cycles. Use Value: Delivers 1A peak current for radio transmission bursts while maintaining <10 mVpp output ripple and <50 µA shutdown current. |
Use Scenario: Generates stable 3.3V auxiliary supply for digital control logic in benchtop power analyzers and signal generators. IC Role / Device Role / Timing Role: Pre-regulator feeding low-dropout linear stages; rejects input ripple from noisy 12V SMPS primary supply. Use Value: Provides ±0.13V output tolerance (3.3V ±4%) across 4.75–40V input range, enabling robust operation despite upstream supply variation. |
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 = 65°C/W (no heatsink); same electrical specs. | Preferred for prototyping, manual assembly, or legacy through-hole designs. | Select when mechanical mounting constraints favor vertical leaded packages or when thermal budget permits larger heatsink. |
| LM2596SX-3.3 | Higher 150 kHz switching frequency; 3A output rating; improved efficiency (up to 88% at 1A); different pinout. | Suitable for space-constrained designs needing higher current or lower output ripple. | Choose when upgrading for higher efficiency or future-proofing for load growth - requires PCB redesign due to non-pin-compatible layout. |
Compared with LM2575T-3.3, the LM2575SX-3.3 offers superior thermal performance in surface-mount layouts; compared with LM2596SX-3.3, it trades higher frequency and current capability for proven reliability, simpler EMI filtering, and direct drop-in replacement in existing LM2575-based designs.
Availability
LM2575SX-3.3 is available at Aetrix Electronics and suitable for industrial automation, embedded controller power, and medical sensor node applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2575SX-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 and embedded processing technologies, with decades of expertise in power management ICs for industrial, automotive, and consumer markets.
The LM2575 series was designed as a SIMPLE SWITCHER® solution to replace inefficient linear regulators in cost-sensitive, thermally constrained applications - emphasizing ease of use, minimal external components, and robust fault protection.
FAQ
What is the maximum input voltage rating for LM2575SX-3.3?
The LM2575SX-3.3 has an absolute maximum input voltage of 45V and a recommended operating input voltage range of 4.75V to 40V. Exceeding 40V may degrade long-term reliability or trigger overvoltage protection in some conditions, though the device remains functional up to 45V per absolute ratings. Always maintain ≥1V margin below 45V in production designs.
Does LM2575SX-3.3 require external feedback resistors?
No. The LM2575SX-3.3 is a fixed-output variant with internal resistor divider network set for 3.3V regulation. Pin 4 (Feedback) is internally connected and not accessible externally - no external resistors are needed, unlike the adjustable LM2575-ADJ version.
What is the thermal performance of LM2575SX-3.3 on a standard PCB?
With 1 square inch of 2-oz copper connected to the exposed thermal pad, the LM2575SX-3.3 achieves θJA = 37°C/W. This allows full 1A continuous output at +85°C ambient temperature without a heatsink. Performance degrades to θJA = 50°C/W with only 0.5 in² copper, limiting usable current at elevated temperatures.
Can LM2575SX-3.3 be used in automotive applications?
Yes - the LM2575SX-3.3 operates across −40°C to +125°C junction temperature and supports input transients up to 40V, making it suitable for 12V automotive subsystems (e.g., body control modules, infotainment peripherals). However, it is not AEC-Q100 qualified; for safety-critical applications, consult TI's automotive-grade alternatives.
What type of catch diode is recommended for LM2575SX-3.3?
A Schottky diode rated for ≥1.2× output current (≥1.2A) and ≥1.25× max input voltage (≥50V) is recommended. Common choices include SR103 (30V, 1A), MBR130 (30V, 1A), or 11DQ06 (60V, 1A). Fast-recovery diodes like UF4007 may be used but reduce efficiency due to higher forward voltage and reverse recovery losses.
LM2575SX-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:
- 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 (DDPAK-5)
LM2575SX-3.3 FAQ
1.How can I place an order for LM2575SX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2575SX-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 LM2575SX-3.3 reliable?
The price and inventory of LM2575SX-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 LM2575SX-3.3 is usually 5 days.
3.What payment methods are accepted for LM2575SX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575SX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2575SX-3.3?
LM2575SX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2575SX-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 LM2575SX-3.3?
For technical support, including LM2575SX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575SX-3.3 requirements.
6.How does Aetrix verify that LM2575SX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2575SX-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 LM2575SX-3.3 meets industry standards.
7.What is the process for return or replacement of LM2575SX-3.3?
All LM2575SX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2575SX-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 LM2575SX-3.3 part is unused and in its original packaging.
Return procedure for LM2575SX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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