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Texas Instruments LM2575SX-3.3/NOPB
- Part No.:
- LM2575SX-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2575SX-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:450
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Product details
Overview
LM2575SX-3.3/NOPB from Texas Instruments is a monolithic 1A step-down (buck) switching voltage regulator in TO-263 (DDPAK) 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 pre-regulation.
For engineers reviewing the LM2575SX-3.3/NOPB datasheet, LM2575SX-3.3/NOPB pinout, LM2575SX-3.3/NOPB application, or LM2575SX-3.3/NOPB equivalent, key selection considerations include its 3.3V fixed output, 1A continuous output current, 40V max input, 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 LM2575SX-3.3/NOPB implements a fixed-frequency (52 kHz) pulse-width modulation (PWM) buck topology with internal NPN switch, feedback comparator, and oscillator. Regulation is achieved via voltage-mode control using an internal 1.23V reference and resistive feedback network (not required for fixed-output variants).
It features built-in protection including thermal shutdown at ~150°C junction temperature, cycle-by-cycle peak current limiting (1.7–3.2A), and 50 μA typical standby current during TTL-level shutdown-enabling robust operation under overload, short-circuit, and transient conditions without external sensing circuitry.
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 power for mid-power digital subsystems without external current boosting. |
| Input Voltage Range | 4.75V to 40V - accommodates wide-input industrial, automotive, and telecom front-end supplies. |
| Switching Frequency | 52 kHz fixed - enables use of low-cost, high-saturation-current inductors and simplifies EMI filtering vs. higher-frequency alternatives. |
| Efficiency | 75% at 12VIN/3.3VOUT/1A - reduces heat generation versus linear regulators, minimizing or eliminating need for heatsinks. |
| Thermal Resistance | θJA = 37°C/W (with 1 in² PCB copper) - enables high-power operation in space-constrained layouts with passive cooling only. |
| Shutdown Current | 50 μA typical - supports low-power sleep modes in battery-backed or energy-sensitive systems. |
Pinout & Package
LM2575SX-3.3/NOPB uses a 5-pin DDPAK/TO-263 surface-mount package with exposed thermal pad (Package Number KTT0005B). The case serves as the ground terminal and must be soldered to ≥1 in² of PCB copper for rated thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Input | Unregulated DC input supply | Accepts 4.75–40V; requires local 100 μF aluminum electrolytic bypass capacitor. |
| 2 - Ground | Power and signal reference | Common return for input, output, feedback, and shutdown; electrically tied to exposed thermal pad. |
| 3 - Output | Regulated 3.3V switching node | Drives external inductor and catch diode; connects to 330 μF output capacitor and load. |
| 4 - Feedback | Voltage sense input | Internally connected to 3.3V divider; left unconnected for fixed-output operation. |
| 5 - ON/OFF | TTL-compatible enable 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 power transistor and drive circuitry - reduces BOM count and layout complexity. |
| Internal frequency compensation | Enables stable loop response with only 4 external components - no external compensation network required. |
| Thermal shutdown + current limit | Provides autonomous fault recovery under sustained overload or short-circuit - prevents device destruction without system-level intervention. |
| Standard inductor compatibility | Optimized for widely available off-the-shelf 330 μH inductors (e.g., Pulse PE-52627) - accelerates design and procurement. |
| TTL shutdown interface | Allows direct connection to microcontroller GPIO pins without level-shifting - simplifies power sequencing and low-power mode control. |
Applications
| Industrial PLC I/O Power | Embedded System Pre-Regulator |
|---|---|
Use Scenario: Powering isolated 3.3V digital I/O modules in programmable logic controllers operating from 24V DC bus. IC Role / Device Role / Timing Role: Primary buck converter generating clean, regulated 3.3V rail for microcontroller, optocouplers, and level translators. Use Value: Delivers 1A at 75% efficiency with minimal thermal rise on standard FR4 PCB - eliminates need for heatsink in DIN-rail mounted enclosures. | Use Scenario: Generating 3.3V intermediate supply for ARM Cortex-M based edge sensor nodes powered by 12V PoE or battery packs. IC Role / Device Role / Timing Role: High-efficiency pre-regulator stepping down to 3.3V before low-noise LDO post-regulation for analog sensors and RF transceivers. Use Value: Reduces total power dissipation by >60% versus linear solution - extends battery life and lowers system thermal load in sealed housings. |
| On-Card DC/DC Conversion | Positive-to-Negative Buck-Boost |
Use Scenario: Local 3.3V supply generation directly on FPGA carrier boards with limited board area and no dedicated power module footprint. IC Role / Device Role / Timing Role: Compact, self-contained buck regulator replacing discrete switcher designs - integrated control and power switch in single TO-263 package. Use Value: Achieves full 1A capability in <1.5 cm² PCB area with standard passive components - enables dense, cost-optimized board layouts. | Use Scenario: Generating –3.3V bias rail for op-amp interfaces or RS-232 transceivers from existing +12V system supply. IC Role / Device Role / Timing Role: Configured in inverting buck-boost topology using same external components as buck mode - leverages identical IC for dual-polarity outputs. Use Value: Reuses proven LM2575SX-3.3/NOPB design assets and bill-of-materials - cuts development time and qualification effort for auxiliary negative rails. |
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); no exposed thermal pad | Suitable for prototyping, low-volume assembly, or legacy through-hole designs - less thermally efficient in high-density SMT layouts | Select when manual assembly, socketing, or mechanical mounting constraints favor through-hole form factor |
| LM2596S-3.3 | Higher 3A output current; 150 kHz switching frequency; requires different inductor/capacitor values | Better suited for higher-power loads or space-constrained designs needing smaller magnetics - not drop-in compatible due to differing frequency and compensation | Choose when >1A output or smaller passive component size is required - redesign of LC network and layout necessary |
Compared with LM2575T-3.3, the LM2575SX-3.3/NOPB offers superior thermal performance in SMT production environments; compared with LM2596S-3.3, it trades higher current capability for proven 52 kHz stability, lower EMI, and simpler magnetics selection - making it optimal for cost-sensitive, thermally constrained 1A applications.
Availability
LM2575SX-3.3/NOPB is available at Aetrix Electronics and suitable for industrial automation power supplies, embedded computing pre-regulators, and on-card DC/DC conversion requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2575SX-3.3/NOPB 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 highly reliable, production-ready power ICs.
The LM2575 series was designed as a simple, robust replacement for three-terminal linear regulators - targeting cost-sensitive, thermally constrained industrial and embedded applications where efficiency, minimal external components, and ruggedness are critical.
FAQ
What is the maximum input voltage rating for LM2575SX-3.3/NOPB?
The LM2575SX-3.3/NOPB has a maximum input voltage rating of 40V. This is specified for the standard LM2575 variant (not the HV version). Operation above 40V risks permanent damage. For 60V input applications, the LM2575HVS-3.3/NOPB must be used instead. Always observe derating guidelines per ambient temperature and PCB copper area to maintain reliability.
Does LM2575SX-3.3/NOPB require external compensation components?
No, the LM2575SX-3.3/NOPB does not require external compensation components. It integrates internal frequency compensation optimized for stable operation with just four external parts: input capacitor, output capacitor, inductor, and catch diode. This eliminates tuning complexity and ensures consistent performance across manufacturing lots and operating conditions.
Can LM2575SX-3.3/NOPB be used in a negative-output (inverting) configuration?
Yes, the LM2575SX-3.3/NOPB can be configured as a positive-to-negative buck-boost converter to generate –3.3V from a positive input. TI Application Note SLVA017 provides the validated schematic, component selection rules, and layout guidance. The same IC, inductor, diode, and capacitors are reused - only the connection topology changes from buck to inverting.
What is the thermal resistance (θJA) of LM2575SX-3.3/NOPB under standard PCB conditions?
The LM2575SX-3.3/NOPB has a junction-to-ambient thermal resistance (θJA) of 37°C/W when mounted on a PCB with 1 square inch of copper area thermally connected to its exposed DDPAK pad. With less copper (e.g., 0.5 in²), θJA rises to 50°C/W. These values assume no external heatsink - sufficient for 1A operation at moderate ambient temperatures.
Is LM2575SX-3.3/NOPB RoHS compliant and lead-free?
Yes, LM2575SX-3.3/NOPB is RoHS compliant and lead-free. The "/NOPB" suffix explicitly denotes "No Lead (Pb)-Free" packaging per TI's product nomenclature. It meets JEDEC J-STD-020 moisture sensitivity level (MSL) 3 requirements and is qualified for reflow soldering per IPC/JEDEC J-STD-020 standards.
LM2575SX-3.3/NOPB 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:
- Active
- 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/NOPB FAQ
1.How can I place an order for LM2575SX-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2575SX-3.3/NOPB 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/NOPB reliable?
The price and inventory of LM2575SX-3.3/NOPB 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/NOPB is usually 5 days.
3.What payment methods are accepted for LM2575SX-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575SX-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2575SX-3.3/NOPB?
LM2575SX-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2575SX-3.3/NOPB 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/NOPB?
For technical support, including LM2575SX-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575SX-3.3/NOPB requirements.
6.How does Aetrix verify that LM2575SX-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2575SX-3.3/NOPB 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/NOPB meets industry standards.
7.What is the process for return or replacement of LM2575SX-3.3/NOPB?
All LM2575SX-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2575SX-3.3/NOPB, 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/NOPB part is unused and in its original packaging.
Return procedure for LM2575SX-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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