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Texas Instruments LM2596SX-3.3
- Part No.:
- LM2596SX-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2596SX-3.3.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:3,696
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Product details
Overview
LM2596SX-3.3 from Texas Instruments is a nonsynchronous step-down DC-DC converter IC delivering 3.3 V at up to 3 A output current, operating at a fixed 150-kHz switching frequency with input voltage support up to 40 V. It integrates internal frequency compensation and thermal/current protection, and is used in embedded power supplies requiring stable, low-cost buck regulation.
For engineers reviewing the LM2596SX-3.3 datasheet, LM2596SX-3.3 pinout, LM2596SX-3.3 application, or LM2596SX-3.3 equivalent, key selection criteria include output voltage tolerance (±4%), standby quiescent current (80 µA), ON/OFF logic threshold (1.3 V), thermal shutdown behavior, and compatibility with standard off-the-shelf inductors.
Technical Context
The LM2596SX-3.3 implements a fixed-frequency, pulse-width modulation (PWM) buck topology with an integrated NPN switch and internal oscillator. Its control loop uses voltage-mode feedback referenced to a 1.23-V internal bandgap, with the output voltage set by internal resistor dividers for the 3.3-V fixed version.
It operates in continuous conduction mode (CCM) under typical loads ≥0.2 A, supports TTL-compatible shutdown via the ON/OFF pin, and features two-stage current limiting-peak current limit (~4.5 A) followed by frequency foldback under overload-to maintain safe operation without external sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3 V ±4% over line, load, and temperature (–40°C to +125°C) |
| Max Output Current | 3 A DC continuous; limited by thermal design and package RθJA |
| Input Voltage Range | 4.5 V to 40 V; absolute max 45 V |
| Switching Frequency | 150 kHz ±15%; enables use of compact, low-cost filter inductors |
| Quiescent Current | 80 µA in shutdown (ON/OFF pin >1.3 V); 5–10 mA in active operation |
| Feedback Reference | 1.23 V internal reference; not accessible externally on fixed-output variants |
| Thermal Protection | Internal junction temperature shutdown at 150°C; automatic recovery on cooldown |
Pinout & Package
LM2596SX-3.3 is supplied in a 5-pin TO-263 (KTT) surface-mount package with exposed thermal pad. The package measures 10.10 mm × 8.89 mm and is rated for 30°C/W (with 2.5 in² copper) to 20°C/W (with 3 in² double-sided copper) junction-to-ambient thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Positive input supply | Accepts 4.5–40 V; requires local 100-µF low-ESR input capacitor to handle high di/dt switching currents |
| 2 - OUTPUT | Switch node | Drives external catch diode and inductor; voltage swings between ~VIN–1.4 V and –0.5 V; minimal PCB copper area required |
| 3 - GND | Power ground | Common return for input capacitor, output capacitor, and feedback network; must be low-impedance connection to thermal pad |
| 4 - FEEDBACK | Regulation sense | Internally connected to 3.3-V divider; not user-accessible on fixed-output variant; unused pin tied to GND |
| 5 - ON/OFF | Shutdown control | TTL-compatible enable: <1.3 V = ON; >1.3 V = OFF; draws ≤15 µA when asserted high |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3-V output | Eliminates external resistor divider; reduces BOM count and layout sensitivity vs. adjustable versions |
| 150-kHz fixed oscillator | Enables use of standard, low-cost 33–100 µH shielded inductors without custom magnetics |
| TTL shutdown capability | Allows system-level power sequencing and low-power sleep modes with microcontroller GPIO |
| Integrated thermal shutdown | Prevents damage during sustained overload or poor heatsinking; no external circuitry needed |
| Two-stage current limiting | First stage limits peak switch current (~4.5 A); second stage reduces frequency to limit average power under fault |
Applications
| Industrial PLC I/O Modules | Home Theater Power Rails |
|---|---|
Use Scenario: Providing isolated 3.3-V logic supply for digital I/O buffers and communication interfaces in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator converting 24-V DC bus to clean 3.3-V rail for FPGA configuration, RS-485 transceivers, and ADC reference. Use Value: Delivers 3 A with <±4% output tolerance across –40°C to +85°C ambient, supporting wide industrial temperature operation without derating. | Use Scenario: Generating stable 3.3-V supply for HDMI controller ICs, audio DSPs, and memory in AV receivers and soundbars. IC Role / Device Role / Timing Role: Secondary buck converter downstream of a 12-V main rail, powering low-noise digital subsystems with tight ripple requirements. Use Value: Achieves 73% efficiency at 12-V input/3-A load, minimizing heat buildup in thermally constrained chassis while maintaining <100-mVpp output ripple with standard ceramic capacitors. |
| Appliance Control Boards | Grid Infrastructure Meters |
Use Scenario: Powering MCU, touch controller, and display driver on smart appliance mainboards operating from rectified AC or 12-V battery backup. IC Role / Device Role / Timing Role: Main 3.3-V point-of-load regulator with ON/OFF control synchronized to system wake/sleep cycles. Use Value: Enables <80-µA standby current during deep-sleep mode, extending battery life in cordless or backup-powered appliances. | Use Scenario: Supplying 3.3-V logic rail for metrology SoCs and RF modules in smart electricity meters exposed to outdoor temperature extremes. IC Role / Device Role / Timing Role: Robust primary regulator handling wide-input transients (e.g., 40-V surges) and maintaining regulation during brownouts. Use Value: Withstands 45-V absolute maximum input and includes built-in overtemperature and cycle-by-cycle current limiting for field reliability in unventilated enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596T-3.3 | TO-220 through-hole package; higher RθJA (50°C/W vs. 30°C/W); identical electrical specs | Suitable for prototyping or low-volume assemblies where manual soldering is preferred | Select LM2596T-3.3 only if board assembly process does not support SMT or thermal pad reflow is unavailable |
| LMR51430RGER | Synchronous buck; 4.5–36-V input; 3-A; 500-kHz/1.1-MHz selectable; higher efficiency (92% typical) | Requires external compensation; smaller solution size but more complex layout and BOM | Choose LMR51430RGER for new designs prioritizing efficiency, size, or EMI performance over cost and simplicity |
Compared with LM2596SX-3.3, the TO-220-based LM2596T-3.3 offers identical regulation performance but requires larger heatsinking due to higher thermal resistance, while the LMR51430RGER delivers superior efficiency and integration at the cost of increased design complexity and loss of drop-in compatibility.
Availability
LM2596SX-3.3 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, home theater power rails, and appliance control boards requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LM2596SX-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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies.
The LM2596 series belongs to TI's SIMPLE SWITCHER® power converter family, designed specifically for cost-sensitive, medium-power DC-DC applications where ease of use, minimal external components, and robust protection are prioritized over ultra-high efficiency or ultra-small footprint.
FAQ
What is the maximum input voltage rating for the LM2596SX-3.3?
The LM2596SX-3.3 has an absolute maximum input voltage rating of 45 V, but its recommended operating range is 4.5 V to 40 V. Operation above 40 V may trigger internal protection or reduce reliability. The device includes overvoltage clamp structures on the VIN pin, and exceeding 45 V risks permanent damage per the Absolute Maximum Ratings table in the official datasheet SNVS124G.
Does the LM2596SX-3.3 require an external feedback resistor network?
No, the LM2596SX-3.3 does not require an external feedback resistor network. As a fixed-output variant, it contains internal precision resistors that set the regulated output to 3.3 V ±4%. Pin 4 (FEEDBACK) is internally connected and must be left unconnected or tied to ground; adding external components to this pin will disrupt regulation and is not supported.
How does the ON/OFF pin function on the LM2596SX-3.3?
The ON/OFF pin (Pin 5) of the LM2596SX-3.3 provides TTL-compatible shutdown control: pulling it below ~1.3 V (at 25°C) enables regulation, while pulling it above ~1.3 V disables switching and reduces total input current to ~80 µA. The pin accepts voltages up to 25 V and draws ≤15 µA when asserted high, enabling direct interfacing with microcontrollers or logic gates without level-shifting circuitry.
What thermal considerations apply to the LM2596SX-3.3 in TO-263 package?
The LM2596SX-3.3 in TO-263 (KTT) package requires proper thermal pad soldering to a minimum 2.5 in² copper area for rated 3-A operation. With 2.5 in² of 1-oz copper, its junction-to-ambient thermal resistance is 30°C/W; with 3 in² double-sided copper, it drops to 20°C/W. Without adequate copper, junction temperature can exceed 150°C under full load, triggering thermal shutdown. Thermal vias under the pad are strongly recommended.
Can the LM2596SX-3.3 be used in an inverting (buck-boost) configuration?
Yes, the LM2596SX-3.3 can be configured as an inverting regulator to generate negative output voltages, such as –3.3 V, using the topology shown in Figure 8-5 of the datasheet. This requires bootstrapping the GND pin to the negative output and grounding the FEEDBACK pin. However, startup current demands increase significantly, and the ON/OFF threshold shifts to ~13 V; additional diodes (D1, D3) and careful capacitor selection are mandatory for stability and surge protection.
LM2596SX-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:
- Not For New Designs
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
LM2596SX-3.3 FAQ
1.How can I place an order for LM2596SX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2596SX-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 LM2596SX-3.3 reliable?
The price and inventory of LM2596SX-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 LM2596SX-3.3 is usually 5 days.
3.What payment methods are accepted for LM2596SX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2596SX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2596SX-3.3?
LM2596SX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2596SX-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 LM2596SX-3.3?
For technical support, including LM2596SX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2596SX-3.3 requirements.
6.How does Aetrix verify that LM2596SX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2596SX-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 LM2596SX-3.3 meets industry standards.
7.What is the process for return or replacement of LM2596SX-3.3?
All LM2596SX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2596SX-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 LM2596SX-3.3 part is unused and in its original packaging.
Return procedure for LM2596SX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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