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Texas Instruments LM2596T-3.3/LF03
- Part No.:
- LM2596T-3.3/LF03
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LM2596T-3.3/LF03.pdf
- Description:
- IC REG BUCK 3.3V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,186
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Product details
Overview
LM2596T-3.3/LF03 from Texas Instruments is a monolithic 3-A nonsynchronous buck DC-DC converter with fixed 3.3-V output, 150-kHz fixed-frequency operation, input voltage range up to 40 V, and integrated thermal shutdown and current-limit protection. It delivers stable regulated power in industrial power supplies and embedded systems requiring high-efficiency step-down conversion.
For engineers reviewing the LM2596T-3.3/LF03 datasheet, LM2596T-3.3/LF03 pinout, LM2596T-3.3/LF03 application, or LM2596T-3.3/LF03 equivalent, key selection criteria include output accuracy (±4% over line/load), standby quiescent current (80 μA typical), ON/OFF logic control threshold (1.3 V), and TO-220/TO-263 package compatibility for thermal management.
Technical Context
The LM2596T-3.3/LF03 implements a fixed-frequency PWM buck topology with internal oscillator (127–173 kHz), integrated power switch, and voltage-mode feedback control referenced to a 1.23-V internal bandgap. Its nonsynchronous architecture uses an external catch diode, enabling design flexibility while maintaining efficiency across 0.2–3 A load range.
Thermal protection activates at 150°C junction temperature, and current limiting operates in two stages: peak current limit (3.6–6.9 A) followed by frequency reduction under overload. The ON/OFF pin supports TTL-compatible shutdown with 80 μA standby current and logic threshold of 1.3 V (±0.7 V over temperature).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over line, load, and temperature (–40°C to 125°C) |
| Max Output Current | 3 A DC continuous load capability with thermal derating above 25°C ambient |
| Input Voltage Range | 4.5 V to 40 V - supports wide-input industrial and automotive battery-fed systems |
| Switching Frequency | 150 kHz nominal (110–173 kHz over temperature) - enables compact LC filter design |
| Efficiency | 73% typical at VIN = 12 V, IOUT = 3 A - balances switching loss vs. conduction loss |
| Quiescent Current | 80 μA typical in shutdown mode - enables low-power system-level sleep states |
| Feedback Reference | 1.23 V internal reference - sets output via resistor divider only in adjustable versions; fixed version bypasses this path |
Pinout & Package
LM2596T-3.3/LF03 is available in TO-220 (NDH, 5-pin) and TO-263 (KTT, 5-pin) packages. Both use identical pinout and thermal pad configuration. The TO-220 variant features vertical lead bend for through-hole mounting; TO-263 is surface-mount with exposed thermal tab soldered to PCB copper.
| 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 pulsed switch current |
| 2 - OUTPUT | Internal power switch drain | Swings between ~VIN–1.4 V and –0.5 V; connects to catch diode anode and inductor - minimal PCB copper area required |
| 3 - GROUND | Power and signal reference | Common return for input cap, output cap, feedback network, and thermal pad - must be low-impedance plane |
| 4 - FEEDBACK | Voltage sense input | Internally connected to 3.3-V output in fixed version; unused and left open in LM2596T-3.3/LF03 |
| 5 - ON/OFF | Logic-controlled enable | Pull ≤1.3 V to enable; pull ≥1.3 V to enter 80-μA standby - compatible with microcontroller GPIO |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3-V output | Eliminates external feedback resistors - reduces BOM count and layout sensitivity for standard logic rail generation |
| TTL-compatible shutdown | Enables system-level power sequencing and low-power sleep modes without external level shifters |
| Integrated thermal shutdown | Protects against sustained overload or poor heatsinking - automatically recovers when junction cools below 150°C |
| Two-stage current limiting | Prevents catastrophic failure during short-circuit: first limits peak switch current, then reduces frequency to limit average power |
| 150-kHz fixed oscillator | Allows use of standard off-the-shelf inductors and simplifies EMI filtering versus variable-frequency alternatives |
Applications
| Industrial Power Supply | Embedded Control System |
|---|---|
Use Scenario: Converting 24-V DC bus to 3.3-V logic rail for PLC I/O modules operating in harsh factory environments. IC Role / Device Role / Timing Role: Primary step-down regulator delivering clean, regulated 3.3 V to microcontrollers, sensors, and communication interfaces. Use Value: 3-A capability supports multiple peripherals; ±4% output tolerance ensures reliable digital logic operation across temperature extremes. | Use Scenario: Powering ARM Cortex-M based edge node in smart meter or gateway with intermittent wireless transmission. IC Role / Device Role / Timing Role: Main DC-DC converter supplying core voltage to MCU and RF transceiver during active bursts. Use Value: 80-μA shutdown current extends battery life during idle periods; 40-V max input accommodates wide-range unregulated sources. |
| Home Theater AV Receiver | Appliance Control Board |
Use Scenario: Generating 3.3-V supply for HDMI controller, audio DSP, and display interface in multi-rail consumer AV equipment. IC Role / Device Role / Timing Role: Secondary regulated rail derived from main 12-V or 24-V supply, isolated from noisy analog sections. Use Value: Fixed 3.3-V output eliminates tuning; 150-kHz switching allows compact filter design without infringing on audio band. | Use Scenario: Providing stable 3.3-V power to touch panel MCU and sensor hub in refrigerator or washing machine control board. IC Role / Device Role / Timing Role: Isolated low-noise digital rail decoupled from motor drive and relay switching noise. Use Value: Integrated current and thermal protection prevents field failures due to condensation-induced shorts or thermal stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596SX-3.3/NOPB | Same silicon die, TO-263-5 (KTT) package with exposed thermal pad - lower thermal resistance (20°C/W with 3-in² double-sided copper) | Better thermal performance in space-constrained SMT designs; requires reflow-compatible layout | Select when PCB real estate is limited and thermal margin is critical; not drop-in for through-hole boards |
| LMR51430RGER | Synchronous buck, 4.5–36 V input, 3 A, 500 kHz/1.1 MHz, integrated MOSFETs - higher efficiency (92% typ), smaller solution size | Requires no external diode; supports higher switching frequencies for ultra-compact designs; lacks 40-V input rating | Choose for new designs prioritizing efficiency and footprint; not suitable for 36–40 V input or legacy LM2596 drop-in replacement |
Compared with LM2596T-3.3/LF03, LM2596SX-3.3/NOPB offers identical electrical specs in a thermally superior SMT package, while LMR51430RGER delivers higher efficiency and integration at the cost of reduced input voltage range and non-pin-compatibility.
Availability
LM2596T-3.3/LF03 is available at Aetrix Electronics and suitable for industrial power supplies, embedded control systems, home theater receivers, and appliance control boards requiring stable component supply and long-term manufacturability.
Supply support for LM2596T-3.3/LF03 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 specializing in analog and embedded processing technologies, with leadership in power management ICs since the 1980s.
The LM2596 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for ease-of-use in cost-sensitive, medium-power DC-DC applications where reliability, thermal robustness, and minimal external components are essential.
FAQ
What is the output voltage tolerance of the LM2596T-3.3/LF03 across operating conditions?
The LM2596T-3.3/LF03 delivers a fixed 3.3-V output with ±4% maximum tolerance over full line (4.5–40 V), load (0.2–3 A), and temperature (–40°C to +125°C) conditions. This specification is guaranteed per TI's SNVS124G datasheet Section 7.5 and ensures compatibility with standard 3.3-V logic families without additional regulation.
Does the LM2596T-3.3/LF03 require external feedback resistors?
No, the LM2596T-3.3/LF03 does not require external feedback resistors. As a fixed-output variant, its internal feedback network is factory-trimmed to 3.3 V. Pin 4 (FEEDBACK) is internally connected and must be left unconnected - unlike the adjustable LM2596 version which requires an external resistor divider.
What thermal package options are available for the LM2596T-3.3/LF03?
The LM2596T-3.3/LF03 is offered in two thermally optimized packages: TO-220 (NDH, 5-pin) with 50°C/W junction-to-ambient resistance on standard 1-in² copper, and TO-263 (KTT, 5-pin) with 20°C/W achievable using 3-in² double-sided copper. Both share identical pinout and electrical specs.
How does the ON/OFF pin function on the LM2596T-3.3/LF03?
The ON/OFF pin (Pin 5) of the LM2596T-3.3/LF03 enables logic-level control: pulling it ≤1.3 V (at 25°C) turns the regulator on; pulling it ≥1.3 V shuts it down, reducing total input current to 80 μA typical. It accepts voltages up to 25 V and draws <15 μA, making it directly compatible with 3.3-V or 5-V GPIO outputs.
Can the LM2596T-3.3/LF03 be used in inverting (negative output) configurations?
Yes, the LM2596T-3.3/LF03 can be configured as an inverting regulator to generate negative output voltages (e.g., –3.3 V), though this requires reconfiguring the ground and feedback connections per TI's Figure 8-5. Note that the fixed 3.3-V version's internal feedback is not accessible, so output magnitude remains 3.3 V referenced to the new ground node.
LM2596T-3.3/LF03 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-5 Formed Leads
- Packaging:
- Bulk
- Product Status:
- Active
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-5
LM2596T-3.3/LF03 FAQ
1.How can I place an order for LM2596T-3.3/LF03 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2596T-3.3/LF03 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 LM2596T-3.3/LF03 reliable?
The price and inventory of LM2596T-3.3/LF03 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2596T-3.3/LF03 is usually 5 days.
3.What payment methods are accepted for LM2596T-3.3/LF03?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2596T-3.3/LF03 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2596T-3.3/LF03?
LM2596T-3.3/LF03 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2596T-3.3/LF03 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 LM2596T-3.3/LF03?
For technical support, including LM2596T-3.3/LF03 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2596T-3.3/LF03 requirements.
6.How does Aetrix verify that LM2596T-3.3/LF03 is sourced from the original manufacturer or authorized distributors?
All LM2596T-3.3/LF03 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 LM2596T-3.3/LF03 meets industry standards.
7.What is the process for return or replacement of LM2596T-3.3/LF03?
All LM2596T-3.3/LF03 units undergo pre-shipment inspection (PSI). If there is an issue with LM2596T-3.3/LF03, 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 LM2596T-3.3/LF03 part is unused and in its original packaging.
Return procedure for LM2596T-3.3/LF03:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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