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Texas Instruments LM2596T-3.3
- Part No.:
- LM2596T-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LM2596T-3.3.pdf
- Description:
- IC REG BUCK 3.3V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,628
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Product details
Overview
LM2596T-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 ±4% output voltage tolerance over line and load, and featuring TTL-compatible ON/OFF control and thermal/current protection. It serves as the primary power conversion stage in mid-power embedded systems requiring stable 3.3-V rail generation from unregulated inputs up to 40 V.
For engineers reviewing the LM2596T-3.3 datasheet, LM2596T-3.3 pinout, LM2596T-3.3 application, or LM2596T-3.3 equivalent, key selection criteria include input voltage range (4.5–40 V), output accuracy (3.168–3.432 V at 25°C), efficiency (73% at 12 VIN/3 A), thermal performance (RθJA = 50°C/W in TO-220), and shutdown quiescent current (80 μA typical).
Technical Context
The LM2596T-3.3 integrates a PWM controller, power switch, and internal frequency compensation in a monolithic buck topology. Its fixed 150-kHz oscillator enables use of standard off-the-shelf inductors while minimizing filter size versus lower-frequency regulators. The device operates in continuous conduction mode by default but supports discontinuous mode at light loads.
Control is implemented via voltage-mode feedback using an internal 1.23-V reference and external resistor divider for adjustable versions - though the LM2596T-3.3 uses factory-trimmed internal resistors to fix VOUT at 3.3 V. Protection includes two-stage current limiting (peak limit 3.6–6.9 A) and thermal shutdown at 150°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3 V ±4% (3.168–3.432 V at 25°C; ensures reliable logic-level compliance for 3.3-V microcontrollers and FPGAs) |
| Max Output Current | 3 A DC (supports single-rail power for mid-complexity SoCs, DSPs, or sensor hubs without external current boosting) |
| Input Voltage Range | 4.5 V to 40 V (accepts wide-range industrial supplies, automotive batteries, or rectified AC adapters) |
| Switching Frequency | 150 kHz (fixed; enables compact LC filters using standard 33–100 μH inductors and reduces EMI compared to sub-100-kHz designs) |
| Efficiency | 73% at 12 VIN, 3 A (delivers >2.4 W of usable 3.3-V power with <1 W dissipation in TO-220 package under typical conditions) |
| Quiescent Current | 80 μA in shutdown (enables ultra-low-power system sleep states without auxiliary LDOs) |
| Thermal Resistance | RθJA = 50°C/W (TO-220 NDH package; requires ≥1 in² copper pour for full 3-A operation at 125°C ambient) |
Pinout & Package
LM2596T-3.3 is supplied in a 5-pin TO-220 (NDH) package with vertical lead bend, featuring exposed tab for thermal conduction to heatsink or PCB copper. The package measures 14.986 mm × 10.16 mm (L × W) and is RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Positive input supply | Accepts 4.5–40 V; requires low-ESR input capacitor (≥100 μF) placed within 5 mm to suppress switching transients |
| 2 - OUTPUT | Internal power switch drain | Swings between ~VIN−1.4 V and −0.5 V; connects to catch diode anode and inductor; PCB copper area must be minimized to reduce EMI coupling |
| 3 - GROUND | Circuit reference node | Common return for input cap, output cap, feedback network, and heatsink; must be low-impedance star point |
| 4 - FEEDBACK | Voltage sense input | Internally connected to 3.3-V divider; unused on fixed-output version - leave unconnected or tie to GND per layout guidelines |
| 5 - ON/OFF | Logic-controlled enable | TTL-compatible: <1.3 V = ON, >1.3 V = OFF; draws ≤200 μA in shutdown; can be tied to GND for always-on operation |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3-V output | Eliminates external feedback resistor network, reducing BOM count and layout sensitivity while guaranteeing ±4% regulation across temperature and load |
| Integrated thermal shutdown | Automatically disables switching at 150°C junction temperature, preventing permanent damage during overload or poor heatsinking |
| Two-stage current limiting | First stage limits peak switch current to ~4.5 A (typical); second stage reduces switching frequency under sustained overload to limit average power dissipation |
| Low shutdown IQ | Draws only 80 μA (typical) when disabled, enabling battery-backed systems to maintain weeks of standby time without recharge |
| Standard inductor compatibility | Works with widely available 33–100 μH shielded power inductors rated ≥3.5 A DC, avoiding custom magnetics and accelerating design cycle |
Applications
| Industrial PLC I/O Module | Embedded Network Router |
|---|---|
Use Scenario: Powering isolated 3.3-V digital I/O banks in DIN-rail mounted programmable logic controllers with 24-V DC field supply. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator generating clean 3.3-V rail for microcontroller, CAN transceivers, and optocoupler drivers. Use Value: Delivers 3 A continuously at 73% efficiency from 24-V input, reducing thermal load versus linear regulators and enabling convection-cooled metal enclosures. | Use Scenario: Supplying 3.3-V core voltage to MIPS-based networking SoC and Ethernet PHYs in fanless residential gateways. IC Role / Device Role / Timing Role: Main system power converter converting 12-V adapter input to regulated 3.3-V domain with tight transient response for bursty packet processing. Use Value: Fixed 3.3-V output eliminates feedback tuning; 150-kHz switching allows small 47-μH inductor and 220-μF output capacitor, fitting constrained board space. |
| Home Theater AV Receiver | Point-of-Sale Terminal |
Use Scenario: Generating 3.3-V logic supply for HDMI controller, audio DAC, and touch interface MCU in multi-rail consumer AV equipment. IC Role / Device Role / Timing Role: Secondary buck regulator fed from 5-V intermediate rail, providing noise-isolated 3.3-V domain with low standby IQ. Use Value: 80-μA shutdown current enables instant-on capability with zero-volt standby; ±4% output tolerance ensures HDMI compliance under varying load steps. | Use Scenario: Powering 3.3-V ARM Cortex-M7 MCU, display driver, and contactless payment module in compact retail terminals with 12-V wall adapter input. IC Role / Device Role / Timing Role: Single-chip solution replacing discrete buck controller + MOSFET, simplifying certification and reducing bill-of-materials. Use Value: TO-220 package allows direct heatsink mounting; integrated current limit protects against short-circuited displays or damaged USB peripherals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-3.3 | Surface-mount TO-263 (KTT) package; identical electrical specs; RθJA = 30°C/W with 2.5 in² copper | Better thermal performance in space-constrained PCBs; requires reflow soldering instead of through-hole assembly | Select when automated SMT production is used and board real estate is limited. |
| LMR51430RGER | Synchronous buck; 4.5–36 V input; 3 A; 500 kHz/1.1 MHz; 92% efficiency at 12 VIN/3 A; requires external compensation | Higher efficiency and smaller total solution size, but needs additional design effort for loop stability and EMI filtering | Select when >90% efficiency or <1 MHz switching is required and design resources allow tuning. |
Compared with LM2596T-3.3, the LM2596S-3.3 offers identical regulation and protection in a thermally superior surface-mount package, while the LMR51430RGER delivers significantly higher efficiency and frequency flexibility at the cost of increased design complexity and loss of pin-to-pin compatibility.
Availability
LM2596T-3.3 is available at Aetrix Electronics and suitable for industrial automation, embedded networking, and consumer electronics applications requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.
Supply support for LM2596T-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 with over 90 years of innovation history.
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 high-frequency operation.
FAQ
What is the maximum input voltage rating for the LM2596T-3.3?
The LM2596T-3.3 has an absolute maximum input voltage rating of 45 V, but its recommended operating input voltage range is 4.5 V to 40 V. Operation above 40 V risks exceeding safe operating area limits and may trigger internal protection or cause premature failure. For reliable 3-A operation, input should remain ≤40 V with adequate derating for thermal margin.
Does the LM2596T-3.3 require external feedback resistors?
No, the LM2596T-3.3 does not require external feedback resistors. It is a fixed-output variant with internal resistor divider trimmed to deliver 3.3 V ±4%. Pin 4 (FEEDBACK) is internally connected and must be left unconnected or tied to ground per TI layout recommendations - no external components are needed for voltage setting.
How does the ON/OFF pin function on the LM2596T-3.3?
The ON/OFF pin (Pin 5) provides logic-level enable control: pulling it below 1.3 V (at 25°C) turns the LM2596T-3.3 ON, while pulling it above 1.3 V shuts it down, reducing quiescent current to 80 μA typical. If unused, it may be tied directly to GND for permanent enable. The pin tolerates up to 25 V and draws ≤15 μA in either state.
What thermal management is required for full 3-A operation of the LM2596T-3.3?
For continuous 3-A output at 125°C ambient, the LM2596T-3.3 in TO-220 package requires a minimum 1 in² copper pour (1 oz.) connected to the tab, plus optional external heatsink. Without added copper or heatsink, thermal derating begins above ~1.5 A at 25°C ambient due to its 50°C/W junction-to-ambient resistance. Thermal shutdown activates at 150°C junction temperature.
Can the LM2596T-3.3 be used in an inverting (buck-boost) configuration?
Yes, the LM2596T-3.3 can be configured as an inverting regulator to generate negative output voltages (e.g., −3.3 V), though this requires modified external circuitry including level-shifted ON/OFF control and additional diodes. TI provides reference schematics (Figure 8-5) and cautions that startup current may reach 4.5 A transiently, requiring careful input capacitance and source selection.
LM2596T-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-220-5 Formed Leads
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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 FAQ
1.How can I place an order for LM2596T-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2596T-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 LM2596T-3.3 reliable?
The price and inventory of LM2596T-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 LM2596T-3.3 is usually 5 days.
3.What payment methods are accepted for LM2596T-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2596T-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2596T-3.3?
LM2596T-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2596T-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 LM2596T-3.3?
For technical support, including LM2596T-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2596T-3.3 requirements.
6.How does Aetrix verify that LM2596T-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2596T-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 LM2596T-3.3 meets industry standards.
7.What is the process for return or replacement of LM2596T-3.3?
All LM2596T-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2596T-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 LM2596T-3.3 part is unused and in its original packaging.
Return procedure for LM2596T-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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