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Microchip Technology LM2576-3.3BT
- Part No.:
- LM2576-3.3BT
- Manufacturer:
- Microchip Technology
- Package:
- TO-220-5
- Datasheet:
-
LM2576-3.3BT.pdf
- Description:
- IC REG BUCK 3.3V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:945
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Product details
Overview
LM2576-3.3BT from Texas Instruments is a step-down (buck) switching regulator IC delivering fixed 3.3 V output at up to 3 A, with 40 V maximum input voltage, 52 kHz fixed switching frequency, and internal 3.0 A switch. It operates in continuous conduction mode and supports applications requiring robust DC/DC conversion in industrial power supplies.
For engineers reviewing the LM2576-3.3BT datasheet, LM2576-3.3BT pinout, LM2576-3.3BT application, or LM2576-3.3BT equivalent, key selection criteria include output voltage accuracy (±2%), thermal shutdown protection, input voltage range (4.75–40 V), dropout behavior under load, and compatibility with standard external components (inductor, diode, capacitors).
Technical Context
The LM2576-3.3BT integrates a PWM controller, power transistor, and protection circuitry in a single TO-220-5 package. Its oscillator operates at a nominal 52 kHz, enabling use of low-cost, high-inductance toroidal or shielded power inductors. The feedback loop uses an internal 1.23 V reference and resistive divider for regulation stability.
Thermal shutdown activates at junction temperature ≥160 °C, and current-limit protection engages at ~3.0 A typical peak switch current. No external compensation is required - the control loop is internally compensated for stable operation with standard output capacitor ESR ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±2% over line, load, and temperature |
| Max Output Current | 3 A continuous, limited by thermal design and PCB copper area |
| Input Voltage Range | 4.75 V to 40 V - supports 5 V, 12 V, 24 V, and 36 V input rails |
| Switching Frequency | 52 kHz ±10% - enables use of low-ESR electrolytic output capacitors and cost-effective magnetics |
| Efficiency | Up to 88% at 12 VIN/3.3 VOUT/2 A - reduces thermal load vs linear regulators |
| Quiescent Current | 5.5 mA typical in operating mode - enables low-noise standby operation |
Pinout & Package
LM2576-3.3BT is housed in a TO-220-5 (straight lead, non-isolated) thermally enhanced package with exposed tab connected to Pin 2 (Ground). Mounting to heatsink is required for full 3 A operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (IN) | Input voltage supply | Accepts 4.75–40 V DC; requires local 100 µF electrolytic bypass capacitor |
| Pin 2 (GND) | Power ground / thermal pad | Common return for input/output paths and primary thermal path to heatsink |
| Pin 3 (OUT) | Switching node / inductor connection | Drives external catch diode and power inductor; high dv/dt node requiring short trace routing |
| Pin 4 (FEEDBACK) | Regulation sense input | Internally tied to 3.3 V output - no external resistor divider needed |
| Pin 5 (ON/OFF) | Enable/disable control | Logic-high (>2.5 V) enables regulation; grounded or <1.3 V disables output and reduces quiescent current to 20 µA |
Key Features
| Feature | Design Value |
|---|---|
| Internal 3.0 A power switch | Eliminates need for external MOSFET or transistor - simplifies BOM and layout |
| Fixed 3.3 V output | Reduces component count vs adjustable versions; eliminates feedback resistor tolerance errors |
| Thermal shutdown with hysteresis | Protects against sustained overload or inadequate heatsinking without latch-up |
| Output short-circuit protection | Current limiting prevents damage during accidental output-to-ground faults |
| 52 kHz fixed-frequency operation | Enables predictable EMI filtering and avoids audible noise in sensitive environments |
Applications
| Industrial PLC Power Supply | Embedded System Main Rail |
|---|---|
Use Scenario: Powering microcontroller, FPGA, and I/O peripherals in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Primary 3.3 V DC/DC converter supplying core logic and communication interfaces. Use Value: Delivers stable 3.3 V at up to 3 A with input transient tolerance up to 40 V - accommodates 24 V field bus surges. | Use Scenario: Generating main system rail in network-connected edge devices with Ethernet PHY and flash memory. IC Role / Device Role / Timing Role: Buck regulator providing clean, regulated 3.3 V for SoC, RAM, and peripheral ICs. Use Value: High efficiency (88% @ 12 VIN) minimizes board-level heat generation in sealed enclosures. |
| Automotive Body Control Module | Test & Measurement Equipment |
Use Scenario: Powering MCU and CAN transceivers in 12 V battery-powered body electronics modules. IC Role / Device Role / Timing Role: Input-filtered buck regulator supporting cold-crank (4.75 V) and load-dump (up to 40 V) conditions. Use Value: Wide input range and built-in thermal/current protection ensure reliable operation across automotive voltage extremes. | Use Scenario: Providing stable 3.3 V rail for precision ADCs, DACs, and digital signal processors in benchtop instruments. IC Role / Device Role / Timing Role: Low-noise, well-regulated power source for analog front-end and timing circuits. Use Value: Fixed-output accuracy (±2%) and low output ripple (<100 mVpp) support high-resolution measurement integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576T-3.3 | Same electrical specs; TO-220-5 package with isolated tab (no internal GND tie) | Requires insulating washer when mounting to common heatsink; identical thermal performance with proper isolation | Select LM2576T-3.3 if heatsink is shared with other grounded systems and isolation is required |
| MP1584EN-LF-Z | Adjustable output (via external resistors), 1.5 A max, 1.5 MHz switching, smaller SOIC-8 package | Better suited for space-constrained designs needing lower output current and higher frequency for compact LC filters | Choose MP1584EN-LF-Z only when 3 A output is not required and PCB area is critical |
Compared with LM2576T-3.3, the LM2576-3.3BT offers direct GND-tied tab mounting without insulation, simplifying thermal design; versus MP1584EN-LF-Z, it provides higher current capability and lower EMI due to 52 kHz operation, but requires larger external magnetics.
Availability
LM2576-3.3BT is available at Aetrix Electronics and suitable for industrial PLC power supplies, embedded system main rails, and automotive body control modules requiring stable component supply and long-term manufacturability.
Supply support for LM2576-3.3BT 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, embedded processing, and power management technologies.
The LM2576 series was designed as a family of monolithic step-down switching regulators targeting cost-sensitive, medium-power industrial and automotive DC/DC conversion applications.
FAQ
What is the maximum input voltage rating for the LM2576-3.3BT?
The LM2576-3.3BT supports a maximum input voltage of 40 V DC. This rating allows operation across wide industrial and automotive input ranges, including 24 V systems with transient surges and 12 V battery systems under load-dump conditions. Operation above 40 V risks permanent damage to the internal power switch. Always include input transient suppression (e.g., TVS diode) when used in noisy environments.
Does the LM2576-3.3BT require external feedback resistors?
No, the LM2576-3.3BT does not require external feedback resistors. It features a factory-trimmed internal voltage divider that sets the output to a fixed 3.3 V. Pin 4 (FEEDBACK) is internally connected to the output, eliminating resistor tolerance errors and reducing component count. This differs from the adjustable LM2576-ADJ version, which requires two external resistors to set output voltage.
Can the LM2576-3.3BT be used without a heatsink?
The LM2576-3.3BT can deliver up to ~0.5 A continuously without a heatsink under ambient temperatures ≤25 °C and with adequate PCB copper area (≥4 cm² of 2 oz copper on inner layer). For full 3 A operation, a properly mounted heatsink is mandatory - the TO-220-5 tab must be thermally coupled to ≥10 cm² of 2 oz copper or an external aluminum heatsink to maintain junction temperature below 125 °C.
What type of catch diode is recommended for use with the LM2576-3.3BT?
A Schottky diode rated for ≥3 A average forward current and ≥60 V PIV is recommended for the LM2576-3.3BT. Digi-Key part SB560 or ON Semiconductor MBR360 are validated choices. The diode must be placed as close as possible to Pins 2 (GND) and 3 (OUT) to minimize parasitic inductance. Fast recovery diodes may be used but reduce efficiency due to higher forward voltage drop compared to Schottky types.
Is the LM2576-3.3BT RoHS compliant and halogen-free?
Yes, the LM2576-3.3BT is RoHS compliant and halogen-free per Texas Instruments' official product change notification (PCN) SNOR-2019-001. It meets JEDEC J-STD-609 Class 1 for halogen content and is marked with the "RoHS" suffix in TI's packaging documentation. Lead-free solder reflow profiles follow IPC/JEDEC J-STD-020D for TO-220 packages.
LM2576-3.3BT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Bulk
- 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:
- 3A
- Frequency - Switching:
- 52kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
LM2576-3.3BT FAQ
1.How can I place an order for LM2576-3.3BT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576-3.3BT 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 LM2576-3.3BT reliable?
The price and inventory of LM2576-3.3BT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576-3.3BT is usually 5 days.
3.What payment methods are accepted for LM2576-3.3BT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576-3.3BT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576-3.3BT?
LM2576-3.3BT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576-3.3BT 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 LM2576-3.3BT?
For technical support, including LM2576-3.3BT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576-3.3BT requirements.
6.How does Aetrix verify that LM2576-3.3BT is sourced from the original manufacturer or authorized distributors?
All LM2576-3.3BT 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 LM2576-3.3BT meets industry standards.
7.What is the process for return or replacement of LM2576-3.3BT?
All LM2576-3.3BT units undergo pre-shipment inspection (PSI). If there is an issue with LM2576-3.3BT, 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 LM2576-3.3BT part is unused and in its original packaging.
Return procedure for LM2576-3.3BT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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