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Microchip Technology LM2575BT
- Part No.:
- LM2575BT
- Manufacturer:
- Microchip Technology
- Package:
- TO-220-5
- Datasheet:
-
LM2575BT.pdf
- Description:
- IC REG BUCK ADJ 1A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:7,489
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Product details
Overview
LM2575BT from Texas Instruments is a 1-A step-down switching regulator IC in TO-220 package, featuring 40-V input voltage rating, fixed 5-V output, 52-kHz switching frequency, and internal 3-A switch. It serves as the main DC-DC power conversion stage in industrial power supplies requiring regulated 5-V rail generation from unregulated 7–40-V sources.
For engineers reviewing the LM2575BT datasheet, LM2575BT pinout, LM2575BT application, or LM2575BT equivalent, key selection considerations include its fixed-output architecture, thermal performance in TO-220 with tab-connected to VIN, dropout behavior under load transients, and compatibility with standard buck external components (diode, inductor, capacitors).
Technical Context
The LM2575BT implements a monolithic buck converter with internal NPN transistor switch, PWM control, and thermal shutdown. It uses a 52-kHz oscillator to drive the power stage and includes built-in current limiting and overtemperature protection.
Feedback is provided via an internal 1.23-V reference and error amplifier comparing output voltage against this threshold through external resistor divider - though not applicable for the fixed 5-V version (LM2575BT-5.0), where feedback is internally connected.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±2%, eliminates need for external feedback resistors |
| Max Input Voltage | 40 V - supports wide-input industrial and automotive battery-fed systems |
| Output Current | 1 A continuous - requires heatsinking in TO-220 when operating above ~0.5 A at high ambient |
| Switching Frequency | 52 kHz - enables use of low-cost, high-inductance toroidal inductors and reduces EMI filtering complexity |
| Thermal Shutdown | Activates at ~150°C junction temperature - protects device during overload or poor heatsinking |
| Current Limit | Internally set at ~3 A peak - provides short-circuit robustness without external sensing |
Pinout & Package
LM2575BT is housed in a 5-pin TO-220 package with metal tab electrically connected to VIN pin for thermal conduction and electrical reference. The tab must be isolated from chassis ground unless VIN is referenced to system ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply | Connects to unregulated DC source (7–40 V); metal tab is bonded to this pin |
| OUT | Regulated output node | Drives inductor and output capacitor; connects directly to load |
| GND | Power and signal ground | Common return for internal circuitry and external components |
| FEEDBACK | Output voltage sense input | Internally tied to 5-V divider - no external connection required for LM2575BT-5.0 |
| ON/OFF | Enable/disable control | Logic-high (>1.3 V) enables regulation; grounded or open disables output |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3-A NPN switch | Reduces external component count and PCB footprint versus controller-based solutions |
| Fixed 5-V output configuration | Eliminates feedback resistor network, improving accuracy and reducing BOM cost |
| 52-kHz fixed-frequency operation | Enables predictable EMI filtering design and simplifies inductor selection |
| Thermal shutdown + current limit | Provides autonomous fault protection without external monitoring circuitry |
| TO-220 package with VIN-connected tab | Allows direct mounting to heatsink while maintaining VIN reference for thermal path |
Applications
| Industrial Power Supply | Automotive Aftermarket Electronics |
|---|---|
Use Scenario: Generating stable 5-V rail from 12/24-V vehicle battery or factory 24-V DC bus. IC Role / Device Role / Timing Role: Primary non-isolated DC-DC buck regulator providing main logic supply. Use Value: Tolerates load dumps up to 40 V and sustains 1-A load with minimal external parts. | Use Scenario: Powering microcontroller-based dash cameras, GPS trackers, or CAN gateways. IC Role / Device Role / Timing Role: Point-of-load regulator converting battery voltage to clean 5-V for digital subsystems. Use Value: Built-in current limit and thermal shutdown prevent field failures due to wiring faults or enclosure overheating. |
| Embedded Control Module | Legacy Equipment Retrofit |
Use Scenario: Replacing linear regulators (e.g., 7805) in PLC I/O modules to reduce heat and improve efficiency. IC Role / Device Role / Timing Role: High-efficiency replacement for obsolete 78xx series in space-constrained enclosures. Use Value: Delivers same 5-V output at >75% efficiency vs. <40% for linear regulators at 24-V input. | Use Scenario: Upgrading aging test equipment or instrumentation with modern power architecture. IC Role / Device Role / Timing Role: Standalone drop-in upgrade for fixed 5-V supply sections using existing TO-220 footprint. Use Value: Maintains mechanical compatibility while enabling higher input voltage tolerance and thermal resilience. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2575HVT-5.0 | Higher 60-V max input rating; otherwise identical pinout, function, and specs | Suitable for 48-V telecom or heavy-duty vehicle systems exceeding 40-V transients | Select when input may exceed 40 V; same layout and thermal design apply |
| LM2596T-5.0 | 1.5-A output, 150-kHz switching, different pinout (no ON/OFF pin), requires external feedback for adjustable versions | Better suited for higher-current or smaller-filter designs; not pin-compatible | Choose for increased output current or higher-frequency operation; redesign PCB and filter components required |
Compared with LM2575HVT-5.0, the LM2575BT offers lower cost and proven reliability in 40-V-limited environments; compared with LM2596T-5.0, it provides simpler enable control and legacy design continuity but lower current capability and larger magnetics.
Availability
LM2575BT is available at Aetrix Electronics and suitable for industrial power supplies, automotive aftermarket electronics, and embedded control modules requiring stable component supply and long-term manufacturability.
Supply support for LM2575BT 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 U.S.-based semiconductor company specializing in analog and embedded processing technologies with broad industrial and automotive product portfolios.
The LM2575BT belongs to TI's classic SIMPLE SWITCHER® buck regulator family, designed for ease of use, high reliability, and minimal external component count in cost-sensitive DC-DC applications.
FAQ
What is the maximum input voltage rating for the LM2575BT?
The LM2575BT has a maximum input voltage rating of 40 V. This specification is absolute maximum and applies across the full operating temperature range. Exceeding 40 V risks permanent damage. Transient spikes must be clamped externally if system-level inputs (e.g., automotive battery) can exceed this limit. The LM2575BT does not include input overvoltage protection beyond this rating.
Does the LM2575BT require external feedback resistors to set output voltage?
No, the LM2575BT is the fixed 5-V version of the LM2575 family and contains internal feedback resistors. The FEEDBACK pin is pre-connected to generate exactly 5.0 V ±2%. External resistors are unnecessary and should not be added, as they would disrupt regulation. Adjustable versions (e.g., LM2575T-ADJ) require external resistors.
Can the LM2575BT be used without a heatsink?
The LM2575BT can operate without an external heatsink at light loads (<300 mA) and ambient temperatures below 50°C. At full 1-A load, junction temperature rises significantly in TO-220; thermal calculations show ≥20°C/W heatsink required for reliable operation above 25°C ambient. The metal tab is connected to VIN, so electrical isolation from chassis is mandatory unless VIN is system ground-referenced.
What is the purpose of the ON/OFF pin on the LM2575BT?
The ON/OFF pin enables or disables the LM2575BT's switching operation. Applying ≥1.3 V (up to VIN) enables regulation; grounding or leaving it open disables output. This allows system-level power sequencing, standby mode control, or fault-initiated shutdown. Unlike enable pins on newer regulators, it lacks hysteresis or precise threshold - simple logic-level control suffices.
How does the LM2575BT compare to linear regulators like the 7805 in terms of efficiency?
At 24-V input and 1-A load, the LM2575BT achieves ~75–80% efficiency, dissipating ~5 W total. A 7805 under identical conditions operates at ~21% efficiency and dissipates ~19 W as heat - requiring large heatsinks. The LM2575BT's switching architecture eliminates this thermal burden, making it essential for higher input-to-output voltage ratios where linear regulators become impractical.
LM2575BT 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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 1A
- 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
LM2575BT FAQ
1.How can I place an order for LM2575BT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2575BT 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 LM2575BT reliable?
The price and inventory of LM2575BT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2575BT is usually 5 days.
3.What payment methods are accepted for LM2575BT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575BT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2575BT?
LM2575BT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2575BT 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 LM2575BT?
For technical support, including LM2575BT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575BT requirements.
6.How does Aetrix verify that LM2575BT is sourced from the original manufacturer or authorized distributors?
All LM2575BT 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 LM2575BT meets industry standards.
7.What is the process for return or replacement of LM2575BT?
All LM2575BT units undergo pre-shipment inspection (PSI). If there is an issue with LM2575BT, 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 LM2575BT part is unused and in its original packaging.
Return procedure for LM2575BT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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