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Microchip Technology LM2574-12BN
- Part No.:
- LM2574-12BN
- Manufacturer:
- Microchip Technology
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2574-12BN.pdf
- Description:
- IC REG BUCK 12V 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,088
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Product details
Overview
LM2574-12BN from Micrel is a fixed-output 12V, 0.5A step-down (buck) switching regulator in an 8-pin plastic DIP package, featuring 52kHz internal oscillator, thermal shutdown, cycle-by-cycle current limiting, and <200µA standby current. It operates from 15V to 40V input and delivers ±4% output voltage accuracy across line and load conditions for industrial power supply rails.
For engineers reviewing the LM2574-12BN datasheet, LM2574-12BN pinout, LM2574-12BN application, or LM2574-12BN equivalent, key selection criteria include guaranteed 0.5A output current, fixed 12V output with no external feedback resistors, 85°C/W junction-to-ambient thermal resistance, and compatibility with standard off-the-shelf inductors in buck topology designs.
Technical Context
The LM2574-12BN integrates a 52kHz fixed-frequency oscillator, PWM comparator, error amplifier with 1.23V internal reference, and a bipolar NPN output switch with built-in current limit and thermal shutdown. Its architecture requires only four external components - input capacitor, output capacitor, catch diode, and inductor - to form a complete buck regulator.
It uses a single-ended, non-synchronous buck topology with PWR GND and SIG GND pins separated for noise isolation. The ON/OFF pin enables logic-level shutdown with <200µA quiescent current, and the fixed 12V output eliminates feedback resistor network design complexity while maintaining ±4% regulation over temperature and load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12V ±4% over 0.1–0.5A load and 15–40V input - ensures stable rail without feedback tuning. |
| Max Output Current | 0.5A continuous - supports moderate-power loads like microcontroller peripherals or analog circuitry. |
| Input Voltage Range | 15V to 40V (absolute max 45V) - suitable for unregulated 24V industrial or automotive-derived supplies. |
| Switching Frequency | 52kHz ±10% - enables use of low-cost, high-saturation-current inductors and reduces EMI filtering burden. |
| Efficiency | 88% typical at VIN=25V, IOUT=0.1A - minimizes thermal rise in DIP package without heatsink. |
| Standby Current | <200µA at ON/OFF = 5V - enables low-power sleep modes in battery-backed or energy-conscious systems. |
| Thermal Resistance | 85°C/W (Junction-to-Ambient, N package) - defines safe power dissipation limit under PCB copper layout constraints. |
Pinout & Package
LM2574-12BN is housed in an 8-pin plastic DIP (N package), with pins spaced on 0.100" centers and total body dimensions of 0.380" × 0.320". Thermal performance relies on soldering all pins to PCB copper for heat transfer; NC pins (1 and 8) are recommended for soldering to maximize thermal conduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | NC (No Connect) | Solder to PCB ground plane for enhanced thermal dissipation; not electrically connected internally. |
| 2 | SIG GND | Analog ground reference for feedback and error amplifier - must be routed separately from power ground to avoid noise coupling. |
| 3 | ON/OFF | Logic-controlled shutdown input: ≥2.2V disables regulator (standby), ≤1.2V enables operation. |
| 4 | PWR GND | Power ground return for output switch and catch diode - connects to high-current paths and bulk capacitors. |
| 5 | VIN | Main input supply connection (15–40V); requires local 22µF/40V ceramic or electrolytic bypass. |
| 6 | OUTPUT | Switched output node driving inductor; connects to catch diode cathode and output filter capacitor. |
| 7 | FB | Feedback input - internally tied to 12V divider; unused in fixed-output version but must remain unconnected. |
| 8 | NC (No Connect) | Solder to PCB ground plane for enhanced thermal dissipation; not electrically connected internally. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 12V Output | Eliminates external feedback resistor network, reducing BOM count and layout sensitivity while guaranteeing ±4% regulation. |
| Integrated Protection | Thermal shutdown and cycle-by-cycle current limiting prevent damage during overload, short-circuit, or high-temperature operation. |
| Low Standby Power | Sub-200µA quiescent current in shutdown mode enables long-term battery-backed operation or system-level power gating. |
| Minimal External Parts | Only four components required - input cap, output cap, catch diode, and inductor - simplifying design validation and cost control. |
| Standard Inductor Compatibility | 52kHz switching frequency allows use of widely available, low-cost 330µH shielded inductors rated for ≥0.7A saturation current. |
Applications
| Industrial 24V-to-12V Conversion | Microcontroller Power Supply |
|---|---|
|
Use Scenario: Converting unregulated 24V factory bus to clean 12V for PLC I/O modules or sensor signal conditioning circuits. IC Role / Device Role / Timing Role: Primary DC-DC buck regulator providing isolated, regulated 12V rail with thermal protection against ambient temperature spikes. Use Value: Delivers 0.5A at 88% efficiency without heatsink, reducing board space and thermal management overhead in enclosed enclosures. |
Use Scenario: Powering 12V-tolerant microcontrollers (e.g., PIC18F, STM32H7) and associated peripherals in embedded control units. IC Role / Device Role / Timing Role: Fixed-output step-down regulator supplying stable 12V VDD rail with fast transient response to processor load changes. Use Value: Maintains ±4% output accuracy across –40°C to +85°C, ensuring reliable reset behavior and ADC reference stability. |
| Legacy Equipment Retrofit | Positive-to-Negative Converter |
|
Use Scenario: Replacing aging linear regulators in legacy test equipment where 24V input must generate 12V at up to 500mA with minimal thermal redesign. IC Role / Device Role / Timing Role: Drop-in switching replacement for 7812-style linear regulators, leveraging existing DIP footprint and thermal pad layout. Use Value: Reduces power dissipation from >6W (linear) to ~0.7W (switching), eliminating need for mechanical heatsinks and improving MTBF. |
Use Scenario: Generating –12V rail from +12V or +24V source using buck-boost configuration for op-amp dual supplies. IC Role / Device Role / Timing Role: Core switching controller in inverting buck-boost topology, where OUTPUT pin drives inductor to ground and FB remains open. Use Value: Enables generation of negative voltage with same 52kHz frequency and protection features, avoiding dedicated inverting ICs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574-12W | Same electrical specs but in 14-pin wide SOIC (WM) package with θJA = 100°C/W - lower thermal performance than DIP. | Preferred for surface-mount assembly; requires different PCB footprint and reflow profile. | Select LM2574-12W only when SMT manufacturing is mandatory and thermal margin permits higher junction rise. |
| LM2596-12 | Higher 3A output current, 150kHz switching, adjustable feedback (requires external resistors), and improved efficiency (≥92%). | Supports higher-power loads and tighter regulation; not pin-compatible and requires full schematic/layout revision. | Choose LM2596-12 when upgrading power capability or efficiency is critical; LM2574-12BN remains optimal for legacy DIP-based designs with 0.5A needs. |
Compared with LM2574-12W and LM2596-12, the LM2574-12BN offers proven DIP-mount reliability, minimal external part count, and thermal performance optimized for through-hole PCB layouts - making it ideal for industrial retrofits and low-volume control boards where layout change is constrained.
Availability
LM2574-12BN is available at Aetrix Electronics and suitable for industrial automation, embedded control, and legacy equipment maintenance requiring stable component supply and long-lifecycle support.
Supply support for LM2574-12BN 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
Micrel Inc. was a U.S.-based semiconductor company specializing in analog, power management, and timing solutions before its acquisition by Microchip Technology in 2015.
The LM2574 family was designed for simple, robust, low-component-count DC-DC conversion in industrial, telecom, and embedded systems where reliability and ease of implementation outweigh ultra-high efficiency demands.
FAQ
What is the maximum input voltage rating for the LM2574-12BN?
The LM2574-12BN has an absolute maximum input voltage of 45V, with a recommended operating range of 15V to 40V. Exceeding 45V risks permanent damage to the internal NPN switch and protection circuitry. For reliable operation, maintain VIN within the specified 15–40V window, especially under transient conditions.
Does the LM2574-12BN require external feedback resistors?
No - the LM2574-12BN is a fixed-output variant with internal 12V feedback divider. The FB pin is not connected internally for this part and must remain unconnected in the circuit. This eliminates resistor tolerance errors and simplifies layout versus adjustable versions like the LM2574-ADJ.
Can the LM2574-12BN be used in a buck-boost (inverting) configuration?
Yes - the LM2574-12BN can be configured as a positive-to-negative converter per Figure 1 in the datasheet. In this mode, the OUTPUT pin drives the inductor to ground, and the FB pin remains open. Output polarity reverses, yielding –12V with same regulation and protection features as the standard buck mode.
What is the thermal performance limitation of the LM2574-12BN in its DIP package?
The LM2574-12BN in the 8-pin plastic DIP (N) package has a junction-to-ambient thermal resistance (θJA) of 85°C/W. At 0.5A output and 25V input, power dissipation is ~0.7W, resulting in ~60°C junction rise above ambient - well within the 150°C max rating when mounted on standard FR-4 with adequate copper area.
How does the ON/OFF pin function on the LM2574-12BN?
The ON/OFF pin (Pin 3) controls regulator enable/disable: applying ≤1.2V (typically 0V) enables operation; applying ≥2.2V (typically 5V) places LM2574-12BN in standby mode with quiescent current <200µA. No pull-up/down is required - the pin is CMOS-compatible and draws <30µA in either state.
LM2574-12BN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- -
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- Current - Output:
- 500mA
- Frequency - Switching:
- 52kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2574-12BN FAQ
1.How can I place an order for LM2574-12BN through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2574-12BN 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 LM2574-12BN reliable?
The price and inventory of LM2574-12BN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2574-12BN is usually 5 days.
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Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2574-12BN?
LM2574-12BN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2574-12BN 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 LM2574-12BN?
For technical support, including LM2574-12BN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2574-12BN requirements.
6.How does Aetrix verify that LM2574-12BN is sourced from the original manufacturer or authorized distributors?
All LM2574-12BN 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 LM2574-12BN meets industry standards.
7.What is the process for return or replacement of LM2574-12BN?
All LM2574-12BN units undergo pre-shipment inspection (PSI). If there is an issue with LM2574-12BN, 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 LM2574-12BN part is unused and in its original packaging.
Return procedure for LM2574-12BN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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