My Inquiry
My Account
Texas Instruments LM2574N-ADJ/NOPB
- Part No.:
- LM2574N-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2574N-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:880
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2574N-ADJ/NOPB from Texas Instruments (formerly National Semiconductor) is a monolithic 0.5A step-down (buck) switching voltage regulator with adjustable output, internal 52 kHz oscillator, cycle-by-cycle current limiting, thermal shutdown, and TTL-compatible shutdown control. It delivers ±4% output voltage accuracy over line and load, supports 4.75–40V input, and regulates output from 1.23V to 37V using two external resistors. It replaces linear regulators in medium-power DC/DC conversion for industrial power supplies.
For engineers reviewing the LM2574N-ADJ/NOPB datasheet, LM2574N-ADJ/NOPB pinout, LM2574N-ADJ/NOPB application, or LM2574N-ADJ/NOPB equivalent, key selection criteria include its fixed-frequency buck architecture, 0.5A guaranteed output current, 52 kHz switching frequency, feedback voltage of 1.23 V, and DIP-8 package compatibility with minimal external component count (4 total).
Technical Context
The LM2574N-ADJ/NOPB integrates a PWM controller, power switch, oscillator, error amplifier, and protection circuitry into a single DIP-8 IC. Its feedback loop references a precise 1.23 V internal bandgap voltage at the FB pin, enabling programmable output via resistor divider. The 52 kHz fixed-frequency oscillator drives the internal NPN switch with up to 98% duty cycle, supporting wide input-to-output voltage ratios.
Protection features include cycle-by-cycle peak current limiting (1.0 A typical), thermal shutdown at ~150°C junction temperature, and low-quiescent standby mode (50 µA typical) activated by the ON/OFF pin. Input voltage range is 4.75 V to 40 V, and it operates across –40°C to +125°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Guaranteed 0.5 A continuous load capability without external heatsink - copper PCB traces suffice for thermal management. |
| Input Voltage Range | 4.75 V to 40 V - supports wide industrial input rails including 12 V, 24 V, and 36 V systems. |
| Output Voltage Range | 1.23 V to 37 V (adjustable via R1/R2 divider) - enables flexible rail generation from single supply. |
| Feedback Voltage | 1.230 V ±1.3% (min/max over temp & load) - sets output accuracy baseline for resistor-divider design. |
| Switching Frequency | 52 kHz ±10% - fixed internal oscillator enables predictable EMI filtering and inductor selection. |
| Efficiency | 77% at VIN = 12 V, VOUT = 5 V, IOUT = 0.5 A - significantly higher than linear regulators, reducing thermal stress. |
| Standby Current | 50 µA typical at OFF state - enables low-power system sleep modes without auxiliary circuitry. |
Pinout & Package
LM2574N-ADJ/NOPB uses an 8-pin plastic dual-in-line (DIP-8) package (NS package code N08A), with pin 1 marked by a notch or dot. Thermal performance depends on PCB copper area: θJA = 92°C/W (1 in² copper) or 72°C/W (4 in² copper). Pin 5 (GND) and pin 6 (VIN) require short, low-inductance traces for stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts 4.75–40 V DC; requires ≥22 µF electrolytic bypass capacitor placed adjacent to pin. |
| 2 (OUT) | Switch Node / Power Output | Drives external catch diode and inductor; high dv/dt node requiring tight layout to minimize EMI. |
| 3 (GND) | Power Ground Reference | Common return for input cap, output cap, and feedback network; must connect to large copper pour. |
| 4 (FB) | Feedback Input | Senses output via resistor divider; high-impedance (50 nA bias) node sensitive to noise - keep trace short and away from switching paths. |
| 5 (ON/OFF) | Shutdown Control | TTL-compatible logic input; <1.2 V disables regulator (50 µA standby), >2.2 V enables operation. |
| 6 (GND) | Second Ground Terminal | Dedicated ground for internal circuitry; must be tied to pin 3 externally with low-inductance connection. |
| 7 (GND) | Third Ground Terminal | Additional ground pin to reduce thermal resistance and improve current handling - solder to PCB ground plane. |
| 8 (NC) | No Internal Connection | Not bonded internally; recommended to solder to PCB ground for mechanical stability and heat transfer. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 0.5A NPN Switch | Eliminates need for external power transistor - reduces BOM count and layout complexity. |
| Fixed 52 kHz Oscillator | Enables consistent filter design and predictable EMI behavior without external timing components. |
| ±4% Output Voltage Accuracy | Ensures stable regulation across full line/load/temperature range - critical for downstream analog or digital circuits. |
| Cycle-by-Cycle Current Limit | Protects against short-circuit and overload without latch-up - maintains safe operation during transient faults. |
| TTL-Compatible Shutdown | Allows microcontroller or logic-level control of power sequencing with negligible quiescent draw in OFF state. |
Applications
| Industrial Power Supply | Embedded System Pre-regulator |
|---|---|
Use Scenario: Generating 5 V or 12 V from unregulated 24 V DC bus in PLC I/O modules or motor drive control boards. IC Role / Device Role / Timing Role: Primary step-down regulator delivering stable intermediate rail for MCU, sensors, and interface ICs. Use Value: Replaces inefficient linear regulators, reducing board temperature rise and eliminating need for heatsinks in confined enclosures. | Use Scenario: Providing 3.3 V or 5 V pre-regulated input to low-dropout (LDO) linear regulators powering noise-sensitive analog circuits. IC Role / Device Role / Timing Role: High-efficiency bulk converter preceding precision LDOs to minimize total power loss. Use Value: Achieves >75% efficiency at 0.5 A, lowering overall thermal load while maintaining clean, low-noise output after LDO post-regulation. |
| On-Board DC/DC Conversion | Positive-to-Negative Buck-Boost |
Use Scenario: Local power conversion on dense PCBs where space prohibits external DC/DC modules, e.g., in telecom line cards or instrumentation front-ends. IC Role / Device Role / Timing Role: Compact, discrete-component-based buck regulator occupying <1 cm² footprint with standard passive parts. Use Value: Requires only four external components (inductor, diode, two capacitors) - accelerates prototyping and simplifies compliance testing. | Use Scenario: Generating –5 V or –12 V from a positive input rail for op-amp biasing or RS-232 level shifting in mixed-signal systems. IC Role / Device Role / Timing Role: Configured in inverting buck-boost topology using same external parts as buck mode. Use Value: Leverages identical IC and BOM to generate negative rails without adding dedicated inverting controllers or transformers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2575N-ADJ | Higher 1 A output current, 52 kHz frequency, wider 4–40 V input range, but larger SOIC-16 or TO-220 packages. | Preferred where higher load current or better thermal performance is required; not pin-compatible with LM2574N-ADJ/NOPB. | Select when >0.5 A output or improved thermal margin is needed; redesign PCB layout and recalculate feedback network. |
| MP1584EN-LF-Z | 3 A output, 1.5 MHz switching, smaller SOT-23-8 package, but requires external compensation and lacks integrated shutdown logic. | Better suited for compact, high-density designs needing higher current and faster transient response; no direct pin mapping. | Choose for space-constrained, high-efficiency applications; verify stability with external RC compensation and add external enable logic if needed. |
Compared with LM2575N-ADJ and MP1584EN-LF-Z, the LM2574N-ADJ/NOPB offers proven DIP-8 simplicity, minimal external part count, and robust fault protection at 0.5 A - ideal for cost-sensitive, medium-power industrial designs where layout flexibility and ease of debugging outweigh ultra-high density or current demands.
Availability
LM2574N-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, embedded system pre-regulators, on-board DC/DC conversion, and positive-to-negative buck-boost applications requiring stable component supply, long-term lifecycle support, and legacy design continuity.
Supply support for LM2574N-ADJ/NOPB 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 acquired National Semiconductor in 2011 and maintains its legacy analog product lines, including the SIMPLE SWITCHER™ series. TI is a global semiconductor leader focused on analog and embedded processing technologies.
The LM2574N-ADJ/NOPB belongs to the SIMPLE SWITCHER™ family of integrated buck regulators, designed specifically for engineers seeking easy-to-use, reliable, and thermally efficient DC/DC conversion solutions in industrial, automotive, and communications equipment.
FAQ
What is the minimum input voltage required for stable operation of the LM2574N-ADJ/NOPB?
The LM2574N-ADJ/NOPB requires a minimum input voltage of 4.75 V to maintain regulation across its full output range. Below this threshold, the internal circuitry cannot sustain oscillation or proper switch conduction, resulting in dropout or unregulated output. This specification is confirmed in the Electrical Characteristics table under "All Output Voltage Versions" for the adjustable variant, with test conditions explicitly stating VIN = 12 V for the LM2574-ADJ version.
Can the LM2574N-ADJ/NOPB be used in discontinuous conduction mode (DCM)?
Yes, the LM2574N-ADJ/NOPB operates reliably in both continuous and discontinuous conduction modes. Its design accommodates light-load conditions where inductor current falls to zero, as documented in the Application Hints section. Performance metrics such as line regulation and feedback accuracy remain valid in DCM, though output ripple may increase slightly due to larger peak-to-peak inductor current swing.
What is the purpose of the NC pin (Pin 8) on the LM2574N-ADJ/NOPB DIP-8 package?
Pin 8 on the LM2574N-ADJ/NOPB is a no-connect (NC) terminal with no internal bond wire. Per the official datasheet (DS011394-2), it should be soldered to the PCB ground plane to enhance mechanical stability and improve heat transfer from the package body - especially important given the device's 72°C/W thermal resistance with 4 in² copper.
How does the feedback voltage tolerance affect output accuracy in the LM2574N-ADJ/NOPB?
The LM2574N-ADJ/NOPB has a feedback voltage (VFB) of 1.230 V with ±1.3% tolerance (1.217 V to 1.243 V at TJ = 25°C). Since output voltage is set by VOUT = VFB × (1 + R2/R1), this tolerance directly contributes to overall output error. Combined with resistor tolerance and temperature drift, it limits achievable accuracy to approximately ±4% over full operating conditions - matching the guaranteed system-level spec.
Is the LM2574N-ADJ/NOPB RoHS compliant and lead-free?
Yes, the /NOPB suffix in LM2574N-ADJ/NOPB explicitly denotes lead-free and RoHS-compliant packaging per Texas Instruments' product marking convention. The device uses matte tin lead finish and meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements for surface-mount assembly, though its DIP-8 through-hole form factor is exempt from reflow profile constraints.
LM2574N-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- 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:
- 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
LM2574N-ADJ/NOPB FAQ
1.How can I place an order for LM2574N-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2574N-ADJ/NOPB 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 LM2574N-ADJ/NOPB reliable?
The price and inventory of LM2574N-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2574N-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2574N-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2574N-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2574N-ADJ/NOPB?
LM2574N-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2574N-ADJ/NOPB 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 LM2574N-ADJ/NOPB?
For technical support, including LM2574N-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2574N-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2574N-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2574N-ADJ/NOPB 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 LM2574N-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2574N-ADJ/NOPB?
All LM2574N-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2574N-ADJ/NOPB, 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 LM2574N-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2574N-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2574N-ADJ/NOPB Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
