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Texas Instruments LM2674N-ADJ
- Part No.:
- LM2674N-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2674N-ADJ.pdf
- Description:
- IC REG BUCK ADJ 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,198
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Product details
Overview
LM2674N-ADJ from Texas Instruments is a monolithic 500 mA step-down (buck) DC-DC switching regulator in an 8-pin DIP package, featuring a 260 kHz fixed-frequency oscillator, 0.25 Ω DMOS output switch, and adjustable output voltage range of 1.21 V to 37 V. It delivers >90% efficiency, ±1.5% output voltage tolerance over line/load/temperature, and includes thermal shutdown, current limiting, and TTL-compatible shutdown with 50 μA standby current - used in industrial power supplies and embedded system pre-regulators.
For engineers reviewing the LM2674N-ADJ datasheet, LM2674N-ADJ pinout, LM2674N-ADJ application, or LM2674N-ADJ equivalent, key selection criteria include input voltage range (8–40 V), guaranteed 500 mA load capability, feedback reference voltage (1.21 V), RDS(ON) (0.25 Ω), and compatibility with standard off-the-shelf inductors and Schottky catch diodes.
Technical Context
The LM2674N-ADJ implements a synchronous-buck topology using an internal DMOS power switch and patented frequency compensation (U.S. Pat. Nos. 5,382,918 and 5,514,947). Its 260 kHz fixed-frequency oscillator enables predictable EMI behavior and simplifies filter design with standard inductor values.
Output voltage is set externally via a resistive divider connected to the FB pin, referenced to a precise 1.21 V internal bandgap. The ON/OFF pin provides TTL-level shutdown control, while the BOOST pin supports gate drive for the integrated switch; thermal shutdown and cycle-by-cycle current limiting ensure fault protection under overload or short-circuit conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Guaranteed 500 mA continuous load - sufficient for powering microcontrollers, sensors, and analog circuitry without external current boosting. |
| Input Voltage Range | 8 V to 40 V - supports wide-range industrial inputs including 12 V, 24 V, and 36 V rails with margin for transients. |
| Feedback Reference Voltage | 1.210 V ±1.8% - sets output accuracy baseline; enables precise programmable outputs from 1.21 V to 37 V using two external resistors. |
| Switch RDS(ON) | 0.25 Ω typical - minimizes conduction loss at full load, contributing to >90% peak efficiency (e.g., 90% at 12 VIN/5 VOUT/500 mA). |
| Switching Frequency | 260 kHz ±17% - balances size (smaller inductors/caps vs. lower frequencies) and efficiency (lower switching loss vs. higher frequencies). |
| Quiescent Current | 2.5 mA typical - enables low-noise operation in active regulation; drops to 50 μA in shutdown mode for battery-sensitive applications. |
| Thermal Resistance θJA | 95 °C/W (N package) - allows full 500 mA output without heatsink when mounted on ≥1 in² copper area. |
Pinout & Package
LM2674N-ADJ uses an 8-pin plastic dual in-line package (DIP), through-hole mount, with standard MO8A/N08E footprint. Pin spacing is 0.300 inch (7.62 mm), row-to-row pitch is 0.600 inch (15.24 mm).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts 8–40 V DC; requires local 22 μF tantalum bypass capacitor close to pin to suppress input ripple and transients. |
| 2 (GND) | Power Ground | Common return for input/output paths and IC substrate; must connect to low-impedance ground plane to minimize noise and thermal resistance. |
| 3 (FB) | Feedback Input | Senses output voltage via resistor divider; high-impedance (85 nA bias) node requiring shielded routing to avoid noise-induced regulation error. |
| 4 (ON/OFF) | Shutdown Control | TTL-compatible enable input; pulled internally to 7 V; <2 V disables regulator (50 μA IQ); >2.5 V enables normal operation. |
| 5 (BOOST) | Bootstrap Capacitor Connection | Connects to 0.01 μF ceramic capacitor between SW and BOOST to generate gate drive voltage for internal DMOS switch. |
| 6 (SW) | Switch Node | Drains internal DMOS switch; connects to inductor and catch diode anode; high dv/dt node requiring short, low-inductance PCB traces. |
| 7 (GND) | Power Ground (Second) | Dedicated ground return for switch node; must be tied to Pin 2 at single-point star ground near IC to reduce ground bounce. |
| 8 (VOUT) | Output Voltage Sense / Compensation | Not directly connected to output; used only in fixed-output variants; for LM2674N-ADJ, this pin is NC (no connection) per TI datasheet Figure 2 layout. |
Key Features
| Feature | Design Value |
|---|---|
| Patented Internal Frequency Compensation | Eliminates need for external compensation network - reduces BOM count and design iteration time for stable loop response across all operating conditions. |
| Adjustable Output Voltage Range | 1.21 V to 37 V via two external resistors - supports custom rail generation (e.g., 3.3 V, 15 V, 24 V) without changing IC, enabling single-part inventory for multiple designs. |
| Integrated 0.25 Ω DMOS Power Switch | Reduces external component count and PCB area versus controller-only solutions; eliminates gate driver design and MOSFET selection effort. |
| TTL-Compatible Shutdown | Enables seamless integration with microcontroller GPIO or system power sequencers; 50 μA standby current extends battery life in portable equipment. |
| Thermal Shutdown + Current Limit | Provides autonomous fault recovery: cycle-by-cycle current limit prevents switch damage during overload; thermal shutdown latches off until junction cools below 150 °C. |
Applications
| Industrial Power Supply | Embedded System Pre-Regulator |
|---|---|
|
Use Scenario: Converting unregulated 24 V DC field bus to stable 5 V for PLC I/O modules and sensor interfaces. IC Role / Device Role: Primary step-down regulator delivering 500 mA with high line/load regulation and transient immunity. Use Value: Maintains ±1.5% output accuracy across 8–40 V input variation and 0–500 mA load steps, reducing need for post-regulation LDOs. |
Use Scenario: Generating clean 3.3 V supply for ARM Cortex-M4 MCU and peripheral ICs from noisy 12 V vehicle battery rail. IC Role / Device Role: High-efficiency pre-regulator preceding low-noise LDOs to minimize heat dissipation and improve PSRR. Use Value: >90% efficiency at 500 mA reduces thermal load on PCB; 260 kHz switching avoids sensitive audio/RF bands. |
| Positive-to-Negative Converter | Test & Measurement Equipment Supply |
|
Use Scenario: Building isolated –5 V rail using LM2674N-ADJ in inverting buck-boost configuration for op-amp biasing. IC Role / Device Role: Core switching element controlling energy transfer to coupled inductor; configured with external diode and capacitor. Use Value: Leverages same 260 kHz oscillator and current-limited switch for predictable timing and safe start-up in non-standard topologies. |
Use Scenario: Providing stable, low-noise 15 V and –15 V dual rails for precision ADC drivers and analog front-ends in bench instruments. IC Role / Device Role: Adjustable-output buck stage generating 15 V from 28 V input; paired with inverting stage for negative rail. Use Value: 1.21 V reference tolerance ensures accurate programmability; thermal shutdown protects against overloads during calibration sequences. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574N-ADJ | Lower 500 mA rating, 52 kHz switching frequency, no BOOST pin - requires external bootstrap or P-channel switch. | Higher output ripple and larger magnetics required; less suitable for space-constrained designs needing compact filters. | Choose when cost sensitivity outweighs size/efficiency; verify thermal performance at full load due to lower efficiency (~75%). |
| MP1584EN-LF-Z | 3 A rating, 1.5 MHz switching, integrated BOOT diode, smaller SO-8 package - higher switching loss but enables sub-2 mm height designs. | Requires re-optimization of LC filter components; not pin-compatible; needs different PCB layout for high-frequency EMI control. | Prefer for new designs targeting higher current or miniaturization; avoid if legacy DIP footprint or 260 kHz EMI profile is mandatory. |
Compared with LM2674N-ADJ, LM2574N-ADJ trades efficiency and frequency for legacy compatibility and lower cost, while MP1584EN-LF-Z offers higher current and density at the expense of layout complexity and EMI filtering effort - LM2674N-ADJ remains optimal for proven, thermally robust 500 mA DIP-based power stages.
Availability
LM2674N-ADJ is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded power supply designs requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.
Supply support for LM2674N-ADJ 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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2674 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for ease-of-use in non-isolated DC-DC buck applications where minimal external components, predictable performance, and rugged fault protection are critical.
FAQ
What is the maximum input voltage rating for LM2674N-ADJ?
The absolute maximum input voltage for LM2674N-ADJ is 45 V, but the recommended operating range is 8 V to 40 V DC. Exceeding 40 V may compromise long-term reliability and thermal margin, especially at full 500 mA load. The device includes internal clamp structures, but sustained operation above 40 V is not characterized or guaranteed per TI SNVS007E datasheet Section 6.1.
Can LM2674N-ADJ be used in a buck-boost configuration?
Yes - LM2674N-ADJ can be configured as a positive-to-negative inverting buck-boost converter using standard application circuits shown in TI's AN-1187 and datasheet Figure 12. In this mode, it regulates negative output voltage (e.g., –5 V, –12 V) from a positive input, leveraging the same 260 kHz oscillator and current-limited switch, though efficiency and ripple performance differ from standard buck operation.
What is the purpose of the BOOST pin on LM2674N-ADJ?
The BOOST pin on LM2674N-ADJ connects to a 0.01 μF ceramic capacitor between SW and BOOST to generate a boosted gate drive voltage for the internal DMOS switch. This ensures full enhancement of the N-channel switch across the entire input range (8–40 V), maintaining low RDS(ON) and high efficiency - omitting this capacitor causes severe drop in output current capability and possible thermal failure.
Does LM2674N-ADJ require an external compensation network?
No - LM2674N-ADJ incorporates patented internal frequency compensation (U.S. Pat. Nos. 5,382,918 and 5,514,947), eliminating the need for external Type II or Type III compensation components. This simplifies design, improves stability across input voltage and load variations, and removes tuning iterations - only the feedback resistors (R1/R2) and basic input/output capacitors are required for functional operation.
How does the ON/OFF pin function on LM2674N-ADJ?
The ON/OFF pin on LM2674N-ADJ is TTL-compatible: pulling it below 0.8 V (typical) disables the regulator into 50 μA standby mode, while voltages above 2.0 V (typical) enable normal operation. The pin is internally pulled up to ~7 V, so leaving it open defaults to enabled state - no external pull-up is needed, making interface with microcontrollers or logic gates straightforward and low-power.
LM2674N-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 6.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 500mA
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2674N-ADJ FAQ
1.How can I place an order for LM2674N-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2674N-ADJ 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 LM2674N-ADJ reliable?
The price and inventory of LM2674N-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2674N-ADJ is usually 5 days.
3.What payment methods are accepted for LM2674N-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2674N-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2674N-ADJ?
LM2674N-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2674N-ADJ 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 LM2674N-ADJ?
For technical support, including LM2674N-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2674N-ADJ requirements.
6.How does Aetrix verify that LM2674N-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2674N-ADJ 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 LM2674N-ADJ meets industry standards.
7.What is the process for return or replacement of LM2674N-ADJ?
All LM2674N-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2674N-ADJ, 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 LM2674N-ADJ part is unused and in its original packaging.
Return procedure for LM2674N-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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