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Texas Instruments LM2674N-3.3
- Part No.:
- LM2674N-3.3
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2674N-3.3.pdf
- Description:
- IC REG BUCK 3.3V 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,512
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Product details
Overview
LM2674N-3.3 from Texas Instruments is a monolithic 500 mA step-down (buck) switching voltage regulator in an 8-pin DIP package, delivering a fixed 3.3 V output with ±1.5% tolerance over line and load, 260 kHz fixed-frequency operation, and >90% efficiency at 12 V input/500 mA load - used in industrial power supplies and embedded system pre-regulation.
For engineers reviewing the LM2674N-3.3 datasheet, LM2674N-3.3 pinout, LM2674N-3.3 application, or LM2674N-3.3 equivalent, key selection criteria include input voltage range (6.5–40 V), thermal resistance (95 °C/W), shutdown quiescent current (50 μA), RDS(ON) (0.25 Ω), and compatibility with standard off-the-shelf inductors and Schottky catch diodes.
Technical Context
The LM2674N-3.3 integrates a DMOS power switch, internal frequency compensation (Patents 5,382,918 & 5,514,947), and fixed 260 kHz oscillator to enable stable buck conversion without external compensation. Its feedback loop references a 1.21 V internal bandgap, enabling precise regulation across input voltages from 6.5 V to 40 V and load currents up to 500 mA.
Protection features include cycle-by-cycle current limiting (0.62–1.2 A threshold), thermal shutdown, and TTL-compatible ON/OFF control with 1.4 V turn-on threshold and 50 μA standby current. The device operates over −40 °C to +125 °C junction temperature and requires only five external components for full implementation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±1.5% over full line/load/temperature range - ensures stable logic supply for 3.3 V microcontrollers and FPGAs. |
| Max Output Current | 500 mA continuous - supports moderate-power digital subsystems without external current boosting. |
| Input Voltage Range | 6.5 V to 40 V - accommodates wide-input industrial rails, battery-backed systems, and automotive-derived supplies. |
| Switching Frequency | 260 kHz (±10%) - enables use of compact, low-cost 47–100 μH inductors and reduces EMI compared to lower-frequency alternatives. |
| RDS(ON) | 0.25 Ω typical - minimizes conduction loss and supports >90% efficiency at 12 V input/500 mA output. |
| Quiescent Current | 2.5 mA typical (active), 50 μA typical (shutdown) - enables low-power standby modes in always-on applications. |
| Thermal Resistance | 95 °C/W (Junction-to-Ambient, N package) - allows natural-convection cooling on standard PCB copper; no heatsink required below ~2 W dissipation. |
Pinout & Package
LM2674N-3.3 is housed in an 8-pin plastic dual in-line package (DIP), with through-hole mounting and industry-standard MO8A/N08E footprint. Thermal performance relies on PCB copper area surrounding pins 1, 4, 5, and 8.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts 6.5–40 V DC; requires local 22 μF tantalum bypass capacitor near pin to suppress transients. |
| 2 (GND) | Power Ground | Common return for input/output capacitors, inductor, and catch diode; must be low-impedance connection to minimize noise. |
| 3 (SW) | Switch Node | Drives external catch diode and inductor; high dv/dt node requiring short, direct routing to minimize EMI and ringing. |
| 4 (FB) | Feedback Input | Not connected for fixed 3.3 V version; internally tied to output divider - leave unconnected per datasheet. |
| 5 (ON/OFF) | Enable Control | TTL-compatible shutdown pin; pulled up internally to 7 V; drive ≤0.8 V to disable (50 μA standby). |
| 6 (BOOST) | Bootstrap Capacitor Terminal | Connects to 0.01 μF ceramic capacitor between SW and BOOST to gate-drive the internal DMOS switch fully. |
| 7 (GND) | Power Ground (Second) | Dedicated ground return for BOOST circuitry; tie directly to Pin 2 ground plane with minimal trace length. |
| 8 (VOUT) | Regulated Output | Delivers 3.3 V ±1.5%; requires 47–100 μF low-ESR output capacitor (e.g., Sprague 594D or AVX TPS series). |
Key Features
| Feature | Design Value |
|---|---|
| Patented Internal Compensation | Eliminates need for external compensation network - reduces design time and BOM count while ensuring stability across all operating conditions. |
| Standard Inductor Compatibility | Works with off-the-shelf 47–100 μH inductors from Schott, Renco, Pulse, and Coilcraft - avoids custom magnetics and accelerates prototyping. |
| Integrated Protection | Combines current limit, thermal shutdown, and safe-start sequencing - prevents damage during overload, short-circuit, or thermal runaway events. |
| Low Standby Current | 50 μA shutdown current enables energy-sensitive applications such as battery-backed monitoring circuits and remote sensors. |
| High Efficiency Architecture | DMOS switch + optimized gate drive delivers >90% efficiency at 12 V/500 mA - reduces heat generation and simplifies thermal management. |
Applications
| Industrial Power Supply | Embedded System Pre-Regulator |
|---|---|
Use Scenario: Providing clean 3.3 V rail from unregulated 24 V factory bus in PLC I/O modules. IC Role / Device Role / Timing Role: Primary DC-DC buck converter supplying power to ARM Cortex-M4 MCU and RS-485 transceivers. Use Value: Delivers 500 mA at >92% efficiency with no heatsink required, reducing board space and thermal derating concerns. | Use Scenario: Generating 3.3 V intermediate rail before LDO post-regulation in FPGA-based vision processing units. IC Role / Device Role / Timing Role: High-efficiency pre-regulator stepping down 12 V to 3.3 V, feeding low-noise linear regulators for core logic and I/O banks. Use Value: Minimizes power loss upstream of sensitive analog/RF sections, improving overall system thermal profile and PSRR. |
| Positive-to-Negative Converter | Automotive Body Control Module |
Use Scenario: Configured in inverting topology to generate −3.3 V bias for op-amp signal conditioning in sensor front-ends. IC Role / Device Role / Timing Role: Buck-derived inverting regulator using external diode and capacitor; leverages same 260 kHz oscillator and current limit. Use Value: Avoids dedicated inverting ICs; achieves regulated negative rail with proven layout guidelines and component selection tables. | Use Scenario: Powering 3.3 V CAN controller and EEPROM in under-hood body control unit with 9–16 V battery input. IC Role / Device Role / Timing Role: Primary switching regulator handling cold-crank (6.5 V) and load-dump (40 V) transients per ISO 7637-2. Use Value: Wide 6.5–40 V input range and integrated protection ensure reliable operation across automotive voltage extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574N-3.3 | Lower 500 mA rating, 52 kHz switching frequency, higher RDS(ON) (0.45 Ω), no internal compensation - requires external RC network. | Higher output ripple, larger filter components, less suitable for space-constrained designs. | Prefer LM2674N-3.3 when board area, efficiency, or design simplicity are critical. |
| TPS54302DDAR | 3 A rating, 2.5–6 V input, integrated high-side FET, 2.5 MHz switching, smaller SO-8 package - no DIP option. | Better for low-input-voltage, high-current, or ultra-compact applications; not drop-in compatible. | Choose TPS54302DDAR only if redesigning for surface-mount and higher current capability. |
Compared with LM2574N-3.3, LM2674N-3.3 offers 260 kHz operation for smaller magnetics and patented internal compensation for faster design cycles; versus TPS54302DDAR, it provides through-hole DIP packaging and wider 6.5–40 V input support - making it optimal for legacy industrial upgrades and ruggedized environments.
Availability
LM2674N-3.3 is available at Aetrix Electronics and suitable for industrial power supplies, embedded system pre-regulation, positive-to-negative conversion, and automotive body control modules requiring stable component supply and long-term manufacturability.
Supply support for LM2674N-3.3 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 focused on analog and embedded processing technologies, with broad portfolio coverage in power management, signal chain, and microcontrollers.
The LM2674 series belongs to TI's SIMPLE SWITCHER® family of easy-to-use DC-DC converters, designed specifically for engineers needing robust, high-efficiency buck regulation with minimal external components and fast time-to-market.
FAQ
What is the maximum input voltage rating for LM2674N-3.3?
The absolute maximum input voltage for LM2674N-3.3 is 45 V, but the recommended operating range is 6.5 V to 40 V per the Electrical Characteristics table. Exceeding 40 V risks violating guaranteed performance specs, especially under transient conditions like load dump. For automotive applications with ISO 7637-2 compliance, the 40 V upper limit ensures reliable operation during 12 V system surges.
Does LM2674N-3.3 require an external feedback resistor network?
No, LM2674N-3.3 does not require external feedback resistors. It is a fixed-output variant with internal resistor divider set to 3.3 V; the FB pin is unused and must remain unconnected. This simplifies layout and eliminates resistor tolerance errors - unlike the adjustable LM2674N-ADJ version, which requires two precision resistors to set VOUT.
What is the thermal resistance (θJA) of the LM2674N-3.3 package?
The LM2674N-3.3 in its 8-pin DIP (N) package has a junction-to-ambient thermal resistance (θJA) of 95 °C/W, measured with approximately 1 square inch of PCB copper surrounding the leads. This value assumes standard FR-4 board material and single-layer copper; adding thermal vias or increasing copper area lowers effective θJA, improving power handling capability of the LM2674N-3.3.
Can LM2674N-3.3 be used in discontinuous conduction mode (DCM)?
Yes, LM2674N-3.3 supports both continuous and discontinuous conduction modes depending on load, inductance, and input voltage. At light loads (<100 mA) with typical 47–100 μH inductors, it naturally transitions into DCM - reducing light-load quiescent current and improving efficiency below 10% load. The datasheet provides DCM waveforms and design guidance specific to LM2674N-3.3.
What type of catch diode is recommended for LM2674N-3.3?
A Schottky diode rated ≥3 A and ≥50 V is recommended for LM2674N-3.3, such as the IR 30WQ05F (3.3 A, 50 V). Its low forward voltage (≤0.5 V) and fast recovery minimize conduction loss and improve efficiency. The diode must be placed adjacent to the LM2674N-3.3 with short traces to reduce parasitic inductance - critical for stable switching and EMI control.
LM2674N-3.3 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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 6.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- 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-3.3 FAQ
1.How can I place an order for LM2674N-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2674N-3.3 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-3.3 reliable?
The price and inventory of LM2674N-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2674N-3.3 is usually 5 days.
3.What payment methods are accepted for LM2674N-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2674N-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2674N-3.3?
LM2674N-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2674N-3.3 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-3.3?
For technical support, including LM2674N-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2674N-3.3 requirements.
6.How does Aetrix verify that LM2674N-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2674N-3.3 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-3.3 meets industry standards.
7.What is the process for return or replacement of LM2674N-3.3?
All LM2674N-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2674N-3.3, 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-3.3 part is unused and in its original packaging.
Return procedure for LM2674N-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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