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Texas Instruments LM2678S-5.0/NOPB
- Part No.:
- LM2678S-5.0/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2678S-5.0/NOPB.pdf
- Description:
- IC REG BUCK 5V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,748
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Product details
Overview
LM2678S-5.0/NOPB from Texas Instruments is a monolithic step-down (buck) switching voltage regulator delivering up to 5 A output current with fixed 5 V output, 8–40 V input range, 260 kHz fixed-frequency operation, and ±2% output voltage tolerance over full line/load/temperature. It integrates a 120 mΩ DMOS high-side switch and supports efficient system preregulation in industrial power supplies.
For engineers reviewing the LM2678S-5.0/NOPB datasheet, LM2678S-5.0/NOPB pinout, LM2678S-5.0/NOPB application, or LM2678S-5.0/NOPB equivalent, key selection criteria include thermal performance in TO-263-7 package, ON/OFF control interface, feedback configuration for fixed-output use, and compatibility with standard off-the-shelf inductors and Schottky diodes.
Technical Context
The LM2678S-5.0/NOPB implements a fixed-frequency PWM buck controller with internal 260 kHz oscillator and integrated 120 mΩ DMOS high-side switch. Its feedback loop uses direct connection to output (no external divider) for 5 V fixed operation, enabling stable regulation across –40°C to 125°C junction temperature.
Functional modes include active regulation (ON/OFF ≥ 1.4 V) and shutdown (ON/OFF ≤ 0.8 V), drawing only 50 µA standby current. Protection features include thermal shutdown, cycle-by-cycle current limiting (6.1–8.3 A), and built-in boot-strap capacitor drive for high-side gate enhancement.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±2% over full line, load, and temperature (–40°C to 125°C) |
| Input Voltage Range | 8 V to 40 V - supports wide-input industrial and battery-derived supplies |
| Max Output Current | 5 A continuous - enables single-regulator solutions for mid-power systems |
| Switching Frequency | 260 kHz ±11% - enables use of compact, standardized inductors and reduces EMI filtering burden |
| Efficiency | Up to 84% at 12 VIN/5 VOUT/5 A - achieved via low RDS(on) (0.12 Ω) DMOS switch |
| Standby Current | 50 µA typical at shutdown - minimizes system-level quiescent power in always-on applications |
| Thermal Shutdown | Integrated protection - prevents damage during overload or poor heatsinking conditions |
Pinout & Package
LM2678S-5.0/NOPB is supplied in the KTW (TO-263-7) thermally enhanced surface-mount package (10.1 mm × 15.24 mm), featuring an exposed thermal pad (DAP) connected internally to GND for improved heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | High-side DMOS drain node - connects to inductor and cathode of external Schottky diode; switches between VIN and ~–0.5 V |
| 2 (VIN) | Input supply | Main power input (8–40 V); requires low-ESR bypass capacitor placed adjacent to pin |
| 3 (CB) | Bootstrap capacitor | Connects 100 nF ceramic capacitor to SW pin to drive high-side gate above VIN for full enhancement |
| 4 (GND) | Power ground | Primary return path for input/output capacitors and IC ground; must be tied to DAP and system ground plane |
| 5 (NC) | No connect | Internally unconnected - leave floating; no routing or soldering required |
| 6 (FB) | Feedback input | Direct connection to 5 V output (fixed version); internal resistor divider sets regulation point - no external components needed |
| 7 (ON/OFF) | Enable control | Logic-level input: ≥1.4 V = active regulation, ≤0.8 V = shutdown (50 µA IQ) |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120 mΩ DMOS switch | Enables high-efficiency (>84%) 5 A buck conversion without external MOSFET or driver complexity |
| Fixed 5 V output configuration | Eliminates external feedback resistors - simplifies layout, improves accuracy, and reduces BOM count |
| 260 kHz fixed-frequency PWM | Allows predictable EMI spectrum and consistent use of industry-standard off-the-shelf inductors |
| ON/OFF logic control with 50 µA shutdown | Supports system-level power sequencing and ultra-low-power sleep states without auxiliary circuitry |
| Thermal shutdown + current limit | Provides autonomous fault protection under overload, short-circuit, or inadequate heatsinking conditions |
Applications
| Industrial Power Supply | Battery-Powered Equipment |
|---|---|
Use Scenario: 24 V DC bus converted to regulated 5 V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary step-down regulator supplying logic and analog circuitry with tight voltage stability. Use Value: ±2% output tolerance ensures reliable microcontroller and ADC operation across temperature and load transients. | Use Scenario: 12–36 V LiFePO₄ battery pack powering portable test instrumentation with low-noise analog front-end. IC Role / Device Role / Timing Role: High-efficiency preregulator preceding LDOs to minimize thermal stress and extend runtime. Use Value: 84% efficiency at 5 A reduces heat generation and enables compact thermal design in sealed enclosures. |
| Automated Test Equipment | Embedded Control Unit |
Use Scenario: Rack-mounted ATE subsystem requiring stable 5 V at up to 5 A for FPGA, memory, and interface ICs. IC Role / Device Role / Timing Role: Main DC-DC converter with ON/OFF control synchronized to system power-up sequence. Use Value: 50 µA shutdown current enables deep-sleep mode while retaining fast wake-up capability via logic-level enable. | Use Scenario: Engine control unit (ECU) deriving 5 V from vehicle battery (9–16 V nominal, up to 40 V load dump). IC Role / Device Role / Timing Role: Robust primary regulator tolerant of automotive voltage transients and wide ambient temperatures. Use Value: –40°C to 125°C operating range and integrated thermal/current protection ensure reliability in under-hood environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678T-5.0/NOPB | Same electrical specs; TO-220-7 package with vertical leadform and higher RθJA (65°C/W unheatsinked) | Preferred where through-hole mounting or manual heatsinking is used; less suitable for high-density SMT layouts | Select when mechanical constraints favor TO-220 or when board-level airflow allows adequate passive cooling |
| LM2596S-5.0 | 3 A max output, 150 kHz switching, no ON/OFF pin; similar 5 V fixed output and TO-263-5 package | Suitable for lower-current applications where 50 µA shutdown and 260 kHz EMI profile are not required | Choose for cost-sensitive designs with <3 A loads and relaxed transient response or thermal requirements |
Compared with LM2678T-5.0/NOPB, the LM2678S-5.0/NOPB offers superior thermal performance in SMT form factor; versus LM2596S-5.0, it delivers 67% higher current, faster transient response, and integrated enable control - critical for programmable power sequencing.
Availability
LM2678S-5.0/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery-powered instrumentation, and automotive embedded control requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2678S-5.0/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 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 LM2678 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use in non-isolated DC-DC buck applications, minimizing external component count while maintaining high efficiency and robust protection.
FAQ
What is the maximum input voltage rating for the LM2678S-5.0/NOPB?
The LM2678S-5.0/NOPB has an absolute maximum input voltage rating of 45 V, with recommended operating range specified from 8 V to 40 V. Exceeding 40 V continuously may trigger overvoltage stress or reduce long-term reliability, though brief transients up to 45 V are tolerated per absolute maximum ratings. The LM2678S-5.0/NOPB is commonly used in automotive and industrial systems where load-dump events reach 40 V.
Does the LM2678S-5.0/NOPB require external feedback resistors?
No - the LM2678S-5.0/NOPB is the fixed 5 V output variant and contains internal feedback resistors. Pin 6 (FB) must be connected directly to the output capacitor for regulation; no external divider is needed. This eliminates tuning error and improves accuracy compared to adjustable versions. The LM2678S-5.0/NOPB achieves ±2% output tolerance without user calibration.
How does the ON/OFF pin function on the LM2678S-5.0/NOPB?
The ON/OFF pin (Pin 7) enables logic-level control: applying ≥1.4 V activates regulation, while ≤0.8 V places the LM2678S-5.0/NOPB in shutdown mode with 50 µA standby current. The pin features an internal 20 µA pull-up and 7 V Zener clamp. Floating the pin defaults to ON. This interface allows seamless integration with microcontrollers or power sequencers without level-shifting circuitry.
What package type is used for the LM2678S-5.0/NOPB?
The LM2678S-5.0/NOPB is packaged in the KTW (TO-263-7) thermally enhanced surface-mount outline, measuring 10.1 mm × 15.24 mm with an exposed thermal pad (DAP) electrically and thermally connected to GND. This package provides significantly lower thermal resistance than TO-220 alternatives and is optimized for PCB copper area-based heatsinking in high-power density designs.
Can the LM2678S-5.0/NOPB drive a 5 A load continuously?
Yes - the LM2678S-5.0/NOPB is rated for continuous 5 A output current under proper thermal conditions. Achieving this requires adequate PCB copper area (≥1.0 in² of 2 oz. copper connected to the DAP), minimal trace resistance, and ambient temperature ≤85°C. At 12 VIN/5 VOUT, efficiency reaches 84%, limiting power dissipation to ~4.5 W - manageable with the KTW package's thermal design.
LM2678S-5.0/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 5A
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-7)
LM2678S-5.0/NOPB FAQ
1.How can I place an order for LM2678S-5.0/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678S-5.0/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 LM2678S-5.0/NOPB reliable?
The price and inventory of LM2678S-5.0/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2678S-5.0/NOPB is usually 5 days.
3.What payment methods are accepted for LM2678S-5.0/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678S-5.0/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2678S-5.0/NOPB?
LM2678S-5.0/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678S-5.0/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 LM2678S-5.0/NOPB?
For technical support, including LM2678S-5.0/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678S-5.0/NOPB requirements.
6.How does Aetrix verify that LM2678S-5.0/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2678S-5.0/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 LM2678S-5.0/NOPB meets industry standards.
7.What is the process for return or replacement of LM2678S-5.0/NOPB?
All LM2678S-5.0/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2678S-5.0/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 LM2678S-5.0/NOPB part is unused and in its original packaging.
Return procedure for LM2678S-5.0/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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