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Texas Instruments LM2678SD-ADJ/NOPB
- Part No.:
- LM2678SD-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2678SD-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:590
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Product details
Overview
LM2678SD-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator IC delivering up to 5 A output current, supporting adjustable output voltages from 1.2 V to 37 V, with 260 kHz fixed-frequency operation and ±2% output voltage tolerance over full line/load/temperature range.
For engineers reviewing the LM2678SD-ADJ/NOPB datasheet, LM2678SD-ADJ/NOPB pinout, LM2678SD-ADJ/NOPB application, or LM2678SD-ADJ/NOPB equivalent, key selection criteria include its 8 V–40 V input range, 120 mΩ internal DMOS switch, 50 µA standby current, thermal shutdown, and ON/OFF control interface for system-level power sequencing.
Technical Context
The LM2678SD-ADJ/NOPB implements a fixed-frequency pulse-width modulation (PWM) controller with an integrated high-side DMOS power switch, operating at 260 kHz ±11% to enable compact external magnetics and filtering. Its feedback loop uses a precision 1.21 V reference (VFB = 1.186–1.234 V) sensed at the FB pin to regulate output via external resistor divider.
It supports active mode (ON/OFF ≥1.4 V) and shutdown mode (ON/OFF ≤0.8 V), drawing only 50 µA quiescent current in shutdown. Internal protection includes current limiting (6.1–8.3 A), thermal shutdown, and under-voltage lockout - all functional across –40°C to +125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Up to 5 A continuous load capability enables single-stage conversion for mid-power industrial and embedded systems. |
| Input Voltage Range | 8 V to 40 V DC supports wide-input applications including 12 V/24 V battery systems and unregulated industrial rails. |
| Output Voltage Range | Adjustable 1.2 V to 37 V via external resistor divider - supports custom rail generation without redesigning core regulator. |
| Switch RDS(on) | 120 mΩ typical at TJ = 25°C minimizes conduction loss and enables >90% efficiency at full load (e.g., 92% at 12 VIN/5 VOUT/5 A). |
| Oscillator Frequency | 260 kHz fixed frequency simplifies EMI filtering and allows use of standard off-the-shelf inductors (e.g., 10 µH) with predictable ripple current. |
| Feedback Reference | 1.21 V ±1.2% (1.174–1.246 V) at FB pin enables precise output setting with <±2% total output tolerance over line, load, and temperature. |
| Standby Current | 50 µA max at TJ = 25°C ensures ultra-low power consumption during system sleep or standby states. |
Pinout & Package
LM2678SD-ADJ/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad (DAP), measuring 10.1 mm × 15.24 mm, optimized for high-current thermal dissipation on PCB copper planes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch Output | Drain node of internal high-side DMOS FET; connects directly to inductor and Schottky catch diode cathode - carries high dv/dt switching waveform. |
| 2 (VIN) | Input Supply | Main power input (8–40 V); must be bypassed with low-ESR capacitor placed adjacent to pin to minimize high-frequency ringing and supply impedance. |
| 3 (CB) | Bootstrap Capacitor | Connects to SW via 100 nF ceramic capacitor to generate gate drive voltage >VIN for full enhancement of internal FET. |
| 4 (GND) | Power Ground | Primary return path for input/output capacitors and thermal pad (DAP); requires low-inductance connection to PCB ground plane. |
| 5 (NC) | No Connect | Internally unconnected; must remain floating - no routing or soldering permitted. |
| 6 (FB) | Feedback Input | Senses output voltage via external resistor divider; 85 nA bias current enables high-impedance dividers without significant error. |
| 7 (ON/OFF) | Enable Control | Logic-level input: ≥1.4 V enables regulation; ≤0.8 V disables output and reduces quiescent current to 50 µA. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120 mΩ DMOS Switch | Eliminates need for external high-side MOSFET and driver, reducing BOM count and layout complexity while maintaining >90% efficiency at 5 A. |
| Fixed 260 kHz Oscillator | Enables consistent EMI profile and predictable inductor sizing - avoids variable-frequency jitter and simplifies compliance testing. |
| ±2% Output Voltage Tolerance | Guaranteed accuracy over full operating range (–40°C to +125°C, 8–40 VIN, 100 mA–5 A) eliminates need for post-production trimming in most applications. |
| Thermal Shutdown & Current Limit | Protects against fault conditions without external circuitry: automatic recovery after cooldown and foldback current limiting prevent thermal runaway. |
| WEBENCH® Power Designer Support | Provides validated component selection, efficiency simulation, thermal modeling, and schematic generation - accelerates design from concept to prototype. |
Applications
| Industrial Motor Drive Power Supply | Programmable Logic Controller (PLC) I/O Module |
|---|---|
Use Scenario: Provides isolated 5 V or 12 V auxiliary rail from 24 V DC bus to power microcontrollers, analog front-ends, and digital isolators in motor control cabinets. IC Role / Device Role / Timing Role: Primary buck regulator delivering stable, high-current DC output with fast transient response to handle burst loads from sensor sampling and communication bursts. Use Value: 5 A capability and 260 kHz switching allow compact 10 µH inductor + 400 µF output capacitor solution meeting IEC 61000-4-2/4-4 immunity requirements. | Use Scenario: Generates configurable 3.3 V or 5 V logic supply for FPGA-based I/O modules requiring tight voltage regulation and low noise across wide ambient temperatures. IC Role / Device Role / Timing Role: Adjustable-output buck converter enabling flexible rail configuration per module variant without changing PCB layout or BOM. Use Value: ±2% output tolerance and 1.21 V reference ensure reliable FPGA core voltage margining; ON/OFF pin enables synchronized power-up sequencing with backplane controller. |
| Battery-Powered Test Equipment | Automotive Aftermarket Diagnostic Tool |
Use Scenario: Steps down 12 V lead-acid battery voltage to regulated 3.3 V for MCU, display, and USB interface in portable multimeters and oscilloscopes. IC Role / Device Role / Timing Role: High-efficiency preregulator preceding LDOs, minimizing heat buildup and extending battery runtime during extended measurements. Use Value: 92% peak efficiency at 5 A and 50 µA shutdown current extend operational time between charges; wide 8–40 V input accommodates cranking transients. | Use Scenario: Powers OBD-II interface electronics from vehicle 12 V system, surviving load dump (up to 40 V) and cold-crank (down to 6 V) events. IC Role / Device Role / Timing Role: Robust primary DC-DC stage with built-in overvoltage/overcurrent/thermal protection - replaces discrete protection circuits. Use Value: Absolute maximum input rating of 45 V and –40°C to +125°C operation ensure reliability in under-hood environments; TO-263 package provides mechanical ruggedness and thermal margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596T-ADJ/NOPB | 3 A output current, 150 kHz switching, higher RDS(on) (220 mΩ), wider VIN (4–40 V), lower cost. | Limited to ≤3 A loads; less efficient at high current; larger inductor required due to lower frequency. | Select when budget-constrained and load current ≤3 A; not suitable for 5 A continuous duty. |
| TPS54560QDGQRQ1 | 5 A, 60 V max input, 2.5–60 V input range, 100% duty cycle capability, AEC-Q100 qualified. | Automotive-grade qualification, enhanced ESD (±4 kV HBM), integrated soft-start, higher cost. | Select for automotive safety-critical systems requiring qualification and extended input range; over-spec for industrial non-automotive use. |
Compared with LM2596T-ADJ/NOPB, LM2678SD-ADJ/NOPB delivers 67% higher output current and 10% higher efficiency at full load, justifying its use in thermally constrained 5 A designs; versus TPS54560QDGQRQ1, it offers lower system cost and simpler layout but lacks automotive qualification and 100% duty cycle support.
Availability
LM2678SD-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial motor drives, programmable logic controllers, battery-powered test equipment, and automotive diagnostic tools requiring stable component supply and long-term production continuity.
Supply support for LM2678SD-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 is a global semiconductor leader designing analog, embedded processing, and connectivity technologies for industrial, automotive, and personal electronics markets.
The LM2678 series belongs to TI's SIMPLE SWITCHER® power converter family - engineered for ease-of-use in non-isolated DC-DC buck applications where high efficiency, minimal external components, and robust protection are prioritized over ultra-high switching frequencies or digital control.
FAQ
What is the maximum output current supported by the LM2678SD-ADJ/NOPB?
The LM2678SD-ADJ/NOPB supports up to 5 A of continuous output current under recommended operating conditions (TJ ≤ 125°C, adequate PCB copper area). Its internal current limit is specified from 5.75 A to 8.75 A depending on temperature, providing headroom for transient peaks. Thermal performance depends heavily on PCB layout - the TO-263 package requires proper DAP grounding and thermal copper to sustain full-load operation.
Does the LM2678SD-ADJ/NOPB require an external bootstrap capacitor?
Yes, the LM2678SD-ADJ/NOPB requires a 100 nF ceramic capacitor connected between the CB pin and the SW pin to provide gate drive voltage for the internal high-side DMOS switch. This bootstrap network ensures full enhancement of the FET, minimizing RDS(on) and maximizing efficiency. The capacitor must be placed close to the IC with short, low-inductance traces to maintain stability during switching transitions.
What is the feedback reference voltage of the LM2678SD-ADJ/NOPB?
The LM2678SD-ADJ/NOPB has a precision internal feedback reference voltage of 1.21 V, with a guaranteed range of 1.174 V to 1.246 V across –40°C to +125°C junction temperature. This reference is used at the FB pin to set output voltage via an external resistor divider (R1/R2), where VOUT = 1.21 V × (1 + R1/R2). Bias current into FB is only 85 nA, enabling high-resistance dividers without significant error.
Can the LM2678SD-ADJ/NOPB operate with an input voltage below 8 V?
No - the LM2678SD-ADJ/NOPB has a minimum recommended input voltage of 8 V per its absolute operating conditions. Below this, the internal bias circuitry may not function reliably, and the DMOS switch cannot be fully enhanced due to insufficient gate drive margin. Attempting operation below 8 V risks unstable regulation, increased dropout, or complete failure to start. For sub-8 V inputs, consider alternatives like the LM2596 or TPS5430.
How does the ON/OFF pin function on the LM2678SD-ADJ/NOPB?
The ON/OFF pin (Pin 7) provides logic-level enable control for the LM2678SD-ADJ/NOPB: applying ≥1.4 V enables regulation, while ≤0.8 V forces shutdown with only 50 µA standby current. The pin features an internal ~20 µA pull-up current source and a 7 V Zener clamp. It can be driven directly by microcontroller GPIO or open-collected transistor outputs - no external pull-up is required unless driving from high-impedance sources.
LM2678SD-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 37V
- 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:
- 14-VSON (5x6)
LM2678SD-ADJ/NOPB FAQ
1.How can I place an order for LM2678SD-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678SD-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 LM2678SD-ADJ/NOPB reliable?
The price and inventory of LM2678SD-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 LM2678SD-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2678SD-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678SD-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2678SD-ADJ/NOPB?
LM2678SD-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678SD-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 LM2678SD-ADJ/NOPB?
For technical support, including LM2678SD-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678SD-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2678SD-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2678SD-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 LM2678SD-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2678SD-ADJ/NOPB?
All LM2678SD-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2678SD-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 LM2678SD-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2678SD-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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