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Texas Instruments LM2678SDX-ADJ
- Part No.:
- LM2678SDX-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2678SDX-ADJ.pdf
- Description:
- IC REG BUCK ADJ 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,640
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Product details
Overview
LM2678SDX-ADJ from Texas Instruments is a monolithic step-down (buck) DC-DC voltage regulator with integrated 120 mΩ DMOS power switch, delivering up to 5A output current across an 8V–40V input range and adjustable 1.2V–37V output via external feedback resistors. It operates at fixed 260 kHz switching frequency and achieves up to 92% efficiency in optimized designs, targeting high-current industrial power rails and battery-charger pre-regulators.
For engineers reviewing the LM2678SDX-ADJ datasheet, LM2678SDX-ADJ pinout, LM2678SDX-ADJ application, or LM2678SDX-ADJ equivalent, key selection criteria include its ±2% output tolerance over line/load/temperature, 50 μA standby current in shutdown, thermal shutdown and cycle-by-cycle current limiting, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.
Technical Context
The LM2678SDX-ADJ implements a fixed-frequency PWM controller with internal 260 kHz oscillator and voltage-mode feedback architecture. Its error amplifier compares the resistor-divided output voltage against a precise 1.21 V reference (±2.3% over temperature), driving a pulse-width modulator that controls the integrated DMOS switch.
Thermal protection activates at ~160°C junction temperature, and current limiting triggers at 6.1–8.75 A (typ. 7 A), with frequency foldback under severe overload. The ON/OFF pin provides logic-level enable control with 0.8–2.0 V threshold and 50 μA shutdown quiescent current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Up to 5 A continuous load capability with proper thermal management |
| Input Voltage Range | 8 V to 40 V - supports wide-range industrial and battery-derived supplies |
| Output Voltage Range | 1.2 V to 37 V - set externally via FB pin and resistor divider |
| Feedback Reference | 1.21 V ±2.3% - defines output accuracy and stability baseline |
| Switching Frequency | 260 kHz ±11% - enables predictable EMI filtering and compact magnetics |
| Efficiency | Up to 92% - achieved using low RDS(on) (120 mΩ) integrated DMOS switch |
| Standby Current | 50 μA - enables low-power system sleep modes without external LDO |
Pinout & Package
VSON-14 (Package Number NHM0014A) with exposed die attach pad (DAP) for thermal enhancement; requires PCB ground connection via DAP and ≥12 vias to inner copper layers for optimal θJA = 29°C/W performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 2) | Main power input | Accepts 8–40 V unregulated supply; must be bypassed locally with ≥10 μF low-ESR capacitor |
| VSW (Pins 1 & 11) | Switch node | Drives external inductor; swings from VIN to ~−0.5 V during OFF time; requires Schottky catch diode |
| FB (Pin 6) | Feedback input | Connects to resistor divider; regulates output by comparing to 1.21 V internal reference |
| ON/OFF (Pin 7) | Enable control | Logic-compatible input: <0.8 V = shutdown (50 μA IQ); >2.0 V = active |
| GND (Pins 4, 5, 8, 9, 10, 12, 13, 14) | Power and signal ground | Multi-pin ground reduces impedance; DAP (Pin 9) must connect to PCB ground plane |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120 mΩ DMOS switch | Eliminates need for external high-side MOSFET and gate driver, reducing BOM count and layout complexity |
| Fixed 260 kHz oscillator | Enables consistent EMI profile and simplifies filter design versus variable-frequency alternatives |
| ±2% output tolerance over full conditions | Meets tight regulation requirements for downstream analog or digital circuitry without post-regulation |
| Thermal shutdown + current limiting | Provides autonomous fault protection without external monitoring circuitry |
| 50 μA shutdown quiescent current | Supports battery-powered systems requiring ultra-low standby power |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
Use Scenario: Providing stable 15 V/3 A bias rail for gate drivers and isolated ADCs in servo amplifier modules. IC Role / Device Role / Timing Role: Primary buck regulator converting 24 V bus to intermediate rail; operates continuously at 85°C ambient. Use Value: Delivers 5 A peak current headroom and maintains ±2% regulation despite 10% input ripple and 2 A load transients. | Use Scenario: Generating 3.3 V/4 A core supply for FPGA-based baseband processing units in remote radio heads. IC Role / Device Role / Timing Role: High-efficiency pre-regulator feeding low-noise LDOs; synchronized to system clock via external sync not supported. Use Value: Achieves 90% efficiency at 12 V input, minimizing heat buildup in sealed outdoor enclosures. |
| Battery Charger Pre-Regulator | Test & Measurement Equipment |
Use Scenario: Stepping down 36 V LiFePO₄ pack voltage to 12 V for charging circuitry in portable EVSE units. IC Role / Device Role / Timing Role: Constant-voltage stage regulator before CC/CV battery management IC; handles 4 A continuous load. Use Value: Maintains regulation across full 8–40 V input range and survives automotive load-dump transients up to 45 V. | Use Scenario: Supplying 5 V/5 A for analog front-end signal conditioning and microcontroller subsystems in portable oscilloscopes. IC Role / Device Role / Timing Role: Main system power converter; enabled/disabled via microcontroller GPIO for power sequencing. Use Value: Enables <50 μA deep-sleep mode while preserving fast wake-up (<100 μs) due to internal reference retention. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596SX-ADJ/NOPB | 3 A max output, 150 kHz switching, higher RDS(on) (220 mΩ), no frequency foldback | Lower cost for ≤3 A loads; less efficient at high current; limited thermal robustness | Select when budget constraints outweigh 5 A requirement and efficiency is secondary |
| TPS54560DGRT | 5 A, 60 V input, 2.5–60 V output, 2.2 MHz switching, integrated soft-start and UVLO | Wider input range and higher frequency allow smaller magnetics; more complex compensation | Prefer for new designs needing >40 V input or space-constrained layouts where 2.2 MHz enables sub-10 mm² solution size |
Compared with LM2678SDX-ADJ, LM2596SX-ADJ/NOPB offers lower cost but sacrifices 40% peak current capability and thermal margin, while TPS54560DGRT extends input voltage and switching frequency at the expense of increased design complexity and reduced pin compatibility.
Availability
LM2678SDX-ADJ is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, battery charger pre-regulators, and test & measurement equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2678SDX-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 LM2678 series belongs to TI's SIMPLE SWITCHER® family-designed specifically for ease-of-use in non-isolated DC-DC buck applications where minimal external components, predictable performance, and robust fault protection are prioritized over ultra-high density or programmability.
FAQ
What is the maximum output current capability of the LM2678SDX-ADJ under typical operating conditions?
The LM2678SDX-ADJ delivers up to 5 A continuous output current when properly heatsinked on a PCB with ≥12 vias to inner ground layers and using recommended external components (e.g., 10 μH inductor, 400 μF low-ESR output capacitor). Derating applies above 85°C ambient; full 5 A is ensured at TJ ≤ 125°C with θJA ≤ 29°C/W.
Does the LM2678SDX-ADJ support synchronization to an external clock?
No, the LM2678SDX-ADJ does not support external clock synchronization. It uses an internal fixed-frequency 260 kHz oscillator with ±11% tolerance. For designs requiring synchronized switching (e.g., multi-rail systems), consider alternatives like the TPS54560DGRT which includes SYNC input functionality.
What is the minimum output voltage achievable with the LM2678SDX-ADJ?
The LM2678SDX-ADJ supports a minimum output voltage of 1.2 V, set by its internal 1.21 V feedback reference voltage and external resistor divider. Output voltages below 1.2 V are not supported, as the FB pin cannot regulate below the reference threshold. For sub-1.2 V outputs, a different regulator architecture (e.g., current-mode buck with lower VREF) is required.
How does the ON/OFF pin function on the LM2678SDX-ADJ?
The ON/OFF pin (Pin 7) provides logic-level enable control: pulling it below 0.8 V places LM2678SDX-ADJ in shutdown mode with 50 μA quiescent current, while driving it above 2.0 V enables normal operation. An internal 20 μA pull-up current source allows direct connection to microcontroller GPIO without external biasing; clamping diodes protect against overvoltage up to 6 V absolute maximum.
Can the LM2678SDX-ADJ be used with ceramic output capacitors only?
Yes, the LM2678SDX-ADJ is compatible with ceramic output capacitors, provided total ESR remains within stability guidelines (typically 5–15 mΩ for 400 μF equivalent). However, ceramic-only solutions may require careful attention to capacitance value and layout to avoid subharmonic oscillation; TI recommends verifying loop stability using the method outlined in Application Note AN-1187, especially when using <100 μF ceramic banks.
LM2678SDX-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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)
LM2678SDX-ADJ FAQ
1.How can I place an order for LM2678SDX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678SDX-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 LM2678SDX-ADJ reliable?
The price and inventory of LM2678SDX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2678SDX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2678SDX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678SDX-ADJ transactions.
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4.How is shipping managed for LM2678SDX-ADJ?
LM2678SDX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678SDX-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 LM2678SDX-ADJ?
For technical support, including LM2678SDX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678SDX-ADJ requirements.
6.How does Aetrix verify that LM2678SDX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2678SDX-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 LM2678SDX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2678SDX-ADJ?
All LM2678SDX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2678SDX-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 LM2678SDX-ADJ part is unused and in its original packaging.
Return procedure for LM2678SDX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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