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Texas Instruments LM2678SDX-ADJ/NOPB
- Part No.:
- LM2678SDX-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2678SDX-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,714
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Product details
Overview
LM2678SDX-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator delivering up to 5 A output current with adjustable output voltage (1.2 V to 37 V), 260 kHz fixed-frequency operation, 120 mΩ internal DMOS switch, and ±2% output voltage tolerance over full line/load/temperature range. It serves as a high-efficiency (up to 92%) primary power conversion stage in industrial power supplies and battery-based systems.
For engineers reviewing the LM2678SDX-ADJ/NOPB datasheet, LM2678SDX-ADJ/NOPB pinout, LM2678SDX-ADJ/NOPB application, or LM2678SDX-ADJ/NOPB equivalent, key selection criteria include its 8 V–40 V input range, ON/OFF control interface, FB-based output programming, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and Schottky diodes for rapid design implementation.
Technical Context
The LM2678SDX-ADJ/NOPB integrates a high-side DMOS power switch controlled by a fixed 260 kHz PWM oscillator and error amplifier with feedback via the FB pin. Its internal architecture supports continuous conduction mode (CCM) operation with duty cycle directly proportional to VOUT/VIN, enabling stable regulation across wide input/output ratios.
It features dedicated bootstrapping (CB pin), thermally enhanced ground path through exposed DAP, and an ON/OFF pin with 1.4 V threshold and 50 µA standby current. Protection includes current limiting (6.1–8.3 A typical), thermal shutdown, and absolute maximum ratings covering −1 V to VIN on SW and 45 V on VIN.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5 A continuous - supports high-power loads without external pass devices. |
| Input Voltage Range | 8 V to 40 V - accommodates 12 V/24 V industrial rails and wide-range battery inputs. |
| Output Voltage Range | 1.2 V to 37 V (adjustable) - configured externally via resistor divider on FB pin. |
| Switching Frequency | 260 kHz (±11%) - enables use of compact magnetics and predictable EMI filtering. |
| RDS(ON) | 120 mΩ at TJ = 25°C - minimizes conduction loss and improves efficiency at high load currents. |
| Feedback Voltage | 1.21 V (±1.1%) - sets output accuracy; determines VOUT = 1.21 × (1 + R1/R2). |
| Standby Current | 50 µA - enables ultra-low-power shutdown for battery longevity in portable systems. |
| Operating Junction Temp | −40°C to +125°C - qualified for harsh industrial and automotive under-hood environments. |
Pinout & Package
LM2678SDX-ADJ/NOPB uses the KTW (TO-263-7) package: 10.1 mm × 15.24 mm thermally enhanced surface-mount outline with exposed DAP connected to GND for optimal heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain node of internal high-side DMOS FET; connects to inductor and cathode of external Schottky diode - carries high dv/dt switching waveform. |
| 2 (VIN) | Input supply | Main power input (8–40 V); requires low-ESR bypass capacitor placed adjacent to minimize ringing and ensure stable bias. |
| 3 (CB) | Bootstrap capacitor | Connects to SW via 100 nF ceramic capacitor to generate gate drive voltage > VIN for full FET enhancement. |
| 4 (GND) | Power ground | Primary return path for input/output capacitors and internal circuitry; must be tied to system ground and DAP for thermal/electrical integrity. |
| 5 (NC) | No connect | Internally unconnected; must remain floating - no routing or soldering required. |
| 6 (FB) | Feedback sense | High-impedance input (85 nA bias) monitoring output divider midpoint; sets regulated VOUT = 1.21 V × (1 + R1/R2). |
| 7 (ON/OFF) | Enable control | Logic-level input: ≥1.4 V enables regulation; ≤0.8 V disables with 50 µA quiescent draw - supports microcontroller-controlled power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120 mΩ DMOS switch | Eliminates need for external high-current MOSFET and driver, reducing BOM count and layout complexity. |
| Fixed 260 kHz oscillator | Enables consistent EMI profile and simplifies filter design versus variable-frequency controllers. |
| ±2% output tolerance | Guarantees tight regulation across temperature and load without post-production trimming. |
| Thermal shutdown & current limit | Protects against fault conditions without external sensing circuitry - self-recovering after fault removal. |
| WEBENCH® Power Designer support | Provides validated component selection, schematic generation, and performance simulation for rapid prototyping. |
| Exposed thermal pad (DAP) | Reduces θJA to 35°C/W (with 0.49 in² copper) - sustains 5 A output without heatsink in most PCB layouts. |
Applications
| Industrial PLC Power Supply | Battery-Powered Test Equipment |
|---|---|
Use Scenario: Provides stable 5 V or 12 V rail from 24 V DC bus in programmable logic controller backplanes with transient-heavy loads. IC Role / Device Role / Timing Role: Primary buck converter delivering regulated intermediate voltage to FPGA, I/O drivers, and communication interfaces. Use Value: 92% peak efficiency reduces thermal stress in enclosed cabinets; ON/OFF pin enables firmware-controlled power cycling during idle states. | Use Scenario: Generates 3.3 V or adjustable output from 9 V or 12 V Li-ion battery packs in handheld multimeters and signal analyzers. IC Role / Device Role / Timing Role: Main system regulator supplying microcontroller, ADC, and display subsystems with low-noise, tightly regulated power. Use Value: 50 µA shutdown current extends battery life between measurements; wide 8–40 V input handles fully charged and deeply discharged battery states. |
| Automotive Body Control Module | LED Driver Pre-regulator |
Use Scenario: Steps down 12 V vehicle battery (8–16 V nominal, up to 40 V load dump) to 5 V for MCU and CAN transceivers in door modules. IC Role / Device Role / Timing Role: Robust preregulator ensuring stable logic supply despite battery voltage fluctuations and cold-crank events. Use Value: −40°C to +125°C junction rating meets automotive AEC-Q100 ambient requirements; built-in current limit prevents damage during short-circuit faults. | Use Scenario: Supplies constant-current LED driver ICs with precisely regulated 5–24 V input, improving luminance consistency across varying input sources. IC Role / Device Role / Timing Role: High-efficiency pre-converter preceding linear or switching LED current sources to reduce thermal load. Use Value: Adjustable output allows matching driver IC headroom requirements; 260 kHz frequency avoids audible noise in sensitive lighting applications. |
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), wider VIN (4.5–40 V) | Limited to lower-power applications; less efficient at >3 A loads due to higher conduction loss. | Select when cost sensitivity outweighs current capability and efficiency needs. |
| TPS54560DGQR | 5 A, 100 V max input, 2.5–60 V input range, adjustable frequency (100–2500 kHz), integrated soft-start | Better suited for high-input-voltage or programmable-frequency designs; lacks TO-263 thermal performance at full load. | Choose for >40 V input or when frequency tuning is required for EMI compliance. |
Compared with LM2596SX-ADJ/NOPB and TPS54560DGQR, LM2678SDX-ADJ/NOPB delivers superior thermal performance in TO-263 packaging for sustained 5 A operation, maintains tighter output tolerance (±2% vs ±3%), and offers simpler external component requirements - making it optimal for cost-sensitive, high-reliability industrial buck converters where 8–40 V input and fixed 260 kHz operation are acceptable.
Availability
LM2678SDX-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial PLC power supplies, battery-powered test equipment, automotive body control modules, and LED driver pre-regulators requiring stable component supply and long-term production continuity.
Supply support for LM2678SDX-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 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 to simplify high-efficiency DC-DC buck regulator implementation using minimal external components and industry-standard passive parts.
FAQ
What is the maximum output current supported by the LM2678SDX-ADJ/NOPB?
The LM2678SDX-ADJ/NOPB is rated for continuous 5 A output current under recommended operating conditions (TJ ≤ 125°C, proper PCB thermal design). Peak current limit is 6.1–8.3 A depending on junction temperature, but sustained operation above 5 A requires careful thermal management using the exposed DAP and adequate copper area.
How do I set the output voltage for the LM2678SDX-ADJ/NOPB?
The LM2678SDX-ADJ/NOPB uses the FB pin to sense output voltage via an external resistor divider. Set VOUT = 1.21 V × (1 + R1/R2), where R2 connects from FB to GND and R1 from VOUT to FB. The 1.21 V reference has ±1.1% tolerance, so final output accuracy depends on resistor precision and layout stability.
Does the LM2678SDX-ADJ/NOPB require an external bootstrap capacitor?
Yes - the LM2678SDX-ADJ/NOPB requires a 100 nF ceramic capacitor connected between the CB pin and the SW pin. This capacitor provides the gate drive voltage boost needed to fully enhance the internal high-side DMOS switch; omission causes severe efficiency loss and potential device failure.
What thermal considerations apply to the LM2678SDX-ADJ/NOPB in TO-263 (KTW) package?
The LM2678SDX-ADJ/NOPB in KTW package relies on its exposed DAP (pin 4) for thermal conduction. With 0.4896 in² (3.6× package area) of 1 oz. copper, θJA is 35°C/W. For 5 A operation at 40 VIN/5 VOUT, junction temperature rise is ~70°C - requiring ambient ≤55°C or additional heatsinking for continuous full-load use.
Can the LM2678SDX-ADJ/NOPB be synchronized to an external clock?
No - the LM2678SDX-ADJ/NOPB uses an internal fixed-frequency 260 kHz oscillator with no external synchronization capability. Frequency variation is ±11% over temperature and supply; for precise timing or EMI reduction via frequency dithering, consider alternatives like TPS54560DGQR.
LM2678SDX-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)
LM2678SDX-ADJ/NOPB FAQ
1.How can I place an order for LM2678SDX-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678SDX-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 LM2678SDX-ADJ/NOPB reliable?
The price and inventory of LM2678SDX-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 LM2678SDX-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2678SDX-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678SDX-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2678SDX-ADJ/NOPB?
LM2678SDX-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678SDX-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 LM2678SDX-ADJ/NOPB?
For technical support, including LM2678SDX-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678SDX-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2678SDX-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2678SDX-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 LM2678SDX-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2678SDX-ADJ/NOPB?
All LM2678SDX-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2678SDX-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 LM2678SDX-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2678SDX-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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