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Texas Instruments LM2678SD-12/NOPB
- Part No.:
- LM2678SD-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2678SD-12/NOPB.pdf
- Description:
- IC REG BUCK 12V 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,250
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Product details
Overview
LM2678SD-12/NOPB from Texas Instruments is a monolithic step-down (buck) switching regulator IC delivering up to 5 A output current with fixed 12 V output, 8–40 V input range, and 260 kHz fixed-frequency operation. It integrates a 120 mΩ DMOS high-side switch, supports ON/OFF control, and achieves up to 92% efficiency at 24 VIN/5 AOUT, targeting industrial power conversion and battery charger pre-regulation.
For engineers reviewing the LM2678SD-12/NOPB datasheet, LM2678SD-12/NOPB pinout, LM2678SD-12/NOPB application, or LM2678SD-12/NOPB equivalent, key selection criteria include verified 12 V ±2% output tolerance over –40°C to 125°C, 50 µA standby current in shutdown, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and Schottky diodes.
Technical Context
The LM2678SD-12/NOPB implements a voltage-mode PWM controller with a fixed 260 kHz oscillator and internal error amplifier driving a high-side DMOS switch. Its feedback loop uses a direct connection from FB pin to output for fixed-voltage regulation-no external resistor divider required. The device operates in continuous conduction mode under full-load conditions and includes cycle-by-cycle current limiting and thermal shutdown.
Control logic centers on the ON/OFF pin: ≥1.4 V enables switching and regulation; ≤0.8 V forces shutdown with 50 µA quiescent draw. The CB pin supplies bootstrapped gate drive to the internal MOSFET, requiring a 100 nF ceramic capacitor tied to the switch node (pin 1) to sustain full enhancement of the 120 mΩ RDS(ON) switch across temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±2% over full line/load/temperature (–40°C to 125°C), eliminating need for external feedback resistors. |
| Input Voltage Range | 8 V to 40 V DC-supports wide-range industrial inputs, automotive battery systems, and universal AC/DC front-ends. |
| Max Output Current | 5 A continuous-enables single-chip solutions for mid-power applications without external current boosting. |
| Switch RDS(ON) | 0.12 Ω typical at 25°C-minimizes conduction loss and enables >92% peak efficiency at 24 VIN/5 AOUT. |
| Standby Current | 50 µA at TJ = 25°C when ON/OFF pin = 0 V-reduces system-level power loss during idle or sleep modes. |
| Oscillator Frequency | 260 kHz ±11%-enables use of compact, low-cost inductors and reduces EMI compared to higher-frequency alternatives. |
| Thermal Protection | Integrated thermal shutdown with automatic recovery-prevents damage during overload or poor heatsinking without external circuitry. |
Pinout & Package
LM2678SD-12/NOPB is supplied in the KTW (TO-263-7) package: 10.1 mm × 15.24 mm thermally enhanced surface-mount outline with exposed DAP (die attach paddle) connected to GND for optimal thermal performance. The 7-pin configuration supports high-current routing and PCB copper area integration.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain node of internal high-side DMOS FET; connects directly to inductor and cathode of external Schottky diode-requires low-inductance layout to minimize ringing. |
| 2 (VIN) | Input supply | Main power input (8–40 V); must be bypassed with low-ESR capacitor placed adjacent to pin to suppress high-frequency transients. |
| 3 (CB) | Bootstrap capacitor | Connects to SW node 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 thermal paddle; requires solid copper pour and multiple vias to inner ground planes. |
| 5 (NC) | No connect | Internally unconnected-must remain floating; no routing or soldering permitted. |
| 6 (FB) | Feedback sense | Direct connection to 12 V output (fixed version); internal resistor divider sets regulation point-no external components needed. |
| 7 (ON/OFF) | Enable control | Logic-level enable: ≥1.4 V = active regulation; ≤0.8 V = shutdown with 50 µA IQ; internal 20 µA pull-up simplifies interface. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120 mΩ DMOS switch | Eliminates external MOSFET and driver, reducing BOM count and layout complexity while maintaining 5 A capability. |
| Fixed 12 V output with ±2% tolerance | Guarantees precise regulation across temperature and load without trimming or calibration-ideal for stable downstream rail generation. |
| 260 kHz fixed-frequency PWM | Enables predictable EMI filtering and consistent inductor sizing; avoids frequency jitter that complicates compliance testing. |
| ON/OFF pin with 50 µA shutdown | Supports system-level power sequencing and low-power states without auxiliary control circuitry or external LDOs. |
| Thermal shutdown + current limit | Provides autonomous fault protection under overload, short-circuit, or inadequate heatsinking-no external sensing or latch required. |
Applications
| Industrial Power Supply | Battery Charger Pre-regulator |
|---|---|
Use Scenario: Converting 24 V DC bus to regulated 12 V for PLC I/O modules, motor drivers, and sensor interfaces in factory automation. IC Role / Device Role / Timing Role: Primary buck converter delivering 5 A continuous output with tight line/load regulation and thermal robustness. Use Value: Replaces discrete switcher designs with fewer components, achieving >92% efficiency and eliminating manual compensation tuning. | Use Scenario: Stepping down variable-input DC (e.g., solar array or rectified AC) to stable 12 V before linear charging stages for lead-acid or LiFePO4 batteries. IC Role / Device Role / Timing Role: High-efficiency preregulator ensuring constant voltage feed to downstream CC/CV charge controllers. Use Value: Reduces heat dissipation versus linear preregulators and maintains regulation across wide input swings (8–40 V). |
| Embedded System Main Rail | Test Equipment Power Module |
Use Scenario: Generating 12 V main supply for FPGA-based data acquisition units, edge AI inference modules, and ruggedized field computers. IC Role / Device Role / Timing Role: Single-chip power solution with integrated protection, supporting extended temperature operation (–40°C to 125°C). Use Value: Delivers stable 12 V ±2% under dynamic load steps while enabling compact board area via TO-263 thermal design. | Use Scenario: Providing clean, well-regulated 12 V for benchtop instruments such as multimeters, oscilloscope analog front-ends, and signal generators. IC Role / Device Role / Timing Role: Low-noise, high-reliability DC-DC stage where long-term stability and low standby draw are critical. Use Value: Achieves 50 µA shutdown current and ±2% output accuracy-reducing calibration drift and extending instrument uptime. |
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-12/NOPB | Same electrical specs but in NDZ (TO-220-7) package; higher RθJA (65°C/W vs. 35°C/W for KTW) limits max power in compact layouts. | Preferred for through-hole prototyping or low-volume assemblies where heatsink mounting is straightforward. | Select when mechanical mounting constraints favor TO-220 or when existing tooling supports vertical heatsink attachment. |
| TPS54560BQPWPRQ1 | Automotive-grade 60 V input, 5 A buck with adjustable frequency (100–2500 kHz), but requires external feedback resistors and has higher quiescent current (145 µA). | Suitable for harsh-environment vehicles or systems needing programmable switching frequency for EMI optimization. | Choose only if AEC-Q100 qualification, wider input range, or frequency flexibility outweighs added component count and reduced efficiency at 12 VOUT. |
Compared with LM2678T-12/NOPB, the LM2678SD-12/NOPB offers superior thermal performance in space-constrained SMT designs; versus TPS54560BQPWPRQ1, it delivers simpler fixed-output implementation and lower standby current-but lacks automotive qualification and frequency adjustability.
Availability
LM2678SD-12/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charger pre-regulators, and embedded system main rails requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for LM2678SD-12/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 delivering robust 5 A performance across industrial temperature ranges.
FAQ
What is the maximum input voltage rating for the LM2678SD-12/NOPB?
The absolute maximum input voltage for the LM2678SD-12/NOPB is 45 V, but the recommended operating range is 8 V to 40 V DC. Operation above 40 V risks exceeding safe operating area limits and may trigger internal protection circuits. For reliable long-term use, maintain input within the 8–40 V window specified in Section 5.3 of the datasheet.
Does the LM2678SD-12/NOPB require external feedback resistors to set its output voltage?
No-the LM2678SD-12/NOPB is the fixed 12 V version of the LM2678 family and contains an internal resistor divider network. Pin 6 (FB) must be connected directly to the output capacitor to close the regulation loop; no external resistors are needed or permitted for this variant.
How does the ON/OFF pin function on the LM2678SD-12/NOPB?
The ON/OFF pin (pin 7) enables or disables regulation: applying ≥1.4 V activates the device, while ≤0.8 V places LM2678SD-12/NOPB into shutdown mode drawing only 50 µA. An internal 20 µA pull-up allows simple open-drain control; no external pull-up is required unless interfacing with low-voltage logic.
What package type is used for the LM2678SD-12/NOPB, and why does it matter thermally?
The LM2678SD-12/NOPB uses the KTW (TO-263-7) package with an exposed thermal pad (DAP) tied to GND. This construction achieves RθJA ≈ 35°C/W with adequate PCB copper area-significantly better than the TO-220 version-making it essential for sustained 5 A operation in compact, surface-mount industrial designs.
Can the LM2678SD-12/NOPB be used with ceramic output capacitors?
Yes-LM2678SD-12/NOPB supports ceramic output capacitors, but total capacitance and ESR must meet stability requirements. TI recommends ≥400 µF total output capacitance with ESR ≤13 mΩ; using multiple parallel ceramics helps achieve both targets while minimizing ripple. Always verify loop stability with actual layout parasitics.
LM2678SD-12/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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 15V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- 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:
- 14-VSON (5x6)
LM2678SD-12/NOPB FAQ
1.How can I place an order for LM2678SD-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678SD-12/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-12/NOPB reliable?
The price and inventory of LM2678SD-12/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-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2678SD-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678SD-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2678SD-12/NOPB?
LM2678SD-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678SD-12/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-12/NOPB?
For technical support, including LM2678SD-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678SD-12/NOPB requirements.
6.How does Aetrix verify that LM2678SD-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2678SD-12/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-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2678SD-12/NOPB?
All LM2678SD-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2678SD-12/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-12/NOPB part is unused and in its original packaging.
Return procedure for LM2678SD-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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