My Inquiry
My Account
Texas Instruments LM2678SX-5.0
- Part No.:
- LM2678SX-5.0
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2678SX-5.0.pdf
- Description:
- IC REG BUCK 5V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:4,642
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2678SX-5.0 from Texas Instruments is a monolithic step-down (buck) DC/DC switching regulator delivering up to 5 A output current with fixed 5 V output, 8 V–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 LM2678SX-5.0 datasheet, LM2678SX-5.0 pinout, LM2678SX-5.0 application, or LM2678SX-5.0 equivalent, key selection criteria include its 5 A continuous load capability, 50 µA shutdown quiescent current, thermal shutdown protection, ON/OFF control interface, and compatibility with standard off-the-shelf inductors and Schottky diodes for rapid design implementation.
Technical Context
The LM2678SX-5.0 implements a voltage-mode PWM controller with a fixed 260 kHz oscillator and internal current-limit protection. Its DMOS high-side switch operates with 0.12 Ω typical RDS(ON) at 25°C, enabling >90% efficiency at full load under nominal conditions.
Feedback is internally configured for 5 V fixed output-pin 6 (FB) connects directly to VOUT, eliminating external resistors. The ON/OFF pin (pin 7) provides logic-level enable/disable control with 1.4 V threshold and 20 µA pull-up, supporting low-power standby states without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±2% over –40°C to 125°C junction temperature, 8–40 V input, 100 mA–5 A load |
| Max Output Current | 5 A continuous; current limit set to 6.1–8.3 A depending on temperature |
| Input Voltage Range | 8 V to 40 V DC - supports wide-range industrial and battery-derived inputs |
| Switching Frequency | 260 kHz ±11% - enables use of compact, standardized inductors and reduces EMI filtering burden |
| RDS(ON) | 0.12 Ω typical at 25°C - minimizes conduction loss and thermal rise at full load |
| Quiescent Current | 6 mA typical in active mode; 50 µA max in shutdown - enables low-power standby in battery systems |
| Efficiency | 84% typical at 12 VIN, 5 AOUT - achieved via low-RDS(ON) switch and optimized gate drive |
Pinout & Package
LM2678SX-5.0 is supplied in the KTW (TO-263-7) package: thermally enhanced 7-pin surface-mount variant with exposed DAP (die attach pad) tied to GND for improved heat dissipation. Package dimensions: 10.1 mm × 15.24 mm.
| 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 high-frequency loop inductance |
| 3 (CB) | Bootstrap capacitor | Connects to SW via 100 nF ceramic capacitor to generate gate drive voltage above VIN for full FET enhancement |
| 4 (GND) | Power ground | Primary return path for input/output capacitors and internal circuitry; must be connected to large copper area for thermal and noise control |
| 5 (NC) | No connect | Internally unconnected; electrically isolated - no routing or termination required |
| 6 (FB) | Feedback sense | Internally tied to 5 V reference; direct connection to output capacitor ensures precise regulation without external divider |
| 7 (ON/OFF) | Enable control | Logic-compatible input: ≥1.4 V enables regulation; ≤0.8 V disables with 50 µA standby draw; internal 20 µA pull-up simplifies interface |
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 5 V output configuration | Removes feedback resistor network, improving accuracy, stability, and production consistency vs adjustable variants |
| 260 kHz fixed-frequency PWM | Enables predictable EMI spectrum and consistent selection of low-cost, widely available inductors (e.g., Renco, Pulse, Coilcraft) |
| Thermal shutdown + current limiting | Provides autonomous fault protection during overload, short-circuit, or inadequate heatsinking - no external monitoring needed |
| 50 µA shutdown quiescent current | Supports energy-sensitive applications like battery-backed systems or always-on controllers requiring ultra-low standby power |
Applications
| Industrial Power Preregulator | Battery Charger Front-End |
|---|---|
Use Scenario: Preconditioning 24 V or 36 V battery bus to stable 5 V for downstream logic and communication ICs in motor drives or PLC modules. IC Role / Device Role / Timing Role: Primary buck converter providing regulated 5 V rail with high efficiency and thermal robustness across wide input transients. Use Value: Delivers 5 A continuously at >84% efficiency, reducing heat sink requirements and enabling compact board-level power architecture. | Use Scenario: Generating clean 5 V auxiliary supply from variable-input battery charger circuits (e.g., 12–40 V input during CC/CV stages). IC Role / Device Role / Timing Role: Fixed-output step-down regulator supplying isolated control logic, ADC references, and USB interface power. Use Value: Maintains ±2% output accuracy across full temperature and load range, ensuring reliable microcontroller and sensor operation. |
| Embedded System Main Rail | High-Current FPGA I/O Supply |
Use Scenario: Providing primary 5 V domain for ARM-based industrial controllers with multiple peripherals and Ethernet PHYs. IC Role / Device Role / Timing Role: High-current DC/DC converter operating in continuous conduction mode with fast transient response to dynamic CPU loads. Use Value: Achieves <100 µs load transient recovery (500 mA → 5 A), minimizing voltage droop and preventing logic glitches. | Use Scenario: Powering FPGA I/O banks requiring tightly regulated 5 V at up to 4 A peak current in test equipment or data acquisition systems. IC Role / Device Role / Timing Role: Efficient, thermally managed power stage with integrated current limit and thermal shutdown for safe operation under partial-load faults. Use Value: 0.12 Ω RDS(ON) limits power loss to <3 W at 5 A, enabling operation without forced air cooling in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-5.0 | Lower 3 A output rating; 150 kHz switching frequency; higher RDS(ON) (~0.22 Ω); TO-263-5 package | Suitable for lower-current designs (<3 A); less efficient at full load; requires larger inductor due to lower frequency | Select when cost sensitivity outweighs current/efficiency requirements and thermal margin is ample. |
| TPS54560B | Adjustable output (0.8–60 V); 5.5 A rating; 100–2500 kHz programmable frequency; integrated soft-start; smaller 8-pin SOIC package | Requires external feedback resistors; better suited for designs needing flexibility or tighter EMI control via frequency tuning | Choose when output voltage adjustability, programmable frequency, or enhanced protection features (UVLO, thermal foldback) are required. |
Compared with LM2678SX-5.0, LM2596S-5.0 offers lower cost but reduced current capability and efficiency, while TPS54560B provides greater design flexibility and integration at the expense of fixed-output simplicity and pinout compatibility.
Availability
LM2678SX-5.0 is available at Aetrix Electronics and suitable for industrial power preregulators, battery charger front-ends, and embedded system main rails requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2678SX-5.0 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 solutions.
The LM2678 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use, minimal external component count, and rapid time-to-market in non-isolated DC/DC buck applications up to 5 A.
FAQ
What is the maximum input voltage rating for the LM2678SX-5.0?
The LM2678SX-5.0 has an absolute maximum input voltage rating of 45 V, with recommended operating range from 8 V to 40 V DC. Exceeding 40 V during normal operation risks violating recommended conditions and may accelerate parametric drift or reduce reliability. The device includes internal protection against transient overvoltage, but sustained operation above 40 V is not supported per datasheet specifications.
Does the LM2678SX-5.0 require external feedback resistors to set the output voltage?
No, the LM2678SX-5.0 does not require external feedback resistors. As a fixed 5 V output variant, it contains internal precision feedback divider circuitry. Pin 6 (FB) must be connected directly to the output capacitor terminal to close the regulation loop - no external components are needed for voltage setting, simplifying layout and improving accuracy versus adjustable versions.
How does the ON/OFF pin function on the LM2678SX-5.0?
The ON/OFF pin (pin 7) of the LM2678SX-5.0 enables logic-level control: applying ≥1.4 V turns the regulator on, while ≤0.8 V forces shutdown with only 50 µA quiescent current. An internal 20 µA pull-up allows simple operation by leaving the pin floating for always-on use. The pin tolerates up to 6 V and includes a 7 V Zener clamp to ground, making it robust against overvoltage during system sequencing.
What thermal performance can be expected from the LM2678SX-5.0 in the KTW package?
In the KTW (TO-263-7) package with appropriate PCB copper area, the LM2678SX-5.0 achieves RθJA of 35°C/W (with 0.4896 in² copper) or 26°C/W (with 1.0064 in² copper). At 5 A output and 12 V input, typical power dissipation is ~3.2 W - resulting in ~85°C junction rise above ambient with 35°C/W, well within the –40°C to 125°C operating range when mounted on ≥0.5 in² 1 oz. copper.
Which external components are mandatory for basic operation of the LM2678SX-5.0?
Four external components are mandatory: (1) input capacitor (low-ESR, ≥100 µF) placed adjacent to VIN and GND pins, (2) output capacitor (low-ESR, ≥400 µF) connected directly to VOUT and GND, (3) power inductor (e.g., 10 µH, rated ≥6 A), and (4) Schottky catch diode (e.g., 60 V, ≥6 A, low forward voltage). The bootstrap capacitor (100 nF) between CB and SW is also required for gate drive functionality.
LM2678SX-5.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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)
LM2678SX-5.0 FAQ
1.How can I place an order for LM2678SX-5.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678SX-5.0 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 LM2678SX-5.0 reliable?
The price and inventory of LM2678SX-5.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2678SX-5.0 is usually 5 days.
3.What payment methods are accepted for LM2678SX-5.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678SX-5.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2678SX-5.0?
LM2678SX-5.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678SX-5.0 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 LM2678SX-5.0?
For technical support, including LM2678SX-5.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678SX-5.0 requirements.
6.How does Aetrix verify that LM2678SX-5.0 is sourced from the original manufacturer or authorized distributors?
All LM2678SX-5.0 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 LM2678SX-5.0 meets industry standards.
7.What is the process for return or replacement of LM2678SX-5.0?
All LM2678SX-5.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM2678SX-5.0, 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 LM2678SX-5.0 part is unused and in its original packaging.
Return procedure for LM2678SX-5.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2678SX-5.0 Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
