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Texas Instruments LM2678T-5.0
- Part No.:
- LM2678T-5.0
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2678T-5.0.pdf
- Description:
- IC REG BUCK 5V 5A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:1,171
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Product details
Overview
LM2678T-5.0 from Texas Instruments is a monolithic step-down (buck) switching voltage regulator with fixed 5 V output, 5 A load capability, 8–40 V input range, 260 kHz fixed-frequency operation, and ±2% output tolerance over full line/load/temperature. It integrates a 120 mΩ DMOS high-side switch and supports ON/OFF control for low-power standby mode in industrial power supplies.
For engineers reviewing the LM2678T-5.0 datasheet, LM2678T-5.0 pinout, LM2678T-5.0 application, or LM2678T-5.0 equivalent, key selection criteria include input voltage range compatibility, thermal performance in TO-263 package, efficiency at 5 A load, feedback configuration for fixed-output use, and shutdown quiescent current specification.
Technical Context
The LM2678T-5.0 implements a fixed-frequency PWM buck controller with internal 260 kHz oscillator and integrated 120 mΩ DMOS high-side switch. Its feedback loop uses direct connection to output (no external divider) for 5 V regulation, enabling stable operation with minimal external components.
It features active thermal shutdown, cycle-by-cycle current limiting (6.1–8.3 A), and ON/OFF pin control with 1.4 V threshold and 50 µA standby current. The device operates across –40°C to +125°C junction temperature and requires bootstrap capacitor (CB) connection between pins 1 and 3 for gate drive enhancement.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±2% over –40°C to 125°C, 100 mA–5 A load, 8–40 V input - ensures precise regulation without external resistors. |
| Max Output Current | 5 A continuous - supports high-current industrial and embedded power rails without external current boosting. |
| Input Voltage Range | 8 V to 40 V - compatible with 12 V/24 V industrial buses and wide-range DC inputs. |
| Switching Frequency | 260 kHz ±11% - enables use of compact off-the-shelf inductors and reduces EMI compared to lower frequencies. |
| RDS(ON) | 0.12 Ω typical at 25°C - minimizes conduction loss and supports >90% efficiency at full load. |
| Standby Current | 50 µA at TJ = 25°C - enables ultra-low-power shutdown for battery-backed or energy-sensitive systems. |
| Thermal Shutdown | Integrated - protects against sustained overload or poor heatsinking in enclosed environments. |
Pinout & Package
LM2678T-5.0 is supplied in KTW (TO-263-7) package: thermally enhanced surface-mount variant with exposed DAP (die attach pad) soldered to PCB ground plane for optimal heat dissipation. Dimensions: 10.1 mm × 15.24 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain node of internal DMOS FET; connects to inductor and Schottky diode cathode - must be routed with low-inductance layout. |
| 2 (IN) | Input supply | High-current VIN path feeding internal circuitry and switch; requires local 100 nF ceramic + bulk capacitor within 5 mm. |
| 3 (CB) | Bootstrap capacitor | Connects to SW pin via 100 nF capacitor to enable full gate drive above VIN - critical for RDS(ON) performance. |
| 4 (GND) | Power ground | Main return path for IN, SW, and FB; must tie directly to thermal pad and system ground plane. |
| 5 (NC) | No connect | Internally unconnected - leave floating or tie to GND per layout best practice; no electrical function. |
| 6 (FB) | Feedback input | Direct connection to 5 V output (no resistor divider) - sets regulation point using internal reference and amplifier. |
| 7 (ON/OFF) | Enable control | Logic-level input: ≥1.4 V = ON, ≤0.8 V = OFF; draws only 20 µA bias current when active. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120 mΩ DMOS switch | Eliminates need for external MOSFET and driver, reducing BOM count and board area in 5 A buck designs. |
| Fixed 5 V output with ±2% tolerance | Guarantees compliance with 5 V logic and analog subsystem requirements without calibration or trimming. |
| 260 kHz fixed-frequency PWM | Enables predictable EMI filtering and consistent inductor sizing across production units. |
| 50 µA shutdown current | Supports low-power modes in portable or always-on equipment where standby consumption is constrained. |
| Thermal shutdown + current limit | Provides autonomous fault protection during transient overloads or inadequate heatsinking - no external monitoring needed. |
Applications
| Industrial Power Supply | Battery Charger Pre-regulator |
|---|---|
Use Scenario: Converting 24 V DC bus to regulated 5 V for PLC I/O modules and sensor interfaces in factory automation cabinets. IC Role / Device Role / Timing Role: Primary step-down regulator delivering clean, high-current 5 V rail with thermal robustness under ambient temperatures up to 70°C. Use Value: Delivers 5 A continuously with >84% efficiency at 12 V input, minimizing heat buildup in densely packed enclosures. | Use Scenario: Providing stable 5 V intermediate rail for multi-stage Li-ion charger ICs requiring precise input voltage prior to CC/CV stage. IC Role / Device Role / Timing Role: Efficient preregulator stepping down variable adapter or solar input (12–36 V) to fixed 5 V before linear post-regulation. Use Value: Reduces power dissipation in downstream LDOs by lowering their dropout voltage requirement, improving overall charging efficiency. |
| Embedded System Main Rail | Test Equipment Power Module |
Use Scenario: Generating main 5 V supply for ARM-based edge controllers with mixed-signal peripherals and Ethernet PHYs. IC Role / Device Role / Timing Role: Core power converter supplying processor, memory, and interface ICs with tight load transient response and low ripple. Use Value: Achieves <100 mV output deviation during 500 mA → 5 A load steps (100 µs recovery), maintaining digital logic stability. | Use Scenario: Modular 5 V/5 A power stage in benchtop multimeters or signal generators requiring field-replaceable, high-reliability DC-DC sections. IC Role / Device Role / Timing Role: Standalone, thermally managed power module with ON/OFF control synchronized to instrument sleep/wake cycles. Use Value: Enables remote power cycling via microcontroller GPIO, reducing system idle power to <1 mW with 50 µA standby draw. |
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-5.0 | Lower 3 A rating, 150 kHz switching frequency, higher RDS(ON) (0.22 Ω), no thermal pad in TO-220 variant. | Suitable for <3 A loads with relaxed size/efficiency requirements; less effective at high ambient temperatures. | Select if cost sensitivity outweighs current/thermal needs and board space allows larger inductor. |
| TPS54560BQDDARQ1 | Automotive-grade 60 V input, 5 A synchronous buck, 2.2 MHz operation, integrated high-/low-side FETs, adjustable output. | Requires external feedback resistors and offers wider VIN but higher complexity and cost; not pin-compatible. | Choose for automotive or high-input-voltage designs needing AEC-Q100 qualification and higher frequency operation. |
Compared with LM2596T-5.0, the LM2678T-5.0 delivers 67% higher current capacity and superior thermal performance in TO-263; versus TPS54560BQDDARQ1, it offers simpler fixed-output implementation and lower system cost, though without synchronous rectification or extended input voltage range.
Availability
LM2678T-5.0 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-term manufacturability, and proven thermal reliability in TO-263 packaging.
Supply support for LM2678T-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 ICs.
The LM2678 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use, minimal external component count, and robust performance in industrial and commercial DC-DC applications without requiring advanced power design expertise.
FAQ
What is the maximum input voltage rating for the LM2678T-5.0?
The LM2678T-5.0 has an absolute maximum input voltage rating of 45 V, with recommended operating range from 8 V to 40 V. Exceeding 40 V during normal operation risks violating recommended conditions and may reduce long-term reliability; transient spikes beyond 40 V must remain below 45 V and be limited in duration per datasheet stress limits.
Does the LM2678T-5.0 require an external feedback resistor network?
No, the LM2678T-5.0 does not require external feedback resistors. As a fixed 5 V output variant, it uses internal precision resistors to set the feedback reference; pin 6 (FB) must be connected directly to the output capacitor for regulation - no external divider is needed or supported.
How is thermal performance affected by PCB layout for the LM2678T-5.0?
Thermal performance of the LM2678T-5.0 depends critically on PCB copper area connected to its exposed DAP (pin 4 ground pad). With 0.4896 in² (12.4 cm²) of 1 oz. copper, RθJA drops to 35°C/W; insufficient copper or missing thermal vias increases junction temperature, potentially triggering thermal shutdown at 5 A load in ambient >60°C.
Can the LM2678T-5.0 be used in discontinuous conduction mode (DCM)?
Yes, the LM2678T-5.0 operates in both continuous and discontinuous conduction modes depending on load. At light loads (<500 mA), it naturally transitions to DCM, reducing switching losses and improving light-load efficiency - confirmed by datasheet waveforms and typical characteristics curves.
What is the purpose of the CB pin on the LM2678T-5.0?
The CB (bootstrap capacitor) pin on the LM2678T-5.0 connects to the switch node (pin 1) via a 100 nF capacitor to generate a gate drive voltage above VIN, ensuring full enhancement of the internal DMOS high-side switch. Without proper CB connection, RDS(ON) rises significantly, degrading efficiency and causing thermal overload.
LM2678T-5.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-7 Formed Leads
- Packaging:
- Tube
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2678T-5.0 FAQ
1.How can I place an order for LM2678T-5.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678T-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 LM2678T-5.0 reliable?
The price and inventory of LM2678T-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 LM2678T-5.0 is usually 5 days.
3.What payment methods are accepted for LM2678T-5.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678T-5.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2678T-5.0?
LM2678T-5.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678T-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 LM2678T-5.0?
For technical support, including LM2678T-5.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678T-5.0 requirements.
6.How does Aetrix verify that LM2678T-5.0 is sourced from the original manufacturer or authorized distributors?
All LM2678T-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 LM2678T-5.0 meets industry standards.
7.What is the process for return or replacement of LM2678T-5.0?
All LM2678T-5.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM2678T-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 LM2678T-5.0 part is unused and in its original packaging.
Return procedure for LM2678T-5.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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