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Texas Instruments LM2679SX-5.0/NOPB
- Part No.:
- LM2679SX-5.0/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2679SX-5.0/NOPB.pdf
- Description:
- IC REG BUCK 5V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,330
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Product details
Overview
LM2679SX-5.0/NOPB from Texas Instruments is a monolithic 5-A step-down (buck) DC/DC voltage regulator with fixed 5-V output, 8–40 V input range, 260-kHz fixed-frequency PWM control, and resistor-programmable current limit (5.5–7.6 A typical at RADJ = 5.6 kΩ). It integrates a 120-mΩ DMOS high-side switch and supports soft-start via external capacitor, targeting industrial power supplies and battery chargers.
For engineers reviewing the LM2679SX-5.0/NOPB datasheet, LM2679SX-5.0/NOPB pinout, LM2679SX-5.0/NOPB application, or LM2679SX-5.0/NOPB equivalent, key selection criteria include its ±2% output tolerance over line/load/temperature, thermal shutdown protection, adjustable peak current limit, TO-263-7 package thermal performance (RθJA = 26°C/W with 7.4× paddle copper), and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.
Technical Context
The LM2679SX-5.0/NOPB implements a fixed-frequency (260 kHz) current-mode PWM controller driving an integrated 120-mΩ DMOS high-side switch. Its feedback loop senses output voltage directly at the FB pin (shorted to VOUT for fixed versions), enabling ±2% regulation across –40°C to 125°C junction temperature.
Current limiting is set by an external resistor (RADJ) connected between Current Adjust (pin 5) and GND, establishing ICL = 37,125 / RADJ (A); for 5.6 kΩ, ICL = 6.6 A typical. Soft-start is controlled by a capacitor from SS (pin 7) to GND, ramping duty cycle to limit inrush current during startup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V, ±2% tolerance over full line (8–40 V), load (100 mA–5 A), and temperature (–40°C to 125°C) |
| Max Output Current | 5 A continuous, limited by internal thermal shutdown and programmable peak switch current (5.5–7.6 A) |
| Input Voltage Range | 8 V to 40 V DC - supports wide industrial and automotive battery-derived inputs |
| Switching Frequency | 260 kHz fixed (±11%) - enables use of compact magnetics and reduces EMI fundamental frequency |
| Efficiency | Up to 92% (at 12 V IN, 5 A OUT for 12-V version); 84% typical for LM2679SX-5.0/NOPB at 12 V IN, 5 A OUT |
| ON-Resistance | 120 mΩ (typical at TJ = 25°C) - minimizes conduction loss in high-current buck stage |
| Quiescent Current | 6 mA max - ensures low no-load power draw in always-on systems |
Pinout & Package
LM2679SX-5.0/NOPB is packaged in TO-263-7 (KTW), a surface-mount thermally enhanced variant of DDPAK with exposed thermal pad (DAP) soldered to PCB copper for low RθJA (26°C/W with 7.4× paddle area).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch Output | Drain node of internal DMOS FET; connects to inductor and Schottky diode cathode - high dv/dt node requiring short layout |
| 2 (VIN) | Input Supply | Main power input (8–40 V); must be bypassed with low-ESR ceramic capacitors placed adjacent to pin |
| 3 (CB) | Bootstrap Capacitor | Connects 0.01 µF capacitor to SW pin to generate gate drive voltage > VIN for full FET enhancement |
| 4 (GND) | Power Ground | Common return for input/output capacitors, thermal pad, and internal circuitry - requires low-inductance plane |
| 5 (IADJ) | Current Limit Adjust | Resistor-to-GND sets peak switch current: ICL = 37,125 / RADJ (e.g., 5.6 kΩ → 6.6 A) |
| 6 (FB) | Feedback Input | Direct connection to 5-V output (fixed version); internal resistive divider sets regulation point - no external divider needed |
| 7 (SS) | Soft-Start | Capacitor-to-GND controls output voltage ramp time; floating disables soft-start |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120-mΩ DMOS switch | Enables 5-A output without external MOSFET; reduces BOM count and layout complexity |
| Resistor-programmable current limit | Allows precise fault-current tailoring (3–7 A range) without redesign - protects load and IC under short-circuit |
| 260-kHz fixed-frequency operation | Permits consistent EMI filtering design and use of standardized, low-cost inductors from Renco, Pulse, Coilcraft |
| Soft-start with external capacitor | Prevents input surge current at turn-on - critical for systems with limited upstream current capacity or hot-swap requirements |
| Thermal shutdown protection | Automatically disables switching above safe junction temperature (125°C), preventing permanent damage during overload |
Applications
| Industrial Power Supply | Battery Charger |
|---|---|
Use Scenario: 24-V rail conversion to stable 5-V logic supply for PLC I/O modules operating in ambient temperatures up to 70°C. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 5-V/5-A output with ±2% accuracy and thermal derating capability. Use Value: Eliminates need for external current-sense amplifier or discrete MOSFET driver; achieves 84% efficiency at full load with minimal external components. |
Use Scenario: On-board charging circuit for 12-V sealed lead-acid battery banks in telecom backup systems. IC Role / Device Role / Timing Role: Constant-voltage stage regulating charge voltage to 5.0 V with programmable current limit to match battery acceptance profile. Use Value: Resistor-adjustable current limit (via RADJ) allows precise charge current setting without firmware or DAC; thermal shutdown prevents battery overheat during fault conditions. |
| Embedded System Preregulator | Test Equipment Power Module |
Use Scenario: Pre-regulation stage feeding linear regulators in FPGA-based instrumentation where low noise and tight transient response are required. IC Role / Device Role / Timing Role: High-efficiency intermediate converter reducing 24-V input to 5-V before LDO post-regulation. Use Value: 260-kHz switching frequency enables effective LC filtering ahead of LDO; soft-start prevents LDO input overshoot during system power-up. |
Use Scenario: Modular 5-V/5-A power module in automated test equipment requiring field-replaceable, drop-in power stages. IC Role / Device Role / Timing Role: Self-contained buck regulator with integrated switch, current limit, and thermal protection - no external driver or sense circuitry needed. Use Value: TO-263-7 package with exposed thermal pad supports conduction-cooled mounting; pin-compatible replacement path within LM2679 family simplifies inventory management. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678SX-5.0/NOPB | Lower 3-A output rating; identical 260-kHz frequency, TO-263-7 package, and feature set (soft-start, current limit, thermal shutdown) | Suitable only for ≤3-A loads; lacks headroom for future current scaling or transient peaks beyond 3 A | Select when 3-A maximum load is confirmed and cost reduction is prioritized over margin. |
| TPS54560DGQ | Higher 60-V input rating, 500-kHz switching, integrated compensation; requires external MOSFETs; different pinout and control architecture | Supports wider input range (3.5–60 V) and faster transient response but increases design complexity and component count | Choose for designs needing >40-V input or higher switching frequency; not a drop-in replacement. |
Compared with LM2678SX-5.0/NOPB, the LM2679SX-5.0/NOPB delivers 66% higher current capacity in the same footprint; versus TPS54560DGQ, it offers simpler implementation with integrated switch and fixed-frequency control, at the expense of input voltage range and programmability.
Availability
LM2679SX-5.0/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery chargers, embedded preregulators, and test equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2679SX-5.0/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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies with broad industrial, automotive, and communications applications.
The LM2679 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically to simplify high-current DC/DC buck converter implementation using minimal external components while maintaining robust thermal and fault protection.
FAQ
What is the maximum input voltage rating for LM2679SX-5.0/NOPB?
The absolute maximum input voltage for LM2679SX-5.0/NOPB is 45 V DC, but the recommended operating range is strictly 8 V to 40 V. Operation above 40 V risks exceeding safe operating area limits and may trigger internal protection or cause premature failure. Always maintain ≥1-V margin below 45 V in worst-case transients.
How do I configure the current limit on LM2679SX-5.0/NOPB?
Connect a resistor (RADJ) between the Current Adjust pin (pin 5) and GND. The peak switch current is calculated as ICL = 37,125 / RADJ (in ohms), yielding 6.6 A typical with 5.6 kΩ. Use precision 1% metal-film resistors and verify actual current limit with oscilloscope measurement of inductor peak current under short-circuit test.
Does LM2679SX-5.0/NOPB require an external feedback resistor divider?
No. LM2679SX-5.0/NOPB is a fixed-output variant: its internal feedback divider is factory-trimmed for 5.0 V. Pin 6 (FB) must be connected directly to the output capacitor's positive terminal - no external resistors are needed or permitted for voltage setting.
What thermal performance can be expected from LM2679SX-5.0/NOPB in TO-263-7 package?
In the KTW (TO-263-7) package with 7.4× die attach paddle copper area, LM2679SX-5.0/NOPB achieves RθJA = 26°C/W. At 5-A load and 25°C ambient, junction temperature rise is ~130°C - well within the 125°C max rating only with adequate copper area and airflow. Derate output current above 85°C ambient per datasheet thermal curves.
Can LM2679SX-5.0/NOPB operate without a soft-start capacitor?
Yes. Leaving the SS pin (pin 7) unconnected disables soft-start, causing immediate full-duty-cycle startup. This may induce high inrush current into input capacitors and downstream circuits. TI recommends a 1-nF capacitor to ground for controlled 1–2 ms ramp unless fast turn-on is explicitly required and inrush is managed externally.
LM2679SX-5.0/NOPB 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:
- Active
- 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)
LM2679SX-5.0/NOPB FAQ
1.How can I place an order for LM2679SX-5.0/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679SX-5.0/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 LM2679SX-5.0/NOPB reliable?
The price and inventory of LM2679SX-5.0/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2679SX-5.0/NOPB is usually 5 days.
3.What payment methods are accepted for LM2679SX-5.0/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679SX-5.0/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679SX-5.0/NOPB?
LM2679SX-5.0/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679SX-5.0/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 LM2679SX-5.0/NOPB?
For technical support, including LM2679SX-5.0/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679SX-5.0/NOPB requirements.
6.How does Aetrix verify that LM2679SX-5.0/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2679SX-5.0/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 LM2679SX-5.0/NOPB meets industry standards.
7.What is the process for return or replacement of LM2679SX-5.0/NOPB?
All LM2679SX-5.0/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679SX-5.0/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 LM2679SX-5.0/NOPB part is unused and in its original packaging.
Return procedure for LM2679SX-5.0/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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