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Texas Instruments LM2679SDX-3.3/NOPB
- Part No.:
- LM2679SDX-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2679SDX-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,755
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Product details
Overview
LM2679SDX-3.3/NOPB from Texas Instruments is a monolithic 5-A step-down (buck) DC/DC regulator with fixed 3.3-V output, 8–40-V input range, 260-kHz fixed-frequency PWM control, and resistor-programmable current limit (5.5–7.6 A typical). It integrates a 120-mΩ DMOS high-side switch and supports soft-start via external capacitor for inrush current control in industrial power supplies.
For engineers reviewing the LM2679SDX-3.3/NOPB datasheet, LM2679SDX-3.3/NOPB pinout, LM2679SDX-3.3/NOPB application, or LM2679SDX-3.3/NOPB equivalent, key selection criteria include ±2% output tolerance over line/load/temperature, thermal shutdown protection, bootstrapped gate drive architecture, and compatibility with standard off-the-shelf 10-μH inductors and low-ESR output capacitors.
Technical Context
The LM2679SDX-3.3/NOPB implements a voltage-mode PWM controller with a fixed 260-kHz oscillator and internal error amplifier referenced to a 1.21-V feedback threshold. Its DMOS power switch operates with 0.12–0.225-Ω RDS(ON) across –40°C to 125°C, enabling >92% peak efficiency at 12-V input and 5-A load.
Current limiting is set by an external resistor (RADJ = 5.6 kΩ yields 6.3-A typical limit), while soft-start timing is controlled by a capacitor on the SS pin that linearly ramps duty cycle. The FB pin connects directly to the output for fixed versions, eliminating external divider components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | Fixed 3.3 V ±2% over full line, load, and temperature (–40°C to 125°C) |
| Input voltage range | 8 V to 40 V - supports wide industrial and battery-derived inputs without pre-regulation |
| Max output current | 5 A continuous - enables single-regulator solutions for mid-power embedded systems |
| Switch RDS(ON) | 0.12 Ω (typ) at 25°C - minimizes conduction loss and thermal rise under full load |
| Oscillator frequency | 260 kHz ±11% - enables use of compact, low-cost off-the-shelf inductors (e.g., 10 μH) |
| Current limit range | 3 A to 7 A via RADJ - allows precise fault-current tailoring without external sense resistors |
| Quiescent current | 4.2–6 mA - maintains low no-load power draw in always-on applications |
Pinout & Package
LM2679SDX-3.3/NOPB uses the 7-pin TO-263 (KTW) package with exposed thermal pad (10.10 mm × 8.89 mm), optimized for high-current PCB thermal management. Pin 1 is the switching node; pins 4 and 9 are tied to system ground; DAP must be soldered to PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain of internal DMOS FET - connects to inductor and Schottky diode cathode; switches between VIN and ~−0.5 V |
| 2 (VIN) | Input supply | High-side switch source and IC bias rail - requires low-impedance 3×15-μF/50-V ceramic input bypass |
| 3 (CB) | Bootstrap capacitor | Gate-drive boost node - requires 0.01-μF ceramic capacitor to SW to enable full FET enhancement |
| 4,9 (GND) | Power ground | Return path for input/output capacitors and thermal pad - must connect to low-inductance ground plane |
| 5 (IADJ) | Current limit adjust | Sets peak switch current via RADJ to GND - 5.6-kΩ yields 6.3-A typical limit per ICL = 37,125/RADJ |
| 6 (FB) | Feedback input | Direct connection to 3.3-V output - internal resistor divider sets regulation point; no external components needed |
| 7 (SS) | Soft-start | Controls output ramp rate - 1-nF to GND yields ~10-ms startup; floating disables soft-start |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120-mΩ DMOS switch | Eliminates external MOSFET and driver, reducing BOM count and layout complexity for 5-A buck designs |
| Resistor-programmable current limit | Enables precise overcurrent protection tuning (3–7 A) without adding sense resistors or comparators |
| 260-kHz fixed-frequency operation | Ensures predictable EMI profile and simplifies filter design using standardized inductor families |
| ±2% output voltage tolerance | Meets tight regulation requirements for FPGA core rails and industrial microcontrollers without post-regulation |
| Thermal shutdown + current limit | Provides dual-fault protection during short-circuit, overload, or inadequate heatsinking conditions |
Applications
| Industrial PLC Power Supply | Automotive Infotainment Pre-regulator |
|---|---|
|
Use Scenario: Provides stable 3.3-V rail for ARM-based controllers and CAN transceivers in programmable logic controllers operating from 24-V DC bus. IC Role / Device Role / Timing Role: Primary step-down regulator delivering 5-A continuous current with ±2% output accuracy and 260-kHz switching synchronized to system clock domain. Use Value: Eliminates need for external current-sense circuitry and reduces thermal footprint vs. discrete buck solutions - validated for 125°C junction operation. |
Use Scenario: Generates clean 3.3-V supply for display processors and audio codecs in automotive head units powered from 12-V battery with load-dump transients. IC Role / Device Role / Timing Role: Preregulator upstream of LDOs, handling wide 8–40-V input range including cold-crank (6.5 V) and load-dump (40 V) events. Use Value: Built-in thermal shutdown and adjustable current limit protect downstream circuits during battery fault conditions without external supervision. |
| Telecom Remote Radio Unit | Medical Imaging Sensor Interface |
|
Use Scenario: Powers FPGA and ADC subsystems in outdoor small-cell base stations requiring high efficiency and long-term reliability under temperature cycling. IC Role / Device Role / Timing Role: High-efficiency (>92% at 12-V input) buck converter with soft-start to prevent inrush-induced voltage sag on shared 48-V backplane. Use Value: 260-kHz fixed frequency enables deterministic EMI filtering; TO-263 package supports forced-air cooling in sealed enclosures. |
Use Scenario: Supplies noise-sensitive analog front-end circuits in portable ultrasound probes where EMI and thermal constraints limit component count. IC Role / Device Role / Timing Role: Single-chip 3.3-V regulator with direct FB connection and low 85-nA feedback bias current minimizing measurement offset errors. Use Value: Integrated switch and bootstrap driver reduce layout sensitivity to parasitic coupling - critical for sub-mV signal integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678SDX-3.3/NOPB | Lower 3-A output rating; identical pinout, package, and feature set except reduced current limit and RDS(ON) | Suitable only for ≤3-A loads; cannot replace LM2679SDX-3.3/NOPB in 5-A designs without derating or parallel stages | Select when full 5-A capability is unnecessary and cost reduction is prioritized over margin. |
| TPS54560DGQR | Adjustable output (0.8–36 V); 60-V max input; 5-A rating; requires external feedback divider and has different pinout | Supports variable output and higher input voltage but lacks fixed 3.3-V option and requires redesign of feedback network | Choose when system requires flexibility beyond 3.3 V or must tolerate >40-V transients - not drop-in compatible. |
Compared with LM2678SDX-3.3/NOPB and TPS54560DGQR, the LM2679SDX-3.3/NOPB uniquely delivers fixed 3.3-V/5-A regulation in a pin-compatible TO-263 package with integrated current-limit programming - offering lowest design effort for high-current, fixed-output industrial power rails.
Availability
LM2679SDX-3.3/NOPB is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, telecom remote radio units, and medical imaging sensor interfaces requiring stable component supply and long-lifecycle support.
Supply support for LM2679SDX-3.3/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 specializing in analog, embedded processing, and power management technologies, with decades of leadership in high-reliability power conversion ICs.
The LM2679 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for rapid, robust implementation of efficient step-down regulators using minimal external components and industry-standard magnetics.
FAQ
What is the maximum input voltage rating for LM2679SDX-3.3/NOPB?
The absolute maximum input voltage for LM2679SDX-3.3/NOPB is 45 V, with recommended operation limited to 8 V–40 V. Exceeding 40 V may trigger internal overvoltage protection or reduce reliability; the device is qualified for sustained operation up to 40 V across its full temperature range.
Does LM2679SDX-3.3/NOPB require an external feedback resistor divider?
No. LM2679SDX-3.3/NOPB is a fixed-output variant: its internal feedback divider is factory-trimmed for 3.3 V, so the FB pin connects directly to the output capacitor. External resistors are only required for the adjustable version (LM2679MX-ADJ/NOPB).
How is current limit set on LM2679SDX-3.3/NOPB?
Current limit is set by connecting a resistor (RADJ) between the IADJ pin and GND. For LM2679SDX-3.3/NOPB with default 5.6-kΩ RADJ, the typical peak switch current is 6.3 A, calculated as ICL = 37,125 / RADJ. This allows precise fault-current tailoring without external sensing.
What package type does LM2679SDX-3.3/NOPB use?
LM2679SDX-3.3/NOPB uses the 7-pin TO-263 (KTW) package with exposed thermal pad (10.10 mm × 8.89 mm). This surface-mount package provides superior thermal performance over TO-220 and is optimized for automated assembly and high-current PCB layouts.
Can LM2679SDX-3.3/NOPB operate without a soft-start capacitor?
Yes. The SS pin can be left floating to disable soft-start, allowing immediate turn-on. However, omitting the soft-start capacitor increases input surge current during startup - TI recommends a 1-nF capacitor to ground for controlled 10-ms output ramp in most 5-A applications.
LM2679SDX-3.3/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):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 3.3V
- 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 (6x5)
LM2679SDX-3.3/NOPB FAQ
1.How can I place an order for LM2679SDX-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679SDX-3.3/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 LM2679SDX-3.3/NOPB reliable?
The price and inventory of LM2679SDX-3.3/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2679SDX-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM2679SDX-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679SDX-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679SDX-3.3/NOPB?
LM2679SDX-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679SDX-3.3/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 LM2679SDX-3.3/NOPB?
For technical support, including LM2679SDX-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679SDX-3.3/NOPB requirements.
6.How does Aetrix verify that LM2679SDX-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2679SDX-3.3/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 LM2679SDX-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM2679SDX-3.3/NOPB?
All LM2679SDX-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679SDX-3.3/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 LM2679SDX-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM2679SDX-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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