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Texas Instruments LM2679SD-3.3/NOPB
- Part No.:
- LM2679SD-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2679SD-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:487
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Product details
Overview
LM2679SD-3.3/NOPB from Texas Instruments is a monolithic 5-A step-down (buck) DC/DC voltage regulator with fixed 3.3-V output, 8 V to 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 surge-current limiting in industrial power supplies.
For engineers reviewing the LM2679SD-3.3/NOPB datasheet, LM2679SD-3.3/NOPB pinout, LM2679SD-3.3/NOPB application, or LM2679SD-3.3/NOPB equivalent, key selection criteria include its ±2% output tolerance over line/load/temperature, thermal shutdown protection, bootstrapped gate drive architecture, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.
Technical Context
The LM2679SD-3.3/NOPB implements a fixed-frequency (260 kHz) current-mode PWM controller with internal DMOS high-side switch and bootstrap-driven gate driver. Its feedback loop senses output voltage directly at the FB pin (shorted to VOUT for fixed versions), enabling stable regulation without external divider resistors.
Current limiting is set by an external resistor (RADJ = 5.6 kΩ yields 6.3-A typical peak switch current), and soft-start is controlled by a capacitor on the SS pin that linearly ramps duty cycle. The device operates across –40°C to +125°C junction temperature and includes thermal shutdown and under-voltage lockout.
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 DC inputs |
| Max output current | 5 A continuous - enables single-regulator solutions for mid-power systems |
| Switch RDS(ON) | 0.12 Ω (typ) at 25°C - minimizes conduction loss and improves efficiency up to 92% |
| Oscillator frequency | 260 kHz ±11% - enables use of compact magnetics and reduces EMI filtering burden |
| Current limit range | 3 A to 7 A programmable via RADJ - allows tailoring fault protection to specific load requirements |
| Quiescent current | 6 mA max - maintains low no-load power draw in always-on systems |
Pinout & Package
LM2679SD-3.3/NOPB uses the 7-pin TO-263 (KTW) package with exposed thermal pad (DAP), measuring 10.10 mm × 8.89 mm. The DAP must be soldered to PCB ground plane for thermal performance and electrical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain node of internal DMOS FET; connects to inductor and Schottky diode cathode - switching node with high dv/dt |
| 2 (VIN) | Input supply | High-current input path to internal switch and bias circuitry; requires low-inductance bypassing near pin |
| 3 (CB) | Bootstrap capacitor | Connects 0.01-μF ceramic capacitor to SW pin to generate gate drive voltage > VIN for full FET enhancement |
| 4 (GND) | Power ground | Main return path for input/output currents and IC substrate; must tie to thermal pad and low-impedance ground plane |
| 5 (IADJ) | Current limit adjust | Accepts resistor to GND to set peak switch current per ICL = 37,125 / RADJ (Ω) |
| 6 (FB) | Feedback sense | Internally tied to 3.3-V reference; shorted to output for fixed version - no external divider needed |
| 7 (SS) | Soft-start control | Accepts capacitor to GND to ramp output voltage linearly; prevents inrush current during startup |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120-mΩ DMOS switch | Enables 5-A output without external MOSFET, reducing BOM count and layout complexity |
| Resistor-programmable current limit | Allows precise fault-current setting (3–7 A) without redesigning current-sense circuitry |
| Fixed 3.3-V output with ±2% tolerance | Eliminates external feedback resistors and ensures compliance with 3.3-V logic rail specifications |
| 260-kHz fixed-frequency operation | Permits predictable EMI filtering and consistent inductor sizing across designs |
| Thermal shutdown + UVLO | Provides autonomous protection against overheating and invalid input conditions without external supervision |
Applications
| Industrial PLC Power Supply | Automotive Infotainment Core Rail |
|---|---|
Use Scenario: Provides primary 3.3-V rail for microcontroller, FPGA, and interface ICs in programmable logic controllers operating from 24-V DC bus. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 3.3 V at up to 5 A with tight line/load regulation and thermal robustness. Use Value: Eliminates need for secondary LDOs by meeting ±2% tolerance and low ripple (<33 mV pk-pk) requirements for digital logic rails. | Use Scenario: Generates 3.3-V core supply for SoC and display controller in automotive head units powered from 12-V battery with load-dump transients. IC Role / Device Role / Timing Role: High-reliability buck converter with 8–40 V input range and built-in thermal shutdown for harsh automotive environments. Use Value: Withstands cold-crank (6.5 V) and load-dump (40 V) events while maintaining regulation - no external TVS required for basic protection. |
| Telecom Remote Radio Unit | Medical Diagnostic Imaging Module |
Use Scenario: Powers FPGA-based signal processing and ADC/DAC interfaces in outdoor 4G/5G remote radio heads with -40°C to +85°C ambient requirement. IC Role / Device Role / Timing Role: Efficient (>90%) 3.3-V step-down regulator with soft-start to prevent backplane voltage sag during hot-swap insertion. Use Value: Soft-start capacitor (e.g., 100 nF) limits inrush to <2 A, avoiding tripping upstream 24-V DC-DC converters. | Use Scenario: Supplies 3.3-V logic rail for image sensor interface and real-time control MCU in portable ultrasound devices with battery+adapter input. IC Role / Device Role / Timing Role: Single-chip buck solution with low quiescent current (6 mA) and thermal shutdown for safety-critical medical applications. Use Value: Meets IEC 60601 creepage/clearance requirements via TO-263 package isolation and eliminates need for discrete current-limiting circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678SD-3.3/NOPB | Same pinout, 3.3-V fixed output, but 2.5-A max output and 280-kHz oscillator | Suitable only for lower-current applications (<2.5 A); lacks adjustable current limit | Select when 5-A capability is unnecessary and board space or cost optimization is prioritized |
| TPS54560QDGQRQ1 | Automotive-grade 60-V input, 5-A synchronous buck with integrated high/low-side FETs and 3.5-V to 60-V range | Supports higher input voltages and includes sync capability; requires different compensation network | Choose for AEC-Q100-compliant designs requiring extended input range or synchronization to system clock |
Compared with LM2679SD-3.3/NOPB, LM2678SD-3.3/NOPB offers reduced current capacity and no current-limit programming, while TPS54560QDGQRQ1 adds automotive qualification and synchronous rectification but increases design complexity and cost.
Availability
LM2679SD-3.3/NOPB is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, telecom remote radio units, and medical imaging modules requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2679SD-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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies with broad industrial, automotive, and communications reach.
The LM2679 series belongs to TI's SIMPLE SWITCHER® family of integrated DC/DC regulators, designed specifically to simplify high-efficiency buck converter implementation using minimal external components and standardized magnetics.
FAQ
What is the maximum recommended input voltage for LM2679SD-3.3/NOPB?
The absolute maximum input voltage for LM2679SD-3.3/NOPB is 45 V, but the recommended operating range is 8 V to 40 V. Operation above 40 V risks exceeding safe operating area limits and may trigger internal protection circuits. For sustained reliability, keep VIN ≤40 V under all conditions including transients.
Does LM2679SD-3.3/NOPB require an external feedback resistor divider?
No. LM2679SD-3.3/NOPB is a fixed-output variant: its internal feedback divider is factory-trimmed to 3.3 V, so the FB pin is internally connected to the output reference and must be shorted directly to the output capacitor. Adding external resistors will disrupt regulation and cause incorrect output voltage.
How is current limit set on LM2679SD-3.3/NOPB?
Current limit is set by connecting a resistor (RADJ) between the IADJ pin (Pin 5) and GND. The peak switch current follows ICL = 37,125 / RADJ (Ω). For the standard 5.6-kΩ resistor, LM2679SD-3.3/NOPB delivers 6.3-A typical current limit, adjustable from 3 A to 7 A depending on RADJ value.
What package type does LM2679SD-3.3/NOPB use, and is thermal pad connection required?
LM2679SD-3.3/NOPB uses the 7-pin TO-263 (KTW) package with exposed thermal pad (DAP). Yes - the DAP must be soldered to a minimum 100-mm² copper area tied to GND for thermal performance and electrical stability. Omitting this connection causes junction temperature rise >20°C and potential thermal shutdown.
Can LM2679SD-3.3/NOPB operate with input voltage below 8 V?
No. LM2679SD-3.3/NOPB has an under-voltage lockout (UVLO) threshold of approximately 7.5 V. Input voltage below 8 V prevents startup and disables the internal switch. This is a hard specification - operation below 8 V is not supported, and attempting it results in no output regulation or undefined behavior.
LM2679SD-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 (5x6)
LM2679SD-3.3/NOPB FAQ
1.How can I place an order for LM2679SD-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679SD-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 LM2679SD-3.3/NOPB reliable?
The price and inventory of LM2679SD-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 LM2679SD-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM2679SD-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679SD-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679SD-3.3/NOPB?
LM2679SD-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679SD-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 LM2679SD-3.3/NOPB?
For technical support, including LM2679SD-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679SD-3.3/NOPB requirements.
6.How does Aetrix verify that LM2679SD-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2679SD-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 LM2679SD-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM2679SD-3.3/NOPB?
All LM2679SD-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679SD-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 LM2679SD-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM2679SD-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2679SD-3.3/NOPB Tags
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