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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Texas Instruments LM2679S-3.3/NOPB

Name: LM2679S-3.3/NOPB
Brand: Texas Instruments
SKU: LM2679S-3.3/NOPB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LM2679S-3.3/NOPB

Manufacturer:: Texas Instruments

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: TO-263-8, D2PAK (7 Leads + Tab), TO-263CA

Datasheet:: LM2679S-3.3/NOPB.pdf

Description:: IC REG BUCK 3.3V 5A TO263

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Product details

Overview

LM2679S-3.3/NOPB from Texas Instruments is a monolithic 5-A step-down (buck) DC/DC voltage regulator with fixed 3.3 V output, integrated 120-mΩ DMOS power switch, 260-kHz fixed-frequency oscillator, and resistor-programmable current limit (5.5–7.6 A). It operates from 8 V to 40 V input and delivers ±2% output voltage tolerance over line, load, and temperature (–40°C to 125°C), targeting industrial power supplies and battery-charger pre-regulators.

For engineers reviewing the LM2679S-3.3/NOPB datasheet, LM2679S-3.3/NOPB pinout, LM2679S-3.3/NOPB application, or LM2679S-3.3/NOPB equivalent, key selection criteria include its 5-A continuous output capability, soft-start control via external capacitor, bootstrapped high-side gate drive, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.

Technical Context

The LM2679S-3.3/NOPB implements a synchronous-buck topology using an internal N-channel DMOS high-side switch controlled by a fixed 260-kHz PWM oscillator. Feedback is taken directly from the output (no external divider required) to maintain 3.3 V regulation with ±2% accuracy across 100 mA–5 A load and 8–40 V input.

Current limiting is set by an external resistor on the Current Adjust pin, yielding a programmable peak switch current of 5.5–7.6 A at 25°C. Soft-start is implemented via a capacitor on the SS pin, controlling output ramp rate to suppress inrush current; the CB pin enables bootstrapped gate drive for full enhancement of the internal MOSFET.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3 V ±2% over full line/load/temperature range - ensures stable logic supply without external feedback resistors.
Max Output Current	5 A continuous - supports high-power microcontrollers, FPGAs, and industrial sensors without external current boosting.
Input Voltage Range	8 V to 40 V - accommodates 12 V/24 V industrial rails and automotive battery variations with headroom for transients.
Switch R_DS(ON)	0.12 Ω typical at 25°C - minimizes conduction loss and enables >92% peak efficiency at 12 V_IN/5 A.
Oscillator Frequency	260 kHz ±11% - enables use of compact, low-cost off-the-shelf inductors (e.g., 10–22 µH) and reduces EMI compared to MHz-range converters.
Current Limit Range	5.5 A to 7.6 A (set by 5.6 kΩ–3.3 kΩ resistor to GND) - allows precise fault-current tailoring for system-level short-circuit protection.
Soft-Start Control	Capacitor-programmable (e.g., 1 nF → ~10 ms ramp) - eliminates input surge current during cold start and prevents output overshoot.

Pinout & Package

LM2679S-3.3/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad (10.10 mm × 8.89 mm), optimized for high-power dissipation in compact PCB layouts.

Pin/Terminal	Circuit Role	Design Meaning
1 (Switch Output)	High-side MOSFET drain node	Switching node connecting to inductor and Schottky diode cathode; requires low-inductance layout to minimize ringing and EMI.
2 (Input)	Main power input	Connects to 8–40 V source and high-frequency input bypass capacitors; shortest possible trace to ground reduces noise coupling.
3 (CB)	Bootstrap capacitor connection	Accepts 0.01 µF ceramic capacitor to VSW to generate gate drive voltage >V_IN, ensuring full MOSFET enhancement and low R_DS(ON).
4 (GND)	Power ground reference	Common return for input/output capacitors, thermal pad, and internal circuitry; must be tied to solid ground plane for thermal and EMI performance.
5 (Current Adjust)	Peak current limit programming	Receives 1.21 V reference; connects to GND via resistor (e.g., 5.6 kΩ) to set 6.3 A typical current limit per I_CL = 37,125/R_ADJ.
6 (FB)	Feedback sense input	Internally connected to 3.3 V output - no external divider needed; direct tie to output capacitor ensures accurate regulation.
7 (SS)	Soft-start timing input	Accepts capacitor to GND (e.g., 1 nF) to linearly ramp duty cycle; floating disables soft-start.

Key Features

Feature	Design Value
Integrated 120-mΩ DMOS switch	Enables 5-A output without external MOSFETs; reduces BOM count and layout complexity while maintaining >92% peak efficiency.
Resistor-programmable current limit	Allows precise fault-current setting (5.5–7.6 A) to match system-level fuse or cable ratings without redesigning power stage.
Fixed 260-kHz switching frequency	Guarantees predictable EMI profile and simplifies filter design; supports use of standardized, cost-optimized inductors from Renco, Pulse, Coilcraft.
Direct-output feedback (fixed 3.3 V)	Eliminates external resistor divider, reducing component count, layout area, and potential drift sources in precision 3.3 V rail generation.
Thermal shutdown + soft-start	Provides autonomous fault recovery under overload/overtemperature and prevents input surge during power-up in battery-powered systems.

Applications

Industrial PLC Power Supply	Automotive Infotainment Pre-regulator
Use Scenario: Provides clean, regulated 3.3 V for microcontroller, CAN transceiver, and display interface in programmable logic controllers operating from 24 V DC bus. IC Role / Device Role / Timing Role: Primary buck regulator delivering 5 A continuous output; replaces discrete switcher designs requiring external MOSFETs and complex compensation. Use Value: ±2% output tolerance ensures reliable operation of 3.3 V I/O peripherals; 8–40 V input range tolerates 24 V bus transients up to 40 V without dropout.	Use Scenario: Generates stable 3.3 V rail for SoC and memory subsystems in head-unit systems powered from vehicle battery (9–16 V nominal, up to 40 V load dump). IC Role / Device Role / Timing Role: High-efficiency preregulator stepping down battery voltage before LDOs; handles wide input variation with fixed 260-kHz clock for predictable EMI filtering. Use Value: 5-A capability supports burst-mode CPU loads; soft-start prevents ignition-switch-induced voltage sag; thermal shutdown protects against under-dash ambient temperatures.
Portable Test Equipment Power	LED Driver Bias Supply
Use Scenario: Powers FPGA-based signal processing core and ADC/DAC interfaces in handheld multimeters and oscilloscopes running from Li-ion packs (10–16.8 V). IC Role / Device Role / Timing Role: Main DC/DC converter delivering low-noise 3.3 V; uses ceramic input/output caps and tight layout to minimize ripple (<20 mV_PP). Use Value: 0.12 Ω R_DS(ON) minimizes heat rise in sealed enclosures; resistor-adjustable current limit avoids nuisance tripping during FPGA configuration surges.	Use Scenario: Supplies bias voltage to constant-current LED driver ICs in architectural lighting controllers requiring robust 3.3 V logic supply alongside high-current LED strings. IC Role / Device Role / Timing Role: Dedicated 3.3 V regulator isolated from noisy LED switching paths; GND pin separation and CB bootstrap reduce cross-talk. Use Value: Fixed 3.3 V output eliminates feedback resistor drift concerns; TO-263 thermal pad enables mounting on heatsink for sustained 5 A operation near hot LED drivers.

Industrial PLC Power Supply

Automotive Infotainment Pre-regulator

Use Scenario: Provides clean, regulated 3.3 V for microcontroller, CAN transceiver, and display interface in programmable logic controllers operating from 24 V DC bus.

IC Role / Device Role / Timing Role: Primary buck regulator delivering 5 A continuous output; replaces discrete switcher designs requiring external MOSFETs and complex compensation.

Use Value: ±2% output tolerance ensures reliable operation of 3.3 V I/O peripherals; 8–40 V input range tolerates 24 V bus transients up to 40 V without dropout.

Use Scenario: Generates stable 3.3 V rail for SoC and memory subsystems in head-unit systems powered from vehicle battery (9–16 V nominal, up to 40 V load dump).

IC Role / Device Role / Timing Role: High-efficiency preregulator stepping down battery voltage before LDOs; handles wide input variation with fixed 260-kHz clock for predictable EMI filtering.

Use Value: 5-A capability supports burst-mode CPU loads; soft-start prevents ignition-switch-induced voltage sag; thermal shutdown protects against under-dash ambient temperatures.

Portable Test Equipment Power

LED Driver Bias Supply

Use Scenario: Powers FPGA-based signal processing core and ADC/DAC interfaces in handheld multimeters and oscilloscopes running from Li-ion packs (10–16.8 V).

IC Role / Device Role / Timing Role: Main DC/DC converter delivering low-noise 3.3 V; uses ceramic input/output caps and tight layout to minimize ripple (<20 mV_PP).

Use Value: 0.12 Ω R_DS(ON) minimizes heat rise in sealed enclosures; resistor-adjustable current limit avoids nuisance tripping during FPGA configuration surges.

Use Scenario: Supplies bias voltage to constant-current LED driver ICs in architectural lighting controllers requiring robust 3.3 V logic supply alongside high-current LED strings.

IC Role / Device Role / Timing Role: Dedicated 3.3 V regulator isolated from noisy LED switching paths; GND pin separation and CB bootstrap reduce cross-talk.

Use Value: Fixed 3.3 V output eliminates feedback resistor drift concerns; TO-263 thermal pad enables mounting on heatsink for sustained 5 A operation near hot LED drivers.

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2678-3.3/NOPB	Same pinout, 65-kHz oscillator, lower efficiency (~88% at 5 A), higher R_DS(ON) (0.22 Ω)	Better suited for low-EMI, low-RMS-current applications where size is less critical than noise	Select when EMI filtering simplicity outweighs efficiency and thermal constraints.
TPS54560BQPWPRQ1	42 V input, 5.5 A, adjustable output, 100–2500 kHz sync-capable, smaller 8-pin SO PowerPAD	Requires external feedback divider; supports spread-spectrum and enable sequencing	Choose for AEC-Q100 automotive qualification, programmable frequency, or tighter thermal footprint.

Compared with LM2678-3.3/NOPB, LM2679S-3.3/NOPB delivers higher efficiency and lower thermal rise at 5 A due to its 260-kHz architecture and 0.12 Ω switch; versus TPS54560BQPWPRQ1, it offers simpler fixed-output implementation but lacks automotive qualification and frequency flexibility.

Availability

LM2679S-3.3/NOPB is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, and portable test equipment requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LM2679S-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 leader specializing in analog and embedded processing technologies, with decades of expertise in power management IC design and manufacturing.

The LM2679 series belongs to TI's SIMPLE SWITCHER® family - engineered for ease of use in high-current DC/DC conversion, minimizing external component count while delivering robust performance in industrial, automotive, and computing power applications.

FAQ

What is the maximum input voltage rating for LM2679S-3.3/NOPB?

The absolute maximum input voltage for LM2679S-3.3/NOPB is 45 V, but the recommended operating range is 8 V to 40 V DC. Operation above 40 V risks exceeding safe operating area limits and may trigger internal protection circuits. For sustained reliability in 24 V industrial systems with load-dump transients, ensure input clamping or filtering keeps VIN ≤40 V.

Does LM2679S-3.3/NOPB require external feedback resistors?

No, LM2679S-3.3/NOPB does not require external feedback resistors. Its FB pin is internally connected to the 3.3 V output reference, so it must be tied directly to the output capacitor's positive terminal. This eliminates resistor tolerance errors and simplifies layout - a key advantage over adjustable regulators like the LM2679-ADJ.

How is current limit set on LM2679S-3.3/NOPB?

Current limit on LM2679S-3.3/NOPB is set by connecting a resistor (RADJ) between the Current Adjust pin (Pin 5) and GND. The peak switch current follows I_CL = 37,125 / RADJ (in ohms), yielding 6.3 A typical with a 5.6 kΩ resistor. This allows precise matching to system-level fusing and cable ampacity without modifying the power stage.

What package type is used for LM2679S-3.3/NOPB?

LM2679S-3.3/NOPB is supplied in the 7-pin TO-263 (KTW) package - a surface-mount variant with an exposed thermal pad measuring 10.10 mm × 8.89 mm. This package provides superior thermal performance versus TO-220 and supports high-current operation with proper PCB copper area and thermal vias beneath the DAP.

Can LM2679S-3.3/NOPB be used with ceramic output capacitors?

Yes, LM2679S-3.3/NOPB is compatible with low-ESR ceramic output capacitors. The datasheet recommends ≥400 µF total capacitance (e.g., parallel 220 µF + 100 µF + 100 µF X7R ceramics) to maintain loop stability and limit output ripple to <1% of 3.3 V. Ensure capacitor voltage rating exceeds 6.3 V and RMS current rating exceeds inductor ripple current.

LM2679S-3.3/NOPB Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: SIMPLE SWITCHER®

Package/Case:: TO-263-8, D2PAK (7 Leads + Tab), TO-263CA

Packaging:: Tube

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:: TO-263 (DDPAK-7)

LM2679S-3.3/NOPB FAQ

1.How can I place an order for LM2679S-3.3/NOPB through Aetrix?

Please submit a Request for Quotation (RFQ) for LM2679S-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 LM2679S-3.3/NOPB reliable?

The price and inventory of LM2679S-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 LM2679S-3.3/NOPB is usually 5 days.

3.What payment methods are accepted for LM2679S-3.3/NOPB?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679S-3.3/NOPB transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LM2679S-3.3/NOPB?

LM2679S-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM2679S-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 LM2679S-3.3/NOPB?

For technical support, including LM2679S-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679S-3.3/NOPB requirements.

6.How does Aetrix verify that LM2679S-3.3/NOPB is sourced from the original manufacturer or authorized distributors?

All LM2679S-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 LM2679S-3.3/NOPB meets industry standards.

7.What is the process for return or replacement of LM2679S-3.3/NOPB?

All LM2679S-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679S-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 LM2679S-3.3/NOPB part is unused and in its original packaging.

Return procedure for LM2679S-3.3/NOPB:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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