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Texas Instruments LM2676SX-ADJ
- Part No.:
- LM2676SX-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2676SX-ADJ.pdf
- Description:
- IC REG BUCK ADJ 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,785
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Product details
Overview
LM2676SX-ADJ from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator delivering up to 3A output current with adjustable output voltage (1.2V to 37V), 260kHz fixed-frequency operation, ±2% output voltage tolerance over line/load/temperature, and 8V–40V input range. It integrates a 150mΩ DMOS high-side switch and supports ON/OFF control for low-power standby mode in industrial power supplies.
For engineers reviewing the LM2676SX-ADJ datasheet, LM2676SX-ADJ pinout, LM2676SX-ADJ application, or LM2676SX-ADJ equivalent, key selection criteria include its adjustable feedback architecture, thermal shutdown and current limiting protection, 50µA shutdown quiescent current, and compatibility with standard off-the-shelf inductors and Schottky diodes in TO-263-7 packaging.
Technical Context
The LM2676SX-ADJ implements a voltage-mode PWM controller with a fixed 260kHz oscillator and internal high-side DMOS FET. Its feedback loop senses output voltage via an external resistor divider connected to the FB pin, enabling precise regulation across the 1.2V–37V range.
It operates in continuous conduction mode (CCM) at full load and transitions to discontinuous mode (DCM) under light loads. Protection features include thermal shutdown, cycle-by-cycle current limiting (typ. 4.5A), and built-in soft-start functionality through the CB pin bootstrap circuit.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Up to 3A continuous - supports medium-power industrial loads without external current boosting. |
| Input Voltage Range | 8V to 40V - compatible with 12V/24V/36V industrial bus rails and battery-backed systems. |
| Output Voltage Range | 1.2V to 37V adjustable - set via external resistor divider on FB pin; enables single BOM for multiple output voltages. |
| Switching Frequency | 260kHz ±11% - enables use of compact, off-the-shelf inductors (e.g., 33µH) and reduces EMI compared to higher-frequency alternatives. |
| Feedback Reference | 1.21V ±1.2% - defines output as VOUT = 1.21V × (1 + R1/R2); enables tight regulation with standard 1% resistors. |
| Quiescent Current | 50µA in shutdown - minimizes system standby power loss; enabled by pulling ON/OFF pin low. |
| Efficiency | Up to 94% - achieved via 150mΩ RDS(ON) DMOS switch and optimized gate drive; measured at VIN=24V, VOUT=12V, IOUT=3A. |
| Operating Temperature | –40°C to +125°C junction - suitable for extended-temperature industrial and metering environments. |
Pinout & Package
LM2676SX-ADJ is supplied in the KTW (TO-263-7) thermally enhanced surface-mount package, featuring a 10.1mm × 15.24mm outline and exposed thermal pad soldered to PCB ground plane for optimal heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch Output | Drain node of internal high-side DMOS FET; connects directly to inductor and cathode of external catch diode; switches between VIN and ~–0.5V during operation. |
| 2 (VIN) | Input Supply | Main power input (8–40V); must be bypassed with low-ESR capacitor placed adjacent to pin to minimize switching noise and supply impedance. |
| 3 (CB) | Bootstrap Capacitor | Connects to SW via 100nF ceramic capacitor; provides gate drive voltage >VIN to fully enhance internal FET and minimize conduction losses. |
| 4 (GND) | Power Ground | Primary return path for input/output capacitors and internal circuitry; requires low-inductance connection to thermal pad and system ground plane. |
| 5 (NC) | No Connect | Internally unconnected; must remain floating - no routing or soldering permitted. |
| 6 (FB) | Feedback Input | Senses output voltage via external resistor divider; regulates VOUT = 1.21V × (1 + R1/R2); high-impedance (85nA bias) for minimal divider loading. |
| 7 (ON/OFF) | Enable Control | Logic-level enable: ≥1.4V = active regulation; ≤0.8V = shutdown (50µA IQ); internal 20µA pull-up allows open-circuit default ON operation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 150mΩ DMOS Switch | Enables high-efficiency buck conversion without external MOSFETs; eliminates gate driver complexity and layout sensitivity. |
| Fixed 260kHz Oscillator | Provides predictable EMI profile and simplifies filter design; allows use of standardized, cost-effective inductors from Renco, Pulse, and Coilcraft. |
| ±2% Output Tolerance | Guaranteed over full line, load, and temperature (–40°C to +125°C); reduces need for post-production trimming in production test. |
| Thermal Shutdown & Current Limit | Protects against overload and ambient overheating; cycle-by-cycle current limit (4.5A typ.) prevents damage during short-circuit events. |
| WEBENCH® Design Integration | Supports instant schematic generation, BOM creation, and performance simulation directly from TI's online tool - accelerates prototyping and validation. |
Applications
| Communication Module Power | Electricity Meter Supply |
|---|---|
Use Scenario: Powers baseband processor, RF transceiver, and isolated RS-485 interface in cellular/NB-IoT smart meters. IC Role / Device Role / Timing Role: Primary non-isolated 3.3V/5V buck converter supplying digital logic and analog front-end circuitry. Use Value: Delivers stable 3A output with <1% ripple under dynamic load steps; 50µA shutdown current extends battery backup runtime. | Use Scenario: Generates regulated 5V rail for metrology ASIC, real-time clock, and LCD backlight in Class 0.5S electricity meters. IC Role / Device Role / Timing Role: Main DC-DC regulator converting 12–36V utility-supplied or battery-backed input to precision 5V output. Use Value: ±2% output tolerance ensures accurate ADC reference stability; wide input range accommodates fluctuating transformer-derived supplies. |
| Calling Button Panel Supply | Motor Drive Auxiliary Rail |
Use Scenario: Supplies 12V logic and LED indicators in building intercom panels powered from PoE or 24V wall adapters. IC Role / Device Role / Timing Role: Adjustable buck regulator configured for 12V output driving microcontroller, optocouplers, and status LEDs. Use Value: 260kHz switching avoids audible noise in occupied spaces; TO-263 thermal pad enables passive cooling without heatsink. | Use Scenario: Provides isolated 5V/3.3V auxiliary power for gate drivers and MCU in 24V BLDC motor controllers. IC Role / Device Role / Timing Role: Secondary buck stage deriving clean logic supply from main motor bus, independent of H-bridge switching noise. Use Value: Built-in current limiting protects against inductive kickback faults; thermal shutdown prevents latch-up during stall conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596SX-ADJ | Lower 3A current rating, 150kHz switching frequency, higher RDS(ON) (220mΩ), wider VOUT tolerance (±4%). | Less efficient at high load; larger inductors required; less suitable for space-constrained designs. | Choose when cost sensitivity outweighs efficiency and size requirements; verify thermal margin at full load. |
| TPS54302DDAR | Higher 3A rating, 2.5MHz switching, integrated compensation, smaller 8-pin SOIC package, but narrower 3–28V input range. | Better for compact, high-density layouts; unsuitable for 36–40V industrial inputs or legacy 40V-capable designs. | Prefer for new designs targeting miniaturization and faster transient response; avoid if input exceeds 28V or thermal pad mounting is mandatory. |
Compared with LM2676SX-ADJ, LM2596SX-ADJ trades efficiency and precision for lower cost, while TPS54302DDAR offers higher integration and frequency at the expense of input voltage range and thermal performance - making LM2676SX-ADJ optimal for ruggedized 8–40V industrial buck applications requiring proven reliability and thermal robustness.
Availability
LM2676SX-ADJ is available at Aetrix Electronics and suitable for communication modules, electricity meters, calling button operating panels, and motor drives requiring stable component supply, long-term lifecycle support, and extended-temperature operation.
Supply support for LM2676SX-ADJ 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 ICs and industrial-grade reliability.
The LM2676 series belongs to TI's SIMPLE SWITCHER® portfolio, designed specifically for ease-of-use, high-efficiency, and robustness in industrial, metering, and communications power applications - minimizing external component count and design iteration time.
FAQ
What is the maximum output voltage achievable with LM2676SX-ADJ?
The LM2676SX-ADJ supports an adjustable output voltage range from 1.2V to 37V, determined by the external resistor divider on the FB pin. The upper limit is constrained by the absolute maximum ratings of the internal circuitry and external components - particularly the voltage rating of the output capacitor and catch diode. At 37V output, ensure VIN remains ≤40V and all external components are rated accordingly.
Does LM2676SX-ADJ require an external catch diode, and what type is recommended?
Yes, LM2676SX-ADJ requires an external Schottky catch diode connected between the SW pin and GND. A 3A-rated, low-forward-voltage (≤0.5V) Schottky diode such as the SB560 or MBR360 is recommended to minimize conduction loss and maintain high efficiency. Fast recovery and low reverse leakage are critical for stable operation across temperature.
How does the ON/OFF pin function in LM2676SX-ADJ, and what is its threshold?
The ON/OFF pin on LM2676SX-ADJ enables logic-level control of regulator operation: voltage ≥1.4V enables regulation, while ≤0.8V forces shutdown with 50µA quiescent current. An internal 20µA pull-up allows default ON operation when left floating. The pin includes a 7V Zener clamp, so drive voltage must not exceed 6V absolute maximum to prevent damage.
Can LM2676SX-ADJ operate with input voltage below 8V?
No - LM2676SX-ADJ has a specified minimum input voltage of 8V per its Recommended Operating Conditions. Operation below 8V may result in failure to start, unstable regulation, or undefined behavior due to insufficient headroom for the internal bias circuitry and gate drive. For sub-8V inputs, consider alternative regulators such as the LM2576 or TPS54202.
What thermal considerations apply to LM2676SX-ADJ in the TO-263-7 (KTW) package?
In the KTW package, LM2676SX-ADJ achieves a junction-to-ambient thermal resistance (RθJA) of 35°C/W with 0.4896 in² copper area, dropping to 26°C/W with 1.0064 in². The exposed thermal pad must be soldered to a solid ground plane with ≥4 thermal vias. Without adequate copper, junction temperature can exceed 125°C at full 3A load - derating or forced airflow may be required above 2A in compact enclosures.
LM2676SX-ADJ 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:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 3A
- 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)
LM2676SX-ADJ FAQ
1.How can I place an order for LM2676SX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2676SX-ADJ 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 LM2676SX-ADJ reliable?
The price and inventory of LM2676SX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2676SX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2676SX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2676SX-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2676SX-ADJ?
LM2676SX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2676SX-ADJ 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 LM2676SX-ADJ?
For technical support, including LM2676SX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2676SX-ADJ requirements.
6.How does Aetrix verify that LM2676SX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2676SX-ADJ 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 LM2676SX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2676SX-ADJ?
All LM2676SX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2676SX-ADJ, 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 LM2676SX-ADJ part is unused and in its original packaging.
Return procedure for LM2676SX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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