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Texas Instruments LM2676SX-12
- Part No.:
- LM2676SX-12
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2676SX-12.pdf
- Description:
- IC REG BUCK 12V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,441
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Product details
Overview
LM2676SX-12 from Texas Instruments is a monolithic step-down (buck) DC/DC switching regulator delivering up to 3A output current with fixed 12V output, 260kHz fixed-frequency operation, ±2% output voltage tolerance over full line/load/temperature, and 94% peak efficiency at 24VIN/3A. It serves as the primary power conversion stage in industrial power supplies and motor drive subsystems.
For engineers reviewing the LM2676SX-12 datasheet, LM2676SX-12 pinout, LM2676SX-12 application, or LM2676SX-12 equivalent, key selection criteria include its 8–40V input range, integrated 150mΩ DMOS high-side switch, ON/OFF control interface, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and Schottky diodes.
Technical Context
The LM2676SX-12 implements a voltage-mode PWM controller with a fixed 260kHz oscillator and internal high-side DMOS FET. Its feedback loop uses a precision 1.21V reference and low-bias-current amplifier (85nA) to regulate output via direct connection of FB to VOUT - no external divider required for the fixed 12V version.
It operates across –40°C to +125°C junction temperature, supports shutdown via TTL-compatible ON/OFF pin (1.4V threshold), and integrates cycle-by-cycle current limiting (typ. 4.5A), thermal shutdown, and bootstrap capacitor (CB) drive for gate enhancement. The switch node (VSW) swings from VIN to ~–0.5V during turn-off.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | Fixed 12V ±2% over –40°C to 125°C, 100mA–3A load, 15–40V input - eliminates need for external feedback resistors. |
| Input voltage range | 8V to 40V DC - supports wide-range industrial inputs including 12V, 24V, and 36V nominal rails. |
| Switching frequency | 260kHz ±11% - enables use of compact, standardized inductors (e.g., 33µH) and reduces EMI compared to lower frequencies. |
| Efficiency | Up to 94% at 24VIN/3A - achieved via 150mΩ RDS(ON) DMOS switch and optimized gate drive. |
| Quiescent current | 6mA typical operating IQ; 50µA standby when ON/OFF = 0V - enables low-power hold modes in battery-backed systems. |
| Current limit | 4.5A typical cycle-by-cycle limit - protects against short-circuit and overload without external sensing. |
| Thermal shutdown | Activates at TJ ≥ 160°C - provides fail-safe protection under sustained overload or poor heatsinking. |
Pinout & Package
LM2676SX-12 is supplied in the KTW (TO-263-7) package: thermally enhanced 7-pin surface-mount variant with exposed DAP (die attach pad) soldered to PCB ground plane for optimal thermal performance (RθJA = 35°C/W with 0.4896 in² copper).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain of internal high-side DMOS FET; connects to inductor and cathode of external Schottky diode - high dv/dt node requiring tight layout. |
| 2 (VIN) | Input supply | Main power input (8–40V); must be bypassed with low-ESR capacitor placed adjacent to pin to minimize switching noise injection. |
| 3 (CB) | Bootstrap capacitor | Connects to SW via 100nF ceramic capacitor - lifts gate drive above VIN to fully enhance internal FET and minimize conduction loss. |
| 4 (GND) | Power ground | Primary return path for VIN, SW, and internal circuitry; must tie directly to system ground plane and share copper area with CIN/COUT. |
| 5 (NC) | No connect | Internally unconnected; electrically isolated - must remain floating, not tied to GND or any other net. |
| 6 (FB) | Feedback sense | Direct connection to VOUT sets regulation point - no resistor divider needed for fixed 12V version; sensitive to noise coupling. |
| 7 (ON/OFF) | Enable control | TTL-compatible digital input: >1.4V = active regulation; <0.8V = shutdown (50µA IQ); internal 20µA pull-up allows open-circuit enable. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 150mΩ DMOS power switch | Enables 3A continuous output without external MOSFET; reduces BOM count and layout complexity versus controller-only solutions. |
| Fixed 12V output with ±2% tolerance | Guarantees stable rail for microcontrollers, sensors, and analog circuitry without trimming or calibration - simplifies validation. |
| 260kHz fixed-frequency PWM | Provides predictable EMI profile and enables use of small, low-cost, off-the-shelf inductors (e.g., Pulse PA4342 series). |
| ON/OFF logic control with 50µA standby | Supports system-level power sequencing and low-power sleep states - critical for energy-sensitive industrial and metering applications. |
| Built-in thermal shutdown & current limiting | Eliminates need for external fault protection circuitry; ensures robust operation under transient overloads or ambient temperature excursions. |
Applications
| Communication Module Power | Electricity Meter Supply |
|---|---|
|
Use Scenario: Powers baseband processor, RF transceiver, and isolation interfaces in cellular/NB-IoT communication modules operating from 12–36V DC bus. IC Role / Device Role / Timing Role: Primary 12V buck converter supplying regulated rail to MCU and analog front-end; operates continuously with dynamic load steps. Use Value: Delivers 3A peak current with <1% output ripple using standard 33µH inductor and 220µF low-ESR capacitor - meets EN 61000-4-5 surge immunity requirements. |
Use Scenario: Generates stable 12V rail for metrology ASIC, real-time clock, and LCD backlight in Class 0.5S electricity meters. IC Role / Device Role / Timing Role: Isolated secondary-side regulator fed from flyback transformer; must maintain regulation during AC line dips and harmonics. Use Value: Maintains ±2% output accuracy across –25°C to +70°C ambient and 100mA–2.5A load range - ensures consistent ADC reference and RTC timing stability. |
| Calling Button Panel Supply | Motor Drive Auxiliary Power |
|
Use Scenario: Provides 12V power to microcontroller, LED indicators, and touch-sensing circuitry in building intercom and elevator call panels. IC Role / Device Role / Timing Role: Standby-capable primary regulator enabling instant wake-on-button-press; spends >95% time in 50µA shutdown mode. Use Value: Achieves <100mW total standby power (including LDOs and MCU) - extends battery life in backup-powered installations beyond 5 years. |
Use Scenario: Supplies gate driver ICs, op-amps, and position sensor circuitry in 24V DC brushless motor drives for HVAC and industrial automation. IC Role / Device Role / Timing Role: Auxiliary power source decoupled from main H-bridge; must reject high dv/dt noise from motor switching. Use Value: With proper CB capacitor placement and ground plane design, maintains <50mVpp output ripple even during 10A motor phase commutation transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2675MX-12 | Lower 1A output current rating; same 260kHz frequency and 12V fixed output; TO-263-5 package (no NC pin, no CB pin - integrated bootstrap) | Suitable only for sub-1A loads; lacks ON/OFF control and separate CB pin - less flexible for noise-sensitive or sequenced designs. | Select LM2675MX-12 only if load current ≤1A and board space is constrained - it uses smaller footprint but sacrifices headroom and control features. |
| LMR14030SDDAR | 40V-input, 3A synchronous buck with integrated high/low-side FETs; 400kHz–2.1MHz adjustable frequency; 12V fixed option available | Higher efficiency (>95%) and smaller solution size due to synchronous rectification; requires different compensation and layout practices. | Choose LMR14030SDDAR for new designs targeting higher efficiency, smaller footprint, or programmable frequency - but expect redesign effort for loop compensation and EMI filtering. |
Compared with LM2676SX-12, LM2675MX-12 trades output capability and control flexibility for reduced cost and size, while LMR14030SDDAR upgrades to synchronous topology and wider frequency range at the expense of increased design complexity and non-drop-in replacement requirements.
Availability
LM2676SX-12 is available at Aetrix Electronics and suitable for industrial power supplies, smart metering systems, and motor control auxiliary rails requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2676SX-12 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, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2676 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for ease-of-use in cost-sensitive, medium-power industrial and instrumentation applications where minimal external components and fast time-to-market are critical.
FAQ
What is the maximum input voltage rating for the LM2676SX-12?
The absolute maximum input voltage for the LM2676SX-12 is 45V DC, but the recommended operating range is 8V to 40V. Operation above 40V risks exceeding internal device stress limits and may trigger overvoltage protection or reduce long-term reliability. For 40V nominal systems, ensure transient spikes remain below 45V through appropriate input clamping or filtering.
Does the LM2676SX-12 require an external feedback resistor network?
No - the LM2676SX-12 is a fixed 12V output variant and internally configures its feedback reference to 12V. Pin 6 (FB) must be connected directly to the output capacitor's positive terminal; adding external resistors will disrupt regulation and cause overvoltage. This simplifies layout and eliminates resistor tolerance errors affecting output accuracy.
How does the ON/OFF pin function on the LM2676SX-12?
The ON/OFF pin (Pin 7) enables logic-level control: applying ≥1.4V activates regulation, while ≤0.8V forces shutdown with 50µA quiescent current. The pin has an internal 20µA pull-up, so leaving it open defaults to ON. Driving it low with a microcontroller GPIO or optocoupler allows precise system power sequencing - a key feature used in the LM2676SX-12 for standby-aware designs.
What thermal performance can be expected from the LM2676SX-12 in the KTW package?
In the KTW (TO-263-7) package with 0.4896 in² (3.6× package area) of 1 oz copper, the LM2676SX-12 achieves RθJA = 35°C/W. At 3A load and 24VIN, dissipation is ~3.6W - resulting in ~126°C rise above ambient. With 25°C ambient, TJ reaches ~151°C, near thermal shutdown; thus adequate copper area or heatsinking is essential for full-load continuous operation.
Can the LM2676SX-12 be used with ceramic output capacitors?
Yes, but with caution: the LM2676SX-12's internal compensation is optimized for electrolytic/tantalum capacitors with ~20–50mΩ ESR. Using low-ESR ceramics (<5mΩ) may cause instability or excessive output voltage overshoot. If ceramics are required, add a 22–47mΩ damping resistor in series with the capacitor or select a version with ceramic-optimized compensation (e.g., LM2678).
LM2676SX-12 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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- 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-12 FAQ
1.How can I place an order for LM2676SX-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2676SX-12 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-12 reliable?
The price and inventory of LM2676SX-12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2676SX-12 is usually 5 days.
3.What payment methods are accepted for LM2676SX-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2676SX-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2676SX-12?
LM2676SX-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2676SX-12 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-12?
For technical support, including LM2676SX-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2676SX-12 requirements.
6.How does Aetrix verify that LM2676SX-12 is sourced from the original manufacturer or authorized distributors?
All LM2676SX-12 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-12 meets industry standards.
7.What is the process for return or replacement of LM2676SX-12?
All LM2676SX-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2676SX-12, 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-12 part is unused and in its original packaging.
Return procedure for LM2676SX-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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