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Texas Instruments LM2677SX-ADJ/NOPB
- Part No.:
- LM2677SX-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2677SX-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,580
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Product details
Overview
LM2677SX-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC voltage regulator IC with integrated 100-mΩ DMOS power switch, delivering up to 5 A output current. It supports adjustable output voltage from 1.2 V to 37 V, operates from 8 V to 40 V input, and achieves up to 92% efficiency in high-power industrial power supplies.
For engineers reviewing the LM2677SX-ADJ/NOPB datasheet, LM2677SX-ADJ/NOPB pinout, LM2677SX-ADJ/NOPB application, or LM2677SX-ADJ/NOPB equivalent, key selection considerations include its 260-kHz fixed-frequency PWM control, external sync capability (280–400 kHz), ±2% output tolerance over line/load/temperature, 50-μA standby current, and thermal shutdown protection.
Technical Context
The LM2677SX-ADJ/NOPB implements a current-mode PWM buck controller with internal 260-kHz oscillator and optional external synchronization. Its DMOS high-side switch drives an external inductor-diode-capacitor power stage, while feedback is sensed via a precision 1.21-V reference amplifier connected to the FB pin.
It features active current limiting (6.1–8.3 A typical), thermal shutdown, ON/OFF enable logic with 1.4-V threshold, and bootstrap gate drive for the high-side FET using a 0.01-μF CB capacitor. The device operates across –40°C to +125°C junction temperature and supports stable regulation under wide input/output transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5 A continuous - supports high-current loads without external current-sharing circuitry |
| Input Voltage Range | 8 V to 40 V - enables direct operation from 12-V/24-V/36-V industrial or automotive battery rails |
| Output Voltage Range | 1.2 V to 37 V (adjustable) - set via external resistor divider on FB pin; 1.21-V reference ensures ±2% accuracy |
| Switching Frequency | 260 kHz (internal) or 280–400 kHz (external sync) - determines inductor size, EMI profile, and ripple frequency placement |
| Efficiency | Up to 92% - achieved via low RDS(on) (0.12 Ω typ) DMOS switch and optimized control architecture |
| Quiescent Current | 6 mA operating / 50 μA standby - enables low-power sleep modes in battery-backed systems |
| Thermal Protection | Integrated thermal shutdown - disables switching above safe junction temperature to prevent damage |
Pinout & Package
LM2677SX-ADJ/NOPB is packaged in a 7-pin TO-263 (DDPAK) surface-mount package with exposed thermal pad. Pin 1 is VSW (switch node), Pin 2 is VIN, Pin 3 is CB (bootstrap capacitor connection), Pin 4 is GND, Pin 5 is SYNC, Pin 6 is FB, and Pin 7 is ON/OFF. The thermal pad must be soldered to a PCB ground plane for thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW (Pin 1) | Switch node output | Drives external inductor; swings between VIN and ~–0.5 V during off-time; requires low-inductance layout |
| VIN (Pin 2) | Main power input | Connects to input bulk capacitor and high-frequency bypass cap; path to GND must be shortest possible |
| CB (Pin 3) | Bootstrap capacitor terminal | Connects 0.01-μF ceramic cap to VSW; provides gate drive voltage > VIN for high-side FET turn-on |
| GND (Pin 4) | Power ground | System ground reference for all internal circuits; must tie directly to thermal pad and input/output capacitors |
| SYNC (Pin 5) | External clock input | Accepts TTL/CMOS clock (280–400 kHz); overrides internal 260-kHz oscillator for EMI control or system synchronization |
| FB (Pin 6) | Feedback sense input | Connects to resistor divider; regulates output by comparing to internal 1.21-V reference; bias current < 100 nA |
| ON/OFF (Pin 7) | Enable/disable control | Logic-high (>1.4 V) enables regulation; logic-low (<0.8 V) forces 50-μA standby mode; internal 20-μA pull-up |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100-mΩ DMOS switch | Eliminates need for external high-side MOSFET and driver, reducing BOM count and layout complexity |
| ±2% output voltage tolerance | Ensures precise regulation across full line, load, and temperature range without post-production trimming |
| External sync capability (280–400 kHz) | Enables deterministic ripple frequency positioning for EMI filtering and multi-rail system clock alignment |
| 50-μA standby quiescent current | Supports ultra-low-power sleep states in portable or always-on industrial controllers |
| Thermal shutdown + current limit | Provides autonomous fault protection without external monitoring circuitry |
Applications
| Industrial Power Supply | Battery Charger Controller |
|---|---|
Use Scenario: 24-V input rail powering 5-V/3.3-V logic and 12-V actuators in PLC backplanes. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator providing stable 5-A output with tight line/load regulation. Use Value: High efficiency (>90%) reduces thermal load in enclosed cabinets; wide 8–40 V input accommodates brownout and surge conditions. | Use Scenario: Charging 12-V sealed lead-acid or LiFePO₄ battery packs from variable solar or vehicle sources. IC Role / Device Role / Timing Role: Constant-voltage/constant-current preregulator stage before linear charge management IC. Use Value: Adjustable output allows precise battery voltage setting; current limit protects battery during bulk charge phase. |
| Communications Equipment | Ruggedized Embedded System |
Use Scenario: RF transceiver board requiring clean, synchronized 5-V supply to minimize spectral noise coupling. IC Role / Device Role / Timing Role: Synchronized buck converter locked to system master clock to fix ripple at known frequency. Use Value: External SYNC input enables ripple frequency placement away from sensitive IF bands; 260-kHz base frequency avoids AM radio band. | Use Scenario: Fanless edge computing module operating in –40°C to +85°C ambient with no forced airflow. IC Role / Device Role / Timing Role: Main 5-V/5-A power rail generator with thermal shutdown and wide-temp operation. Use Value: TO-263 package with thermal pad enables conduction cooling; –40°C to +125°C rating ensures reliability in uncontrolled environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678-5.0/NOPB | Fixed 5-V output; same package, pinout, and 5-A rating; lacks adjustability and external sync | Suitable only where 5-V output is fixed and no frequency synchronization needed | Select when design requires simplified feedback (no resistor divider) and no programmable output voltage |
| LM2596-ADJ | 3-A rated; lower RDS(on) (0.16 Ω); no external sync; 150-kHz switching; smaller TO-220 package | Limited to 3-A loads; less efficient at high current; no EMI control via sync | Choose for cost-sensitive, lower-current designs where footprint and thermal margin allow |
Compared with LM2678-5.0/NOPB, LM2677SX-ADJ/NOPB offers output voltage flexibility and EMI control via sync; compared with LM2596-ADJ, it delivers higher current, better efficiency at 5 A, and wider input range - making it optimal for demanding industrial and communications power rails.
Availability
LM2677SX-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charging systems, and ruggedized embedded electronics requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2677SX-ADJ/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 leadership in high-reliability industrial and automotive solutions.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family of integrated DC-DC regulators, designed specifically for ease-of-use, minimal external component count, and robust performance in harsh industrial environments.
FAQ
What is the maximum output current supported by the LM2677SX-ADJ/NOPB?
The LM2677SX-ADJ/NOPB supports up to 5 A of continuous output current under recommended operating conditions (TJ ≤ 125°C, adequate PCB copper area). Its internal DMOS switch has a typical RDS(on) of 0.12 Ω, enabling high-current operation with minimal conduction loss. Derating is required at elevated ambient temperatures or with limited thermal dissipation.
How do I configure the output voltage for the LM2677SX-ADJ/NOPB?
The LM2677SX-ADJ/NOPB uses a resistor divider from output to FB pin and from FB pin to GND to set output voltage. With a precise 1.21-V internal reference, VOUT = 1.21 × (1 + R1/R2). For example, R2 = 2.5 kΩ and R1 = 7.83 kΩ yields 5 V. Layout must avoid noise coupling into the FB trace, and R1/R2 should be ≤ 500 kΩ total to limit bias current error.
Does the LM2677SX-ADJ/NOPB support external clock synchronization?
Yes, the LM2677SX-ADJ/NOPB supports external synchronization via the SYNC pin (Pin 5). An externally applied TTL/CMOS clock signal between 280 kHz and 400 kHz overrides the internal 260-kHz oscillator. This allows precise control of switching frequency for EMI mitigation or system-level timing alignment - a feature not present in lower-tier regulators like the LM2596.
What thermal management is required for reliable operation of the LM2677SX-ADJ/NOPB?
The LM2677SX-ADJ/NOPB in TO-263 (KTW) package requires connection of its exposed thermal pad to a minimum 0.4896 in² (3.6× package area) copper pour on the PCB for RθJA ≈ 35°C/W. Without sufficient copper, junction temperature may exceed 125°C under 5-A load. Thermal shutdown activates above this threshold, but sustained operation near limits degrades long-term reliability.
Can the LM2677SX-ADJ/NOPB be used in battery-powered systems with low standby power requirements?
Yes, the LM2677SX-ADJ/NOPB draws only 50 μA in shutdown mode when the ON/OFF pin is pulled below 0.8 V. In active operation, quiescent current is typically 6 mA - low enough for many battery-backed applications. Combined with its wide 8–40 V input range, it supports direct integration into 12-V or 24-V battery systems with intelligent power sequencing.
LM2677SX-ADJ/NOPB 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:
- Active
- 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):
- 1.21V
- Voltage - Output (Max):
- 37V
- 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)
LM2677SX-ADJ/NOPB FAQ
1.How can I place an order for LM2677SX-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677SX-ADJ/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 LM2677SX-ADJ/NOPB reliable?
The price and inventory of LM2677SX-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2677SX-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2677SX-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677SX-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677SX-ADJ/NOPB?
LM2677SX-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677SX-ADJ/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 LM2677SX-ADJ/NOPB?
For technical support, including LM2677SX-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677SX-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2677SX-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2677SX-ADJ/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 LM2677SX-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2677SX-ADJ/NOPB?
All LM2677SX-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2677SX-ADJ/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 LM2677SX-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2677SX-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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