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Texas Instruments LM2677SDX-ADJ/NOPB
- Part No.:
- LM2677SDX-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2677SDX-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,711
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Product details
Overview
LM2677SDX-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 across an adjustable output range of 1.2 V to 37 V. It operates from 8 V to 40 V input, achieves up to 92% efficiency, and features ±2% output voltage tolerance over full line/load/temperature conditions. It is used in high-efficiency pre-regulators for industrial power systems.
For engineers reviewing the LM2677SDX-ADJ/NOPB datasheet, LM2677SDX-ADJ/NOPB pinout, LM2677SDX-ADJ/NOPB application, or LM2677SDX-ADJ/NOPB equivalent, key selection criteria include its adjustable output capability, internal 260 kHz oscillator, external sync clock support (280–400 kHz), ON/OFF control with 50 µA standby current, and thermal shutdown protection.
Technical Context
The LM2677SDX-ADJ/NOPB implements a fixed-frequency PWM buck controller with internal current-mode regulation and cycle-by-cycle current limiting. Its feedback loop uses a precision 1.21 V reference (VFB = 1.186–1.234 V) to set output voltage via external resistor divider, enabling stable 1.2–37 V adjustment. The device integrates a low-RDS(on) (0.12–0.225 Ω) DMOS switch and supports both internal oscillation and external synchronization.
It features active thermal shutdown, overcurrent protection with 5.75–8.75 A current limit, and ON/OFF control with 0.8–2.0 V threshold. The BOOST capacitor (0.01 µF) enables gate overdrive for optimal switch conduction, while SYNC pin allows precise ripple frequency control-critical for EMI-sensitive communications equipment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8 V to 40 V - supports wide-range unregulated supplies including 12 V, 24 V, and 36 V industrial rails. |
| Output Voltage Range | 1.2 V to 37 V (adjustable) - set via external resistor divider; enables single BOM for multiple output requirements. |
| Max Output Current | 5 A - continuous load capability with internal current limit (5.75–8.75 A) and thermal shutdown. |
| Switch RDS(on) | 0.12–0.225 Ω - low conduction loss ensures >90% efficiency at 5 A, reducing heatsink requirements. |
| Oscillator Frequency | 260 kHz (internal) or 280–400 kHz (external sync) - enables consistent EMI filtering and predictable ripple placement. |
| Feedback Reference | 1.186–1.234 V - tight tolerance enables ±2% output accuracy without trimming, simplifying production calibration. |
| Standby Current | 50 µA - ultra-low quiescent draw during ON/OFF disable, suitable for battery-backed or energy-sensitive systems. |
Pinout & Package
The LM2677SDX-ADJ/NOPB is housed in a 7-pin DDPAK/TO-263 (KTW) package with exposed thermal pad (DAP) for enhanced heat dissipation. Thermal resistance ranges from 26 °C/W (with 7.4× paddle copper area) to 56 °C/W (minimal copper), supporting high-power operation without forced air.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW (Pin 1) | Switch Node | Drives external inductor; swings between VIN and ~−0.5 V (Schottky drop); requires low-inductance layout. |
| VIN (Pin 2) | Main Input Supply | Provides bias and power; must be bypassed with ≥10 µF low-ESR capacitor near pin. |
| CBOOST (Pin 3) | Bootstrap Capacitor | 0.01 µF ceramic connects to VSW; enables full gate drive for low RDS(on). |
| GND (Pin 4) | Power Ground | Common return for switch, feedback, and control circuits; requires solid ground plane. |
| SYNC (Pin 5) | External Clock Input | Accepts TTL/CMOS clock (280–400 kHz); resets internal oscillator on rising edge. |
| FB (Pin 6) | Feedback Input | Connects to resistor divider; regulates output by comparing to 1.21 V internal reference. |
| ON/OFF (Pin 7) | Enable Control | Logic-level shutdown: <0.8 V disables regulator; draws only 50 µA in standby. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100 mΩ DMOS Switch | Eliminates need for external MOSFET and driver; reduces BOM count and layout complexity. |
| Adjustable Output (1.2–37 V) | Single part replaces multiple fixed-output regulators; supports flexible system-level voltage scaling. |
| External Sync Capability (280–400 kHz) | Enables deterministic EMI spectrum positioning and synchronized multi-rail filtering in dense PCBs. |
| Thermal Shutdown + Current Limit | Protects against overload and ambient overheating without external sensing components. |
| ON/OFF Pin with 50 µA Standby | Allows system-level power sequencing and low-power sleep modes without auxiliary circuitry. |
Applications
| Industrial Power Pre-regulator | Battery Charger Front-end |
|---|---|
Use Scenario: Converts 24 V or 36 V bus to 5 V/3.3 V intermediate rail for downstream LDOs or point-of-load converters. IC Role / Device Role / Timing Role: Primary step-down regulator providing stable, high-current intermediate voltage with minimal external components. Use Value: Delivers >90% efficiency at 5 A, reducing thermal load and eliminating need for heatsinks in compact enclosures. | Use Scenario: Regulates variable-input battery charging systems (e.g., lead-acid or LiFePO4) requiring programmable constant-voltage output. IC Role / Device Role / Timing Role: Adjustable buck controller setting precise charge voltage via FB divider; supports thermal foldback during high-temp charging. Use Value: ±2% output tolerance ensures accurate battery termination voltage; 5 A capability supports fast-charging profiles up to 25 W. |
| Communications Equipment PSU | Ruggedized Embedded System Supply |
Use Scenario: Powers RF transceivers and baseband processors in cellular infrastructure or two-way radios where EMI compliance is critical. IC Role / Device Role / Timing Role: Synchronized buck regulator locked to system clock to fix ripple frequency and simplify EMI filter design. Use Value: External SYNC (280–400 kHz) enables repeatable noise spectrum, easing FCC/CE certification and reducing filter component count. | Use Scenario: Supplies mission-critical embedded controllers in transportation or energy monitoring systems operating from 12–36 V vehicle/industrial buses. IC Role / Device Role / Timing Role: Robust primary DC/DC converter with −40°C to +125°C junction rating and built-in fault protection. Use Value: Thermal shutdown and current limit ensure reliable operation under sustained overload or ambient temperature extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678SDX-ADJ/NOPB | Higher 8 A current rating; same 8–40 V input and 1.2–37 V adjustable output; 260 kHz fixed frequency only (no SYNC). | Preferred where higher output current is required and EMI synchronization is not needed. | Select when 5 A margin is insufficient and board space allows larger inductor/capacitor sizing. |
| TPS54560DGQR | 4.5–60 V input; 5 A output; 100 kHz–2.5 MHz adjustable switching frequency; integrated soft-start and UVLO. | Better suited for wide-input automotive or solar applications; lacks built-in thermal shutdown flag. | Choose for designs needing wider VIN range, programmable frequency, or tighter startup control-not for drop-in replacement. |
Compared with LM2677SDX-ADJ/NOPB, LM2678SDX-ADJ/NOPB offers higher current headroom but sacrifices sync capability, while TPS54560DGQR provides broader input range and frequency flexibility at the cost of added external component dependencies and no integrated thermal fault reporting.
Availability
LM2677SDX-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power pre-regulators, battery charger front-ends, communications equipment PSUs, and ruggedized embedded system supplies requiring stable component supply and long-term manufacturability.
Supply support for LM2677SDX-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 leader specializing in analog, embedded processing, and power management technologies with decades of expertise in high-reliability power conversion ICs.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family-designed specifically for easy-to-implement, high-efficiency buck regulators using minimal external components and standard off-the-shelf magnetics.
FAQ
What is the recommended boost capacitor value for LM2677SDX-ADJ/NOPB?
The LM2677SDX-ADJ/NOPB requires a 0.01 µF ceramic capacitor rated for ≥50 V between the BOOST (Pin 3) and VSW (Pin 1) terminals. This capacitor enables gate overdrive of the internal DMOS switch, ensuring low RDS(on) and high efficiency. TI specifies this value across all operating conditions and does not recommend deviation unless validated per AN-1187 layout guidelines.
Can LM2677SDX-ADJ/NOPB operate with input voltage below 8 V?
No. The absolute minimum operating input voltage for LM2677SDX-ADJ/NOPB is 8 V, as specified in the Absolute Maximum Ratings and Operating Ratings tables. Operation below 8 V may result in failure to start, unstable regulation, or undefined behavior. The device is not characterized for sub-8 V operation, and TI does not guarantee performance outside the 8–40 V range.
How is output voltage set on LM2677SDX-ADJ/NOPB?
LM2677SDX-ADJ/NOPB uses a resistor divider from output to FB (Pin 6) and GND to set output voltage based on its internal 1.21 V feedback reference. The formula is VOUT = 1.21 × (1 + R1/R2), where R1 connects to VOUT and R2 to GND. TI recommends using 1% tolerance resistors and routing the FB trace away from noisy nodes to maintain ±2% output accuracy.
Does LM2677SDX-ADJ/NOPB support forced continuous conduction mode (FCCM)?
No. LM2677SDX-ADJ/NOPB operates in pulse-width modulation (PWM) mode with inherent discontinuous conduction mode (DCM) at light loads. It does not include a dedicated FCCM pin or internal circuitry to force continuous mode. Efficiency drops slightly below ~10% load due to DCM transition, but no external control is available to override this behavior.
What thermal considerations apply to LM2677SDX-ADJ/NOPB in the KTW package?
LM2677SDX-ADJ/NOPB in the DDPAK/TO-263 (KTW) package requires connection of the exposed die attach pad (DAP) to a PCB ground plane for effective heat transfer. With 1.0064 in² copper area and 12 vias, θJA drops to 26 °C/W. Without proper DAP grounding, junction temperature can exceed 125°C at 5 A, triggering thermal shutdown. TI Application Note AN-1187 provides exact layout rules.
LM2677SDX-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- 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):
- 1.21V
- 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:
- 14-VSON (5x6)
LM2677SDX-ADJ/NOPB FAQ
1.How can I place an order for LM2677SDX-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677SDX-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 LM2677SDX-ADJ/NOPB reliable?
The price and inventory of LM2677SDX-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 LM2677SDX-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2677SDX-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677SDX-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677SDX-ADJ/NOPB?
LM2677SDX-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677SDX-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 LM2677SDX-ADJ/NOPB?
For technical support, including LM2677SDX-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677SDX-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2677SDX-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2677SDX-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 LM2677SDX-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2677SDX-ADJ/NOPB?
All LM2677SDX-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2677SDX-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 LM2677SDX-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2677SDX-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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