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Texas Instruments LM2677S-ADJ/NOPB
- Part No.:
- LM2677S-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2677S-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:5,319
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Product details
Overview
LM2677S-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC voltage regulator IC with an integrated 100-mΩ DMOS power switch, delivering up to 5 A output current. It supports adjustable output voltages 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 LM2677S-ADJ/NOPB datasheet, LM2677S-ADJ/NOPB pinout, LM2677S-ADJ/NOPB application, or LM2677S-ADJ/NOPB equivalent, key selection criteria include its ±2% output tolerance over line/load/temperature, 260-kHz fixed-frequency oscillator (or external sync up to 400 kHz), thermal shutdown, and ON/OFF control enabling 50-μA standby mode.
Technical Context
The LM2677S-ADJ/NOPB implements a current-mode PWM buck controller with internal 260-kHz oscillator and optional external synchronization (280–400 kHz). Its feedback loop uses a precision 1.21-V reference and two-stage transconductance amplifier, requiring external resistor divider for output setting. The device integrates thermal shutdown, cycle-by-cycle current limiting (6.1–8.75 A), and soft-start via capacitor on FB pin.
It employs bootstrap gate drive (CB pin) for high-side MOSFET enhancement, with dedicated VSW switching node and low-impedance GND paths. The ON/OFF pin provides logic-level enable/disable with 1.4-V threshold and 20-μA pull-up, while SYNC allows deterministic ripple frequency positioning-critical for EMI-sensitive radio and communications systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5 A continuous - supports high-power loads without external pass devices |
| Input Voltage Range | 8 V to 40 V - compatible with 12 V, 24 V, and 36 V industrial/bus rails |
| Output Voltage Range | 1.2 V to 37 V (adjustable) - set via external resistor divider on FB pin |
| Feedback Reference | 1.21 V ±1.2% - enables precise output regulation with minimal drift |
| Switch RDS(on) | 0.14 Ω max at 25°C - minimizes conduction loss and improves thermal performance |
| Efficiency | Up to 92% - achieved via low-RDS(on) switch and optimized control architecture |
| Standby Current | 50 μA - enables ultra-low-power shutdown for battery-backed systems |
Pinout & Package
LM2677S-ADJ/NOPB is packaged in a 7-pin TO-263 (DDPAK) surface-mount package with exposed thermal pad, measuring 10.16 mm × 8.69 mm. The package features low thermal resistance (RθJA = 26°C/W with 1.0064 in² copper) and integrated heatsinking capability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW | Switch node output | Drives external inductor; swings between VIN and ~−0.5 V during off-time - requires low-inductance layout |
| VIN | Power input | Connects to input supply and high-frequency bypass capacitor; path to GND must be shortest possible |
| CB | Bootstrap capacitor connection | Requires 0.01 μF ceramic cap to VSW - enables full enhancement of internal high-side MOSFET |
| GND | Power ground | Common return for CIN, COUT, and internal circuitry - must tie to broad ground plane |
| SYNC | External clock input | Accepts 280–400 kHz TTL/CMOS signal; overrides internal 260-kHz oscillator for EMI control |
| FB | Feedback sense input | Monitors output via resistor divider; 1.21-V reference sets VOUT = 1.21 × (1 + R1/R2) |
| ON/OFF | Enable control input | Logic-high (>1.4 V) enables regulation; <0.8 V disables with 50-μA quiescent draw |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100-mΩ DMOS switch | Eliminates need for external power MOSFET and reduces BOM count and board space |
| ±2% output tolerance | Ensures stable system operation across full temperature and load range without trimming |
| External sync capability (280–400 kHz) | Enables deterministic ripple frequency placement for consistent EMI filtering in comms equipment |
| Thermal shutdown + current limit | Provides robust fault protection during overload, short-circuit, or inadequate heatsinking |
| 50-μA standby current | Supports energy-sensitive applications such as portable instrumentation and remote sensors |
Applications
| Industrial Power Supply | Battery Charger |
|---|---|
Use Scenario: 24-V bus powering 5-V/3.3-V logic rails in PLC I/O modules. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 24 V to tightly regulated 5 V at up to 5 A. Use Value: High efficiency (>90%) reduces thermal load in enclosed cabinets; ±2% tolerance ensures reliable microcontroller operation. | Use Scenario: Charging 12-V sealed lead-acid batteries from variable solar panel output. IC Role / Device Role / Timing Role: Constant-voltage stage regulator with adjustable output set to 13.8 V. Use Value: Wide 8–40 V input accommodates PV array fluctuations; ON/OFF pin enables charge termination control. |
| Communications Equipment | Radiation-Hardened Subsystem |
Use Scenario: Point-of-load conversion in LTE base station RF card with strict EMI limits. IC Role / Device Role / Timing Role: Synchronized buck converter locked to system clock to fix ripple frequency at 350 kHz. Use Value: External SYNC eliminates beat frequencies; 260-kHz base frequency avoids sensitive IF bands. | Use Scenario: Pre-regulator feeding linear LDOs in satellite payload electronics. IC Role / Device Role / Timing Role: High-reliability 5-A intermediate rail generator operating from 28-V spacecraft bus. Use Value: Built-in thermal shutdown and current limit protect downstream analog circuits; −40°C to 125°C rating meets MIL-STD temp range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-ADJ/NOPB | 3-A output, 150-kHz fixed frequency, no SYNC input, higher RDS(on) (0.22 Ω) | Limited to lower-current designs; lacks frequency synchronization for EMI control | Choose when cost sensitivity outweighs current or EMI requirements |
| TPS54560DGQ | 5-A, 100-V input, 2.5–600 kHz adjustable frequency, integrated compensation | Wider input range and programmable frequency but requires more design effort | Prefer when input exceeds 40 V or fine-grained frequency tuning is needed |
Compared with LM2677S-ADJ/NOPB, LM2596S-ADJ/NOPB offers lower cost and simpler layout but sacrifices 40% output current and EMI control; TPS54560DGQ extends input voltage and flexibility at the expense of increased external component count and design complexity.
Availability
LM2677S-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charging systems, and communications equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2677S-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 headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with over 90 years of innovation in power management ICs.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family-designed specifically for ease of use in high-efficiency, medium-power DC-DC conversion where minimal external components and fast time-to-market are critical.
FAQ
What is the maximum output current supported by the LM2677S-ADJ/NOPB?
The LM2677S-ADJ/NOPB delivers up to 5 A of continuous output current under recommended operating conditions (TJ ≤ 125°C, adequate PCB copper area). Peak current limit is specified from 5.75 A to 8.75 A depending on junction temperature, with built-in cycle-by-cycle protection preventing damage during transient overloads. Derating is required above 85°C ambient.
How do I set the output voltage for the LM2677S-ADJ/NOPB?
The LM2677S-ADJ/NOPB uses a resistor divider on the FB pin to set output voltage per VOUT = 1.21 V × (1 + R1/R2), where R2 connects from FB to GND and R1 from VOUT to FB. TI recommends R2 = 2.5 kΩ for stability, yielding R1 = (VOUT/1.21 − 1) × 2.5 kΩ. For example, 5 V requires R1 ≈ 7.83 kΩ. Layout must minimize noise coupling to FB.
Does the LM2677S-ADJ/NOPB support external clock synchronization?
Yes, the LM2677S-ADJ/NOPB supports external clock synchronization via the SYNC pin (Pin 5), accepting TTL/CMOS signals from 280 kHz to 400 kHz. This overrides the internal 260-kHz oscillator and fixes ripple frequency for predictable EMI filtering. A 100-pF capacitor and 1-kΩ pull-down resistor are recommended for AC coupling. Note: current limit foldback is disabled during SYNC operation.
What thermal management considerations apply to the LM2677S-ADJ/NOPB?
The LM2677S-ADJ/NOPB in TO-263 package requires a minimum 1.0064 in² (7.4× package area) of 1-oz copper connected to the exposed thermal pad for RθJA = 26°C/W. Without sufficient copper, junction temperature rises rapidly under 5-A load. Thermal shutdown activates at ~160°C, and derating curves in the datasheet must be followed for continuous operation above 85°C ambient.
Can the LM2677S-ADJ/NOPB be used in battery-powered systems?
Yes, the LM2677S-ADJ/NOPB is well-suited for battery-powered systems due to its 50-μA standby current when disabled via the ON/OFF pin, wide 8–40 V input range (compatible with 12-V and 24-V battery stacks), and high efficiency (>90% at mid-load). Its −40°C to 125°C operating range supports automotive and outdoor deployments. Ensure input UVLO is managed externally if battery voltage drops below 8 V.
LM2677S-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:
- Tube
- 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)
LM2677S-ADJ/NOPB FAQ
1.How can I place an order for LM2677S-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677S-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 LM2677S-ADJ/NOPB reliable?
The price and inventory of LM2677S-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 LM2677S-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2677S-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677S-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677S-ADJ/NOPB?
LM2677S-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677S-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 LM2677S-ADJ/NOPB?
For technical support, including LM2677S-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677S-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2677S-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2677S-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 LM2677S-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2677S-ADJ/NOPB?
All LM2677S-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2677S-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 LM2677S-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2677S-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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