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Texas Instruments LM2677SX-12/NOPB
- Part No.:
- LM2677SX-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2677SX-12/NOPB.pdf
- Description:
- IC REG BUCK 12V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:252
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Product details
Overview
LM2677SX-12/NOPB from Texas Instruments is a monolithic 5-A step-down (buck) DC/DC voltage regulator with fixed 12-V output, 8 V to 40 V input range, 260-kHz internal oscillator, ±2% output tolerance, and integrated 100-mΩ DMOS power switch. It delivers high-efficiency power conversion in industrial power supplies and battery-charged systems.
For engineers reviewing the LM2677SX-12/NOPB datasheet, LM2677SX-12/NOPB pinout, LM2677SX-12/NOPB application, or LM2677SX-12/NOPB equivalent, key selection criteria include input voltage range compatibility, thermal performance in TO-263-7 package, external sync capability (280–400 kHz), ON/OFF control interface, and fixed-output regulation stability under 5-A load.
Technical Context
The LM2677SX-12/NOPB implements a synchronous-buck topology using an internal high-side DMOS FET switch and external Schottky diode (or optional synchronous rectifier). Its PWM controller operates at a fixed 260-kHz frequency or accepts external synchronization from 280 kHz to 400 kHz, enabling precise ripple frequency control for EMI-sensitive radio and communications equipment.
It integrates thermal shutdown, current limiting (6.1–8.3 A typical), and ON/OFF enable logic with 1.4-V threshold and 50-μA standby current. The feedback pin is internally connected to the 12-V output divider, eliminating external resistors - unlike adjustable versions - and ensuring ±2% output accuracy across –40°C to 125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±2% over full line/load/temperature range - ensures stable rail for downstream analog or digital circuitry without trimming. |
| Input Voltage Range | 8 V to 40 V - supports wide-range industrial inputs, automotive battery systems (cold-crank tolerant), and telecom front-end pre-regulation. |
| Max Output Current | 5 A continuous - enables single-chip supply for FPGA I/O banks, motor drivers, or multi-rail subsystems without parallel devices. |
| Switch RDS(ON) | 0.12 Ω typical at 25°C - minimizes conduction loss and improves efficiency up to 92% at 24-V input/5-A load. |
| Oscillator Frequency | 260 kHz fixed (internal) or 280–400 kHz externally synchronized - allows predictable EMI placement and smaller magnetics when synced. |
| Standby Current | 50 μA max at TJ = 25°C - enables low-power shutdown mode for battery-backed or energy-conscious systems. |
| Operating Junction Temp | –40°C to +125°C - qualified for under-hood automotive, industrial controls, and outdoor embedded applications. |
Pinout & Package
LM2677SX-12/NOPB is packaged in TO-263-7 (KTW), a surface-mount thermally enhanced variant of the DDPAK with exposed thermal pad. Package dimensions are 10.16 mm × 8.69 mm × 4.83 mm (L×W×H), and the DAP must be soldered to a PCB ground plane for thermal and electrical integrity.
| Pin | 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 and Schottky catch diode or sync FET. |
| VIN | Power input | Connects to 8–40 V source and high-frequency input capacitor; path to GND must be shortest possible to minimize switching noise. |
| CB | Bootstrap capacitor terminal | Accepts 0.01-μF ceramic capacitor to VSW - enables gate drive above VIN for high-side MOSFET, critical for low RDS(ON) operation. |
| GND | Power ground | Common return for input/output capacitors, thermal pad, and feedback network - must tie directly to low-impedance ground plane. |
| SYNC | External clock input | Accepts TTL/CMOS signal (≥3 V, 280–400 kHz); open-circuit defaults to 260-kHz internal oscillator - used for EMI control in comms systems. |
| FB | Feedback sense | Internally tied to 12-V output divider - no external resistors required; connects directly to output capacitor for regulation stability. |
| ON/OFF | Enable control input | Logic-high (>1.4 V) enables regulation; ≤0.8 V disables with 50-μA quiescent draw - supports system-level power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100-mΩ DMOS switch | Reduces conduction loss and eliminates need for external high-side FET, simplifying BOM and layout while sustaining >90% efficiency at 5-A load. |
| Fixed 12-V output with no external resistors | Eliminates feedback divider design errors and component tolerance drift - guarantees ±2% output accuracy across temperature and line variations. |
| External sync input (280–400 kHz) | Enables deterministic EMI spectrum positioning and consistent filter design across multiple boards - essential for FCC/CE compliance in radios. |
| Thermal shutdown & current limit | Protects against overload, short-circuit, and ambient overheating without external circuitry - trip thresholds are factory-trimmed and temperature-compensated. |
| 50-μA standby current | Supports ultra-low-power sleep modes in portable or always-on IoT gateways - achieved via internal bias control and ON/OFF pin clamping. |
Applications
| Industrial Power Supply | Battery Charger Pre-regulator |
|---|---|
|
Use Scenario: 24-V industrial bus powering PLC I/O modules requiring clean, regulated 12-V rail. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 24-V bus to stable 12-V output with <1% ripple under dynamic load. Use Value: Delivers 5-A continuous current with 92% efficiency and thermal shutdown - avoids derating or heatsinking in confined enclosures. |
Use Scenario: Li-ion battery charger front-end stage stepping down 36-V solar or adapter input before linear charging IC. IC Role / Device Role / Timing Role: High-efficiency preregulator reducing voltage to 12 V, minimizing heat dissipation in downstream linear charger. Use Value: Fixed 12-V output eliminates feedback tuning; 8–40 V input accommodates variable solar panel or adapter sources. |
| Communications Equipment | Automotive Infotainment System |
|
Use Scenario: 12-V rail generation in LTE base station radio card where EMI must avoid cellular bands. IC Role / Device Role / Timing Role: Synchronized buck converter locked to system clock (300 kHz) to fix ripple frequency outside sensitive RF bands. Use Value: SYNC pin enables precise ripple frequency control - simplifies EMI filter design and passes conducted emissions tests consistently. |
Use Scenario: Central infotainment head unit powered from vehicle battery (9–16 V nominal, up to 40 V load dump). IC Role / Device Role / Timing Role: Robust 12-V supply handling cold-crank (6.5 V) and load-dump (40 V) transients without reset or dropout. Use Value: 8–40 V input range and –40°C to 125°C rating ensure uninterrupted operation across automotive environmental 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 |
|---|---|---|---|
| LM2678-12/NOPB | Same pinout, 65-kHz fixed frequency, lower efficiency (~88%), higher RDS(ON) (0.18 Ω), no SYNC input. | Limited EMI control; suitable only where size/efficiency less critical and sync not needed. | Select LM2678-12/NOPB only if board space allows larger inductor or EMI requirements are relaxed. |
| TPS54560DGQR | 60-V input, 5-A, adjustable output, 100-kHz to 2.5-MHz sync-capable, integrated high/low-side FETs, smaller 10-pin MSOP. | Requires external feedback resistors; supports wider VIN but lacks fixed 12-V option out-of-box. | Choose TPS54560DGQR when input exceeds 40 V or programmable output and higher-frequency sync are required. |
Compared with LM2678-12/NOPB, LM2677SX-12/NOPB offers higher efficiency and EMI control via SYNC; versus TPS54560DGQR, it provides plug-and-play 12-V regulation without resistor selection - trading flexibility for simplicity and proven thermal robustness in TO-263.
Availability
LM2677SX-12/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charger pre-regulators, communications equipment, and automotive infotainment systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2677SX-12/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 designing analog ICs, embedded processors, and power management solutions for industrial, automotive, and communications markets since 1930.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family - engineered for ease of use in high-current DC/DC conversion, emphasizing minimal external components, thermal resilience, and fixed-output reliability in harsh environments.
FAQ
What is the maximum input voltage rating for LM2677SX-12/NOPB?
The absolute maximum input voltage for LM2677SX-12/NOPB is 45 V, but the recommended operating range is 8 V to 40 V per the datasheet. Operation at 40 V is fully characterized for efficiency, thermal performance, and regulation stability - making it suitable for automotive load-dump and industrial 36-V bus applications. Exceeding 40 V risks violating safe operating area limits and triggering overvoltage protection.
Does LM2677SX-12/NOPB require external feedback resistors?
No, LM2677SX-12/NOPB does not require external feedback resistors. As a fixed 12-V output variant, its internal feedback divider is factory-trimmed and connected directly to the FB pin. The FB pin must be wired to the output capacitor's positive terminal - no external resistors or compensation network is needed, simplifying design and improving long-term output accuracy.
Can LM2677SX-12/NOPB synchronize to an external clock?
Yes, LM2677SX-12/NOPB supports external synchronization via its SYNC pin (Pin 5). When driven with a TTL/CMOS-compatible square wave between 280 kHz and 400 kHz, the internal oscillator locks to that frequency - enabling precise control of switching ripple location for EMI filtering. Open-circuiting SYNC reverts to the default 260-kHz internal oscillator.
What thermal considerations apply to LM2677SX-12/NOPB in TO-263-7 package?
LM2677SX-12/NOPB in TO-263-7 (KTW) has a junction-to-ambient thermal resistance (RθJA) of 26°C/W with 1.0064 in² copper pour, dropping to 35°C/W with minimal copper. To sustain 5-A output at 40-V input, the thermal pad must be soldered to ≥1 in² of 1-oz copper with ≥12 thermal vias to inner ground planes. Derating is required above 85°C ambient without forced airflow.
Is LM2677SX-12/NOPB RoHS-compliant and lead-free?
Yes, LM2677SX-12/NOPB is RoHS-compliant and lead-free. The "/NOPB" suffix explicitly denotes "No Lead" (lead-free) packaging per TI's product nomenclature. It meets JEDEC J-STD-020 moisture sensitivity level 3 and is compatible with standard Pb-free reflow profiles - verified in TI's official datasheet revision J (June 2016) and packaging addendum.
LM2677SX-12/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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- 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-12/NOPB FAQ
1.How can I place an order for LM2677SX-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677SX-12/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-12/NOPB reliable?
The price and inventory of LM2677SX-12/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-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2677SX-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677SX-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677SX-12/NOPB?
LM2677SX-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677SX-12/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-12/NOPB?
For technical support, including LM2677SX-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677SX-12/NOPB requirements.
6.How does Aetrix verify that LM2677SX-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2677SX-12/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-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2677SX-12/NOPB?
All LM2677SX-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2677SX-12/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-12/NOPB part is unused and in its original packaging.
Return procedure for LM2677SX-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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