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Texas Instruments LM2677S-12/NOPB
- Part No.:
- LM2677S-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2677S-12/NOPB.pdf
- Description:
- IC REG BUCK 12V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,097
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Product details
Overview
LM2677S-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 - used in high-efficiency industrial power supplies and battery-charged systems.
For engineers reviewing the LM2677S-12/NOPB datasheet, LM2677S-12/NOPB pinout, LM2677S-12/NOPB application, or LM2677S-12/NOPB equivalent, key selection considerations include input voltage headroom, thermal management under 5-A load, external sync capability (280–400 kHz), bootstrap capacitor design (0.01 µF), and ON/OFF control interface for standby current of 50 µA.
Technical Context
The LM2677S-12/NOPB implements a synchronous-buck topology using an internal N-channel DMOS switch and external Schottky diode (or optional synchronous rectifier), with PWM control driven by a 260-kHz fixed-frequency oscillator or externally synchronized clock (280–400 kHz). Its feedback loop references a precision 1.21-V internal bandgap and achieves regulation via a two-stage transconductance amplifier.
It integrates thermal shutdown, cycle-by-cycle current limiting (6.1–8.3 A), and ON/OFF enable logic with 1.4-V threshold. The device operates across –40°C to 125°C junction temperature and supports stable operation with minimum 0.01-µF bootstrap capacitor and 100-mA to 5-A load range while maintaining ±2% output accuracy over line and load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±2% over full line/load/temperature - ensures stable rail for downstream logic, analog circuitry, or motor drivers without external resistor divider. |
| Input Voltage Range | 8 V to 40 V - supports wide-input industrial, automotive, and telecom power buses including 12-V, 24-V, and 36-V nominal systems. |
| Max Output Current | 5 A continuous - enables single-regulator solutions for mid-power subsystems without parallel devices or heatsink oversizing. |
| Switch RDS(on) | 0.12 Ω typical at 25°C - minimizes conduction loss and contributes to >92% efficiency at 24-VIN/5-AOUT. |
| Oscillator Frequency | 260 kHz fixed (225–280 kHz over temp) - sets fundamental ripple frequency; allows use of standard off-the-shelf inductors and simplifies EMI filter design. |
| Standby Quiescent Current | 50 µA max at 25°C - enables low-power sleep modes in battery-backed or energy-conscious applications. |
| Current Limit Threshold | 6.1–8.3 A (temp-dependent) - provides robust short-circuit protection while allowing peak transient loads above 5 A. |
Pinout & Package
LM2677S-12/NOPB is packaged in TO-263 (KTW) - a 7-pin surface-mount package with exposed thermal pad (10.16 mm × 8.69 mm body), optimized for high-current thermal dissipation on PCB copper planes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW | Switch node output | Drives external inductor; swings between VIN and ~–0.5 V (Schottky drop); requires low-inductance layout to minimize ringing and EMI. |
| VIN | Main power input | Connects to input bulk capacitor and high-frequency bypass cap; path to GND must be shortest possible to reduce switching noise coupling. |
| CB | Bootstrap capacitor connection | Accepts 0.01-µF ceramic capacitor to VSW; supplies gate drive voltage >VIN for internal high-side MOSFET turn-on. |
| GND | Power ground | Common return for input/output capacitors, feedback network, and thermal pad; must connect directly to large copper plane. |
| SYNC | External clock input | Accepts TTL/CMOS clock (280–400 kHz); overrides internal oscillator; disables current-limit foldback when active. |
| FB | Feedback sense | Internally connected to 12-V output divider; no external resistors required - simplifies layout and eliminates trimming errors. |
| ON/OFF | Enable control input | Logic-high (>1.4 V) enables regulation; logic-low (<0.8 V) forces 50-µA standby mode; internal 20-µA pullup allows floating for always-on operation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100-mΩ DMOS switch | Enables >92% efficiency at 24-VIN/12-VOUT/5-A without external MOSFETs - reduces BOM count and layout complexity. |
| ±2% output voltage tolerance | Guaranteed over full temperature and load range - eliminates need for post-production calibration in precision 12-V rail applications. |
| External sync capability (280–400 kHz) | Allows precise ripple frequency positioning for EMI compliance and avoids sensitive bands in radio/comm systems. |
| Thermal shutdown + current limit | Protects against sustained overload or ambient overheating; latches off until reset by cycling ON/OFF or VIN. |
| 50-µA standby quiescent current | Supports ultra-low-power system sleep states - critical for battery-powered telemetry, remote sensors, and backup systems. |
Applications
| Industrial Power Supply | Battery Charger Pre-regulator |
|---|---|
|
Use Scenario: Converts unregulated 24-V DC bus to stable 12-V rail powering PLC I/O modules, sensor interfaces, and relay drivers. IC Role / Device Role / Timing Role: Primary buck regulator delivering 5-A continuous current with tight line/load regulation and thermal robustness. Use Value: Eliminates need for linear preregulation; maintains ±2% output accuracy across –40°C to 85°C ambient without derating. |
Use Scenario: Steps down variable 30–40-V battery charger output to fixed 12-V supply for charge management ICs and status LEDs. IC Role / Device Role / Timing Role: High-efficiency intermediate regulator ensuring clean, ripple-controlled 12-V bias under dynamic load transients. Use Value: Achieves >92% efficiency at 24-VIN, reducing heat rise in enclosed charger enclosures and extending thermal margin. |
| Communications Equipment | Test & Measurement Instrumentation |
|
Use Scenario: Powers RF front-end stages and baseband processors in portable radios where EMI-sensitive operation demands controlled switching frequency. IC Role / Device Role / Timing Role: Synchronized buck converter locked to system clock (280–400 kHz) to fix ripple spectrum and simplify filtering. Use Value: External SYNC input enables deterministic EMI placement - meeting CISPR-22 Class B limits without iterative board rework. |
Use Scenario: Supplies precision 12-V analog rails for ADC reference buffers, op-amp signal chains, and DAC output stages. IC Role / Device Role / Timing Role: Low-noise, tightly regulated DC source with minimal load-induced drift and fast transient response. Use Value: ±2% output tolerance and <100-mV load-step ripple (500 mA → 5 A) preserve measurement accuracy and SNR integrity. |
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, identical 12-V fixed output, but uses external NPN transistor instead of integrated DMOS switch - requires external switch, driver, and higher component count. | Lacks integrated power switch; lower efficiency (~85%) and larger solution size; suitable only where discrete switch control is required. | Select LM2678-12/NOPB only if discrete switch timing or fault isolation is mandatory; otherwise LM2677S-12/NOPB offers superior integration and efficiency. |
| TPS54560DGQR | 60-V input, 5-A adjustable-output buck with integrated 110-mΩ FET, 100-kHz–2.5-MHz sync range, and enhanced light-load efficiency (PFM mode). | Broader input range and programmable output; lacks fixed 12-V option - requires external feedback resistors and adds design overhead. | Choose TPS54560DGQR for >40-V input or variable output needs; LM2677S-12/NOPB remains optimal for cost-sensitive, fixed 12-V, 8–40-V applications. |
Compared with LM2678-12/NOPB, LM2677S-12/NOPB delivers higher efficiency and smaller footprint via integrated DMOS; compared with TPS54560DGQR, it offers simpler fixed-output implementation and lower BOM cost - making it ideal for dedicated 12-V industrial and communications power rails.
Availability
LM2677S-12/NOPB is available at Aetrix Electronics and suitable for industrial automation, battery charging systems, and communications equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2677S-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 company specializing in analog, embedded processing, and power management technologies, with decades of leadership in high-reliability power conversion ICs.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use, minimal external component count, and robust performance in industrial, automotive, and telecom power applications.
FAQ
What is the maximum input voltage rating for LM2677S-12/NOPB?
The absolute maximum input voltage for LM2677S-12/NOPB is 45 V, but the recommended operating range is 8 V to 40 V. Operation above 40 V risks exceeding safe operating area limits and may trigger thermal shutdown or damage the internal DMOS switch. Always maintain ≥1-V margin below 45 V in transient conditions, and verify with input clamping or pre-regulation for 42-V automotive or industrial sources.
Does LM2677S-12/NOPB require external feedback resistors?
No, LM2677S-12/NOPB does not require external feedback resistors. It is a fixed 12-V output variant with internal resistor divider connected to the FB pin, so the FB pin is tied directly to the output capacitor. This eliminates resistor tolerance errors and simplifies layout - unlike the adjustable LM2677 versions which require external R1/R2 networks.
Can LM2677S-12/NOPB synchronize to an external clock?
Yes, LM2677S-12/NOPB supports external synchronization via its SYNC pin (Pin 5), accepting TTL/CMOS-compatible clocks from 280 kHz to 400 kHz. When driven, the internal 260-kHz oscillator is overridden, enabling precise ripple frequency control - essential for EMI-sensitive applications like radio transceivers and test equipment.
What is the thermal resistance (RθJA) of LM2677S-12/NOPB in TO-263 package?
In the TO-263 (KTW) package, LM2677S-12/NOPB has a junction-to-ambient thermal resistance of 26°C/W when mounted on 1.0064 in² (7.4× package area) of 1-oz copper. With minimal copper (0.136 in²), RθJA rises to 56°C/W. Proper thermal pad soldering and adequate PCB copper area are mandatory to sustain 5-A output at 125°C junction temperature.
How does the ON/OFF pin function on LM2677S-12/NOPB?
The ON/OFF pin (Pin 7) enables or disables LM2677S-12/NOPB regulation: voltage >1.4 V enables operation; <0.8 V forces shutdown with 50-µA standby current. The pin features an internal 20-µA pullup, so leaving it floating defaults to ON. Driving it low with a microcontroller GPIO provides clean, low-power system-level control without external circuitry.
LM2677S-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:
- Bulk
- 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)
LM2677S-12/NOPB FAQ
1.How can I place an order for LM2677S-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677S-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 LM2677S-12/NOPB reliable?
The price and inventory of LM2677S-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 LM2677S-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2677S-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677S-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677S-12/NOPB?
LM2677S-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677S-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 LM2677S-12/NOPB?
For technical support, including LM2677S-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677S-12/NOPB requirements.
6.How does Aetrix verify that LM2677S-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2677S-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 LM2677S-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2677S-12/NOPB?
All LM2677S-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2677S-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 LM2677S-12/NOPB part is unused and in its original packaging.
Return procedure for LM2677S-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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