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Texas Instruments LM2677S-12
- Part No.:
- LM2677S-12
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2677S-12.pdf
- Description:
- IC REG BUCK 12V 5A TO263
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM2677S-12 from Texas Instruments is a monolithic step-down (buck) DC/DC voltage regulator with integrated 100 mΩ DMOS power switch, delivering up to 5A output current at fixed 12V output, operating from 15V to 40V input, achieving up to 92% efficiency at 24VIN/5A, and used in high-efficiency pre-regulator and battery-charger applications.
For engineers reviewing the LM2677S-12 datasheet, LM2677S-12 pinout, LM2677S-12 application, or LM2677S-12 equivalent, key selection criteria include input voltage range (15–40V), ±2% output tolerance over line/load/temperature, 260 kHz fixed-frequency operation, thermal shutdown protection, and ON/OFF control with 50 μA standby current.
Technical Context
The LM2677S-12 implements a current-mode PWM buck controller with internal 260 kHz oscillator, fixed 12V feedback reference, and cycle-by-cycle current limiting. Its DMOS switch supports continuous 5A output with RDS(ON) = 0.12 Ω (typ), enabling high-efficiency conversion without external gate drivers.
It features synchronous clock input (280–400 kHz), adjustable soft-start via external capacitor on FB pin, and built-in thermal shutdown with automatic recovery. The device operates across −40°C to +125°C junction temperature and supports both TO-220 (NDZ) and DDPAK/TO-263 (KTW) packages with validated thermal resistance down to 26°C/W (KTW, 7.4× copper area).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±2% over full line, load, and temperature (11.76–12.24 V); eliminates need for external feedback resistors. |
| Input Voltage Range | 15 V to 40 V (min 15 V ensures stable regulation at 12 V output); absolute max 45 V. |
| Output Current | Up to 5 A continuous; current limit threshold 5.75–8.75 A (typ 6.1 A) with foldback disabled during sync mode. |
| Efficiency | Up to 92% at VIN = 24 V, IOUT = 5 A; enabled by low RDS(ON) (0.12 Ω typ) DMOS switch and optimized control loop. |
| Switching Frequency | 260 kHz fixed internal oscillator (225–280 kHz range); externally synchronizable to 280–400 kHz for EMI control and ripple filtering. |
| Quiescent Current | 4.2 mA typical operating IQ; drops to 50 μA in standby when ON/OFF pin < 0.8 V. |
| Thermal Protection | Internal thermal shutdown with hysteresis; recovers automatically after junction cools below safe threshold. |
Pinout & Package
LM2677S-12 is available in TO-220 (NDZ0007B, 7-lead) and DDPAK/TO-263 (KTW0007B, 7-lead) packages. Both feature exposed thermal pad (DAP) for enhanced heat dissipation; KTW package achieves θJA = 26°C/W with 7.4× copper area.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 2) | Power input | Accepts 15–40 V DC; requires local 0.1–0.47 μF ceramic + bulk capacitor; supplies internal bias and switch current. |
| VSW (Pin 1 & 4) | Switch node | Drives external catch diode and inductor; swings from VIN to ~−0.5 V (Schottky drop); connects to CBOOST. |
| CBOOST (Pin 3) | Bootstrap capacitor terminal | Connects 0.01 μF/50 V ceramic capacitor to VSW; enables full gate drive for low RDS(ON) operation. |
| GND (Pin 5) | Power ground | Primary return path for switch current and IC bias; requires low-inductance PCB ground plane. |
| SYNC (Pin 5, alternate function) | External clock input | Accepts TTL/CMOS clock (280–400 kHz); AC-coupled via 100 pF + 1 kΩ to GND; disables current limit foldback. |
| FB (Pin 6) | Feedback input | Internally connected to 12 V divider; direct connection to output required; no external resistors needed. |
| ON/OFF (Pin 7) | Enable/disable control | Logic-low (< 0.8 V) disables regulator; draws only 50 μA standby current; internal 20 μA pull-up. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100 mΩ DMOS switch | Enables 5 A continuous output without external MOSFET; reduces BOM count and layout complexity. |
| ±2% output voltage tolerance | Guaranteed over full line (15–40 V), load (100 mA–5 A), and temperature (−40°C to +125°C); eliminates post-production trimming. |
| 260 kHz fixed-frequency PWM | Provides predictable EMI profile and simplifies filter design; allows use of standard off-the-shelf inductors (e.g., 10 μH). |
| External synchronization capability | Supports precise ripple frequency control (280–400 kHz) for consistent EMI filtering in communications equipment. |
| Thermal shutdown + current limiting | Protects against overload and ambient overheating; auto-recovery prevents latch-up during transient faults. |
| 50 μA standby quiescent current | Enables low-power system sleep modes; critical for battery-powered chargers and portable industrial devices. |
Applications
| Industrial Power Pre-regulation | Battery Charging Systems |
|---|---|
|
Use Scenario: Converting unregulated 24 V or 36 V bus to stable 12 V for downstream linear regulators or digital logic rails. IC Role / Device Role / Timing Role: Primary step-down regulator providing clean, high-current 12 V supply with minimal external components. Use Value: Delivers 92% efficiency at 24 VIN/5 A, reducing thermal load vs. linear solutions and eliminating need for heatsinks in compact enclosures. |
Use Scenario: Charging 12 V sealed lead-acid or LiFePO4 battery packs from variable-input solar or vehicle alternator sources. IC Role / Device Role / Timing Role: Constant-voltage stage regulator maintaining precise 12.0 V ±2% during bulk charge phase. Use Value: Fixed 12 V output with tight tolerance ensures optimal battery voltage compliance; ON/OFF pin enables charge termination control. |
| Communications Equipment Power | Ruggedized Embedded Systems |
|
Use Scenario: Supplying 12 V to RF power amplifiers, transceivers, or baseband processors in cellular infrastructure or two-way radios. IC Role / Device Role / Timing Role: EMI-controlled power source synchronized to system clock to avoid spectral interference in sensitive receive bands. Use Value: SYNC pin allows locking switching frequency to 300 kHz or 350 kHz, positioning ripple outside critical IF or LO bands. |
Use Scenario: Providing main 12 V rail in transportation, energy metering, or factory automation controllers operating in −40°C to +85°C ambient. IC Role / Device Role / Timing Role: High-reliability buck regulator with thermal shutdown and wide input range for harsh environments. Use Value: −40°C to +125°C junction rating and robust current limiting ensure uninterrupted operation under voltage surges and thermal stress. |
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 | Same pinout, identical 12 V fixed output, but rated for 3 A (vs. 5 A); lower RDS(ON) (0.15 Ω) and reduced thermal capability. | Suitable for ≤3 A loads where board space or cost constraints preclude using 5 A part; not recommended for sustained >3 A operation. | Select LM2678-12 only if load current remains ≤3 A and thermal margin is verified with smaller copper area. |
| LM5009AM-12 | Higher input range (4.5–100 V), 1.5 A output, 1 MHz switching, smaller SOIC-8 package; no SYNC or thermal pad. | Designed for wide-input, low-current, space-constrained applications; lacks 5 A capability and thermal robustness of LM2677S-12. | Choose LM5009AM-12 only for ultra-wide input (e.g., 12–72 V battery systems) with <1.5 A loads and no thermal pad requirement. |
Compared with LM2678-12 and LM5009AM-12, the LM2677S-12 uniquely delivers 5 A continuous output with integrated thermal pad, fixed 12 V accuracy, and SYNC capability-making it the only option among the three qualified for high-current, thermally demanding, and EMI-sensitive 12 V buck applications.
Availability
LM2677S-12 is available at Aetrix Electronics and suitable for industrial power pre-regulation, battery charging systems, communications equipment power, ruggedized embedded systems, and high-reliability DC/DC conversion requiring stable component supply across extended temperature and long-lifecycle programs.
Supply support for LM2677S-12 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 ICs, with decades of expertise in high-efficiency switching regulators and industrial-grade power solutions.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family-designed specifically for easy-to-implement, high-reliability buck converters requiring minimal external components and guaranteed performance across harsh operating conditions.
FAQ
What is the minimum input voltage required for stable 12 V output from the LM2677S-12?
The LM2677S-12 requires a minimum input voltage of 15 V to maintain regulated 12 V output across full load and temperature. This headroom ensures sufficient duty cycle margin for the internal PWM controller and avoids dropout during line transients or thermal derating. Below 15 V, output regulation degrades and may fall out of the ±2% tolerance band.
Can the LM2677S-12 be synchronized to an external clock, and what are the valid frequency and interface requirements?
Yes, the LM2677S-12 supports external synchronization via its SYNC pin (Pin 5) over 280–400 kHz. The signal must be TTL- or CMOS-compatible (0 V to >3 V), AC-coupled through a 100 pF capacitor with a 1 kΩ pull-down to ground. Synchronization disables current limit foldback, so short-circuit protection remains active but with modified response.
What package options are available for the LM2677S-12, and how do their thermal characteristics differ?
The LM2677S-12 is offered in TO-220 (NDZ0007B) and DDPAK/TO-263 (KTW0007B) packages. The KTW variant achieves θJA = 26°C/W with 7.4× copper area, while NDZ reaches 35°C/W under same conditions. Both include an exposed thermal pad (DAP) that must be soldered to PCB ground for optimal thermal performance.
Does the LM2677S-12 require external feedback resistors to set the 12 V output?
No, the LM2677S-12 has an internally trimmed 12 V feedback divider. Pin 6 (FB) must be connected directly to the output node-no external resistors are needed. This eliminates resistor tolerance errors and simplifies layout, ensuring the specified ±2% output accuracy without calibration.
How does the ON/OFF pin function, and what is the quiescent current in shutdown mode?
The ON/OFF pin (Pin 7) enables or disables the LM2677S-12: pulling it below 0.8 V places the device in standby, reducing input current to 50 μA (typ). An internal 20 μA pull-up holds it high when floating. This low standby current makes LM2677S-12 suitable for battery-backed or energy-harvesting systems requiring ultra-low sleep power.
LM2677S-12 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:
- Obsolete
- 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 FAQ
1.How can I place an order for LM2677S-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677S-12 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 reliable?
The price and inventory of LM2677S-12 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 is usually 5 days.
3.What payment methods are accepted for LM2677S-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677S-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677S-12?
LM2677S-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677S-12 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?
For technical support, including LM2677S-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677S-12 requirements.
6.How does Aetrix verify that LM2677S-12 is sourced from the original manufacturer or authorized distributors?
All LM2677S-12 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 meets industry standards.
7.What is the process for return or replacement of LM2677S-12?
All LM2677S-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2677S-12, 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 part is unused and in its original packaging.
Return procedure for LM2677S-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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