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Texas Instruments LM2677SX-5.0
- Part No.:
- LM2677SX-5.0
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2677SX-5.0.pdf
- Description:
- IC REG BUCK 5V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:2,040
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Product details
Overview
LM2677SX-5.0 from Texas Instruments is a monolithic step-down (buck) DC/DC switching regulator delivering 5V at up to 5A output current, featuring an integrated 100 mΩ DMOS power switch, 260 kHz fixed-frequency internal oscillator, and ±2% output voltage tolerance over full line/load/temperature range. It operates from 8V to 40V input and supports external clock synchronization from 280 kHz to 400 kHz for EMI-sensitive communications equipment.
For engineers reviewing the LM2677SX-5.0 datasheet, LM2677SX-5.0 pinout, LM2677SX-5.0 application, or LM2677SX-5.0 equivalent, key selection criteria include its wide input voltage range, thermal shutdown protection, ON/OFF control with 50 μA standby current, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors in high-efficiency industrial power supplies.
Technical Context
The LM2677SX-5.0 implements a current-mode PWM buck controller with internal ramp compensation and cycle-by-cycle current limiting. Its 100 mΩ DMOS switch enables >90% efficiency at 5A load with 12V input, while the fixed 260 kHz oscillator ensures predictable ripple frequency and simplified filter design.
It integrates feedback error amplification, thermal shutdown, and an ON/OFF logic interface with 0.8V–2.0V threshold. The BOOST capacitor (0.01 µF) provides gate overdrive for low RDS(on), and SYNC functionality allows precise external frequency alignment-critical for multi-rail systems requiring synchronized switching to avoid beat frequencies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±2% (ensures stable rail for microcontrollers and analog circuitry without external resistive divider) |
| Max Output Current | 5 A continuous (supports high-power FPGA I/O banks or motor driver pre-regulation) |
| Input Voltage Range | 8 V to 40 V (enables direct use with 12 V/24 V industrial buses and automotive battery-supplied systems) |
| Switching Frequency | 260 kHz fixed internal oscillator (balances efficiency, inductor size, and EMI performance) |
| Efficiency | 84% typical at 12 VIN, 5 A (reduces thermal load vs. linear regulators; enables compact heatsink-free designs) |
| Standby Current | 50 μA when ON/OFF pin ≤0.8 V (enables ultra-low-power sleep modes in battery-backed instrumentation) |
| Thermal Shutdown | Active at TJ ≥150°C (protects against sustained overload or poor PCB thermal layout) |
Pinout & Package
LM2677SX-5.0 is packaged in the TO-263 (DDPAK) 7-lead surface-mount package with exposed die attach pad (DAP) for enhanced thermal dissipation. Thermal resistance θJA ranges from 26°C/W (with 7.4× DAP copper area) to 56°C/W (minimal copper), enabling reliable 5A operation under industrial ambient conditions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 2) | Input supply connection | Accepts 8–40 V unregulated input; requires local 0.1–0.47 µF ceramic + bulk capacitor for transient suppression |
| VSW (Pin 1) | Internal switch drain node | Connects to inductor and catch diode anode; swings from VIN to ~−0.5 V during OFF-time; drives external Schottky diode |
| BOOST (Pin 3) | Bootstrap gate drive capacitor terminal | Requires 0.01 µF/50 V ceramic capacitor to VSW to enable full enhancement of internal MOSFET (minimizes conduction loss) |
| GND (Pin 4) | Power and signal reference | Must connect to low-impedance ground plane; shared return for switch, feedback, and ON/OFF circuits |
| SYNC (Pin 5) | External clock synchronization input | Accepts TTL/CMOS clock (280–400 kHz); AC-coupled via 100 pF + 1 kΩ to ground; disables current-limit foldback when active |
| FB (Pin 6) | Feedback sense input | Internally connected to 5 V divider; direct connection to output required-no external resistors needed for fixed-output version |
| ON/OFF (Pin 7) | Enable/disable control | Logic-low (≤0.8 V) disables regulator; pulls to ~1.4 V internally; sinks <45 μA in ON state; enables system-level power sequencing |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100 mΩ DMOS switch | Eliminates need for external high-side FET and gate driver; reduces BOM count and layout complexity in 5 A buck designs |
| ±2% output tolerance over −40°C to +125°C | Guarantees compliance with tight analog supply requirements (e.g., ADC references, op-amp rails) without post-regulation |
| External SYNC capability (280–400 kHz) | Enables deterministic ripple frequency placement-essential for meeting CISPR-22 conducted EMI limits in radio transceivers |
| 50 μA standby quiescent current | Supports always-on subsystems (e.g., real-time clocks, CAN wake-up receivers) without compromising battery life |
| Thermal shutdown + current limiting | Provides autonomous fault recovery in overload or short-circuit events; prevents catastrophic failure during prototyping or field operation |
Applications
| Industrial Power Pre-regulator | Communications Equipment Supply |
|---|---|
|
Use Scenario: Converting 24 V factory bus to stable 5 V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary step-down regulator providing isolated, regulated 5 V rail with high PSRR and low output impedance. Use Value: Delivers 5 A continuously at >84% efficiency, reducing heat sink size and enabling conformal-coated PCB designs for harsh environments. |
Use Scenario: Generating clean 5 V for RF front-end ICs and baseband processors in cellular repeaters. IC Role / Device Role / Timing Role: Synchronized buck converter operating at 350 kHz to avoid interference with LTE uplink bands. Use Value: External SYNC input allows precise ripple frequency positioning outside sensitive receive bands, improving SNR by >3 dB. |
| Battery Charger Auxiliary Supply | Test & Measurement Instrumentation |
|
Use Scenario: Providing 5 V bias for charging controllers and status LEDs in 12–36 V Li-ion battery chargers. IC Role / Device Role / Timing Role: High-input-voltage buck regulator with ON/OFF control linked to charger enable signal. Use Value: 50 μA standby current extends battery runtime during idle periods; wide VIN accommodates variable battery pack voltages. |
Use Scenario: Powering precision DACs, ADCs, and reference buffers in portable multimeters and oscilloscope front-ends. IC Role / Device Role / Timing Role: Low-noise, tightly regulated 5 V source with minimal load regulation drift (<0.1%) across temperature. Use Value: ±2% output tolerance and <13 mΩ COUT ESR support sub-mV output ripple-critical for 16-bit measurement accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678-5.0 | Higher 6.5 A current limit; identical pinout and features but rated for higher peak loads | Better suited for transient-heavy applications like servo drivers where 5 A average + surge margin is required | Select LM2678-5.0 only if design requires >5 A continuous or >6 A pulsed output; otherwise LM2677SX-5.0 offers optimal cost/performance balance |
| TPS54560B | Wider 3.5–60 V input range; 500 kHz adjustable frequency; smaller 8-pin SOIC package | Preferred for space-constrained designs needing higher switching frequency and lower EMI filtering component count | Choose TPS54560B when board area is critical or input may dip below 8 V; LM2677SX-5.0 remains superior for 8–40 V industrial reliability and thermal robustness |
Compared with LM2678-5.0 and TPS54560B, the LM2677SX-5.0 delivers best-in-class thermal performance in TO-263 packaging, maintains strict ±2% regulation without trimming, and simplifies design with fixed-frequency operation-making it ideal for cost-sensitive, thermally demanding industrial power stages where long-term stability outweighs ultra-high frequency or extended VIN range needs.
Availability
LM2677SX-5.0 is available at Aetrix Electronics and suitable for industrial automation, communications infrastructure, and test equipment requiring stable component supply, long-lifecycle availability, and consistent electrical performance across production batches.
Supply support for LM2677SX-5.0 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 engineers seeking fast, robust, and minimal-component buck regulator solutions for industrial, telecom, and battery-powered systems.
FAQ
What is the maximum input voltage rating for the LM2677SX-5.0?
The absolute maximum input voltage for the LM2677SX-5.0 is 45 V, but the recommended operating range is 8 V to 40 V per the datasheet. Exceeding 40 V risks violating the specified operating conditions and may trigger overvoltage stress on internal circuitry-even if within absolute maximum ratings. For reliable long-term operation, maintain VIN ≤40 V in all use cases of the LM2677SX-5.0.
Does the LM2677SX-5.0 require external feedback resistors?
No, the LM2677SX-5.0 does not require external feedback resistors. As a fixed-output variant, it contains internal resistor dividers calibrated for 5.0 V output. Pin 6 (FB) must be connected directly to the output node-no external components are needed. This simplifies layout and eliminates resistor tolerance errors that could affect regulation accuracy in the LM2677SX-5.0.
Can the LM2677SX-5.0 synchronize to an external clock, and what are the timing constraints?
Yes, the LM2677SX-5.0 supports external synchronization via Pin 5 (SYNC) across 280 kHz to 400 kHz. The external clock must be TTL/CMOS-compatible (0–>3 V), AC-coupled using a 100 pF capacitor and 1 kΩ pull-down resistor. Critical constraint: the external frequency must exceed the internal oscillator's upper limit (280 kHz) to prevent erroneous reset of the PWM ramp generator-ensuring deterministic operation of the LM2677SX-5.0.
What thermal considerations apply to the LM2677SX-5.0 in TO-263 (KTW) package?
The LM2677SX-5.0 in TO-263 package has θJA ranging from 26°C/W (with 7.4× DAP copper area) to 56°C/W (minimal copper). At 5 A load and 12 VIN, power dissipation is ~0.8 W-requiring ≥1.0 in² of 1 oz. copper connected to the DAP for safe operation at 125°C junction temperature. Without adequate copper, thermal shutdown may activate under full load, making proper PCB thermal design essential for the LM2677SX-5.0.
How does the ON/OFF pin function, and what happens to output voltage during disable?
The ON/OFF pin (Pin 7) disables the LM2677SX-5.0 when pulled ≤0.8 V, reducing quiescent current to 50 μA. During disable, the internal switch opens and output voltage decays through the load and output capacitor. No active discharge path is provided-so hold-up time depends on output capacitance and load. For controlled shutdown, pair the LM2677SX-5.0 with an external load switch if rapid output discharge is required.
LM2677SX-5.0 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:
- 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):
- 5V
- 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-5.0 FAQ
1.How can I place an order for LM2677SX-5.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677SX-5.0 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-5.0 reliable?
The price and inventory of LM2677SX-5.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2677SX-5.0 is usually 5 days.
3.What payment methods are accepted for LM2677SX-5.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677SX-5.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677SX-5.0?
LM2677SX-5.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677SX-5.0 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-5.0?
For technical support, including LM2677SX-5.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677SX-5.0 requirements.
6.How does Aetrix verify that LM2677SX-5.0 is sourced from the original manufacturer or authorized distributors?
All LM2677SX-5.0 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-5.0 meets industry standards.
7.What is the process for return or replacement of LM2677SX-5.0?
All LM2677SX-5.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM2677SX-5.0, 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-5.0 part is unused and in its original packaging.
Return procedure for LM2677SX-5.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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