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Texas Instruments LM2677SDX-3.3
- Part No.:
- LM2677SDX-3.3
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2677SDX-3.3.pdf
- Description:
- IC REG BUCK 3.3V 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,472
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Product details
Overview
LM2677SDX-3.3 from Texas Instruments is a monolithic step-down (buck) DC/DC voltage regulator IC with fixed 3.3V output, 5A load capability, 8V–40V input range, and integrated 100 mΩ DMOS power switch. It delivers up to 92% efficiency in optimized designs and supports external clock synchronization from 280 kHz to 400 kHz for precise ripple frequency control in noise-sensitive applications such as communications equipment.
For engineers reviewing the LM2677SDX-3.3 datasheet, LM2677SDX-3.3 pinout, LM2677SDX-3.3 application, or LM2677SDX-3.3 equivalent, key selection criteria include its ±2% output tolerance over full line/load/temperature, 50 μA standby current, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.
Technical Context
The LM2677SDX-3.3 implements a fixed-frequency PWM buck controller with internal 260 kHz oscillator (±15% variation), duty cycle range of 0–91%, and current-mode control architecture enabling fast transient response and stable operation across wide input/output conditions. Its integrated DMOS switch eliminates external high-side FET requirements while supporting continuous conduction mode (CCM) operation at full 5A load.
It features dedicated BOOST, SYNC, ON/OFF, and FB pins enabling active gate drive boosting, external frequency synchronization, logic-level enable/disable control, and precision feedback regulation - all without requiring external compensation components in standard configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±2% over −40°C to +125°C, 100 mA–5 A load, 8–40 V input - ensures stable logic supply for microcontrollers and FPGAs. |
| Input Voltage Range | 8 V to 40 V - supports industrial 12/24 V rails and automotive battery-derived supplies with transient tolerance. |
| Max Output Current | 5 A continuous - enables single-regulator power delivery for mid-power digital subsystems without parallel stages. |
| Switch RDS(ON) | 100 mΩ typical - minimizes conduction loss and thermal rise under full load, reducing heatsink requirements. |
| Efficiency | Up to 92% at 12 VIN/5 A (12 V version); 82% at 12 VIN/5 A (3.3 V version) - balances conversion loss vs. thermal design constraints. |
| Standby Current | 50 μA when ON/OFF pin < 0.8 V - enables ultra-low-power system sleep modes without auxiliary LDOs. |
| Oscillator Frequency | 260 kHz fixed (225–280 kHz range) or externally synchronized 280–400 kHz - allows EMI filtering optimization and multi-rail frequency interleaving. |
Pinout & Package
The LM2677SDX-3.3 is packaged in the 7-lead DDPAK/TO-263 (package code KTW0007B), featuring exposed thermal pad (DAP) for enhanced PCB heat dissipation. Thermal resistance θJA ranges from 26°C/W (with 7.4× pad copper area) to 56°C/W (minimal copper), enabling scalable thermal design.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 2) | Input Power Supply | Accepts 8–40 V unregulated input; requires local 0.1–0.47 μF ceramic + bulk capacitor for high di/dt stability. |
| VSW (Pin 1) | Switch Node | Drives external catch diode and inductor; swings between VIN and ~−0.5 V during OFF-time; critical for layout EMI control. |
| CBOOST (Pin 3) | Bootstrap Capacitor Terminal | Connects to VSW via 0.01 μF/50 V ceramic capacitor to generate >VIN gate drive for internal MOSFET. |
| GND (Pin 4) | Power Ground Reference | Common return for internal circuitry, switch, and feedback amplifier; must connect to low-inductance ground plane. |
| SYNC (Pin 5) | External Clock Input | AC-coupled TTL/CMOS clock (280–400 kHz) resets internal oscillator; disables current-limit foldback when active. |
| FB (Pin 6) | Feedback Input | Direct connection to 3.3 V output sets regulation point; internal resistive divider eliminates external resistor network. |
| ON/OFF (Pin 7) | Enable/Disable Control | Logic-low (< 0.8 V) disables regulator and reduces quiescent current to 50 μA; internal 20 μA pull-up. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100 mΩ DMOS Switch | Eliminates need for external high-side MOSFET and associated gate driver, reducing BOM count and layout complexity. |
| ±2% Output Tolerance | Guaranteed across full temperature, line, and load range - meets tight supply requirements for 3.3 V I/O and core logic. |
| External Sync Capability | Enables deterministic switching frequency alignment across multiple rails to avoid beat frequencies and simplify EMI filter design. |
| Thermal Shutdown & Current Limit | Protects against sustained overload or ambient overheating; current limit threshold is 5.75–8.75 A (typical 6.1 A). |
| Simple External Component Set | Requires only one inductor, one catch diode, two capacitors (input/output), and one boost capacitor - no compensation network needed. |
Applications
| Industrial PLC Power Supply | Automotive Infotainment Pre-regulator |
|---|---|
|
Use Scenario: Provides clean 3.3 V rail for ARM Cortex-M7 MCU, CAN transceivers, and display interface in programmable logic controllers operating from 24 V DC field bus. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 3.3 V at up to 5 A with thermal robustness across −40°C to +85°C ambient. Use Value: Replaces discrete buck controller + external MOSFET solution, reducing footprint by 35% and eliminating gate-drive timing validation. |
Use Scenario: Generates stable 3.3 V supply for audio DSP, touch controller, and USB PHY in head-unit systems powered from 12 V battery with load-dump transients. IC Role / Device Role / Timing Role: High-efficiency pre-regulator stepping down 12–28 V automotive input to 3.3 V before low-noise LDO post-regulation. Use Value: Delivers 82% efficiency at 12 VIN/5 A, minimizing heat buildup in confined dash-mount enclosures without forced airflow. |
| Communications Baseband Module | Test Equipment Digital Subsystem |
|
Use Scenario: Powers FPGA configuration memory, ADC reference buffers, and RF front-end biasing in LTE small-cell baseband boards. IC Role / Device Role / Timing Role: Synchronized buck converter locked to system master clock (300 kHz) to position switching noise outside sensitive IF bands. Use Value: External SYNC pin enables precise ripple frequency placement, reducing conducted EMI filtering component count by 2–3 per rail. |
Use Scenario: Supplies 3.3 V to high-speed logic analyzers, protocol testers, and FPGA-based signal generators requiring low-noise, fast-transient response. IC Role / Device Role / Timing Role: Main DC/DC stage delivering 5 A peak current during burst-mode data acquisition with <100 mV load-step deviation. Use Value: Current-mode control and 260 kHz switching yield <50 μs recovery time from 1 A to 5 A load steps, preserving measurement 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 |
|---|---|---|---|
| LM2678SDX-3.3 | Same pinout, 65 V max input, lower efficiency (80% @12V/5A), higher RDS(ON) (120 mΩ) | Better suited for 48 V telecom inputs; less optimal for 12–24 V industrial use due to higher conduction loss. | Select when input may exceed 40 V; verify thermal margin with higher RDS(ON). |
| TPS54560DGQR | 60 V input, 5 A, adjustable output, 100 kHz–2.5 MHz sync range, smaller 10-pin MSOP package | Requires external feedback resistors; supports wider frequency tuning but adds design complexity for fixed 3.3 V use. | Choose for space-constrained layouts or when programmable output or >400 kHz sync is required. |
Compared with LM2677SDX-3.3, LM2678SDX-3.3 trades efficiency for higher input voltage rating, while TPS54560DGQR offers greater frequency flexibility and smaller footprint at the cost of added external components and reduced out-of-box simplicity.
Availability
LM2677SDX-3.3 is available at Aetrix Electronics and suitable for industrial automation, automotive infotainment, and communications infrastructure requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2677SDX-3.3 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 ease-of-use in non-isolated DC/DC buck applications where minimal external components, predictable performance, and robust protection are prioritized over ultra-high density or ultra-wide frequency range.
FAQ
What is the maximum input voltage rating for LM2677SDX-3.3?
The absolute maximum input voltage for LM2677SDX-3.3 is 45 V, but the recommended operating range is 8 V to 40 V. Exceeding 40 V risks violating the specified operating conditions and may trigger overvoltage stress on internal circuitry, especially the BOOST capacitor and switch node. Always observe derating guidelines in TI's SNVS077I datasheet for reliability-critical designs.
Does LM2677SDX-3.3 require an external feedback resistor network?
No, LM2677SDX-3.3 does not require external feedback resistors. It integrates precision internal resistive dividers calibrated for 3.3 V output, so the FB pin connects directly to the output rail. This simplifies layout, eliminates resistor tolerance errors, and ensures guaranteed ±2% regulation without trimming - a key advantage over adjustable regulators like LM2677-ADJ.
Can LM2677SDX-3.3 be synchronized to an external clock source?
Yes, LM2677SDX-3.3 supports external synchronization via the SYNC pin (Pin 5). When driven with a TTL/CMOS-compatible clock signal (280–400 kHz), it locks its switching frequency to the external source. This enables consistent EMI filtering and avoids beat frequencies in multi-rail systems - but note that current-limit foldback is disabled during sync operation.
What thermal considerations apply to LM2677SDX-3.3 in the DDPAK/TO-263 package?
LM2677SDX-3.3 in the KTW0007B (DDPAK/TO-263) package achieves θJA = 26°C/W with 7.4× die-pad copper area and thermal vias. For 5 A continuous operation at 12 VIN, junction temperature rise is ~130°C above ambient - requiring careful PCB copper design and possibly forced air. TI recommends connecting the DAP pad directly to a solid ground plane using ≥6 thermal vias.
Is LM2677SDX-3.3 RoHS compliant and lead-free?
Yes, LM2677SDX-3.3 is RoHS compliant and lead-free per TI's packaging standards. The DDPAK/TO-263 package uses matte tin (Sn) lead finish and meets JEDEC J-STD-020 moisture sensitivity level (MSL) 3. Full compliance documentation, including material declarations and test reports, is available through TI's product folder and authorized distributors.
LM2677SDX-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- 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):
- 3.3V
- 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:
- 14-VSON (5x6)
LM2677SDX-3.3 FAQ
1.How can I place an order for LM2677SDX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677SDX-3.3 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 LM2677SDX-3.3 reliable?
The price and inventory of LM2677SDX-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2677SDX-3.3 is usually 5 days.
3.What payment methods are accepted for LM2677SDX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677SDX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677SDX-3.3?
LM2677SDX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677SDX-3.3 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 LM2677SDX-3.3?
For technical support, including LM2677SDX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677SDX-3.3 requirements.
6.How does Aetrix verify that LM2677SDX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2677SDX-3.3 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 LM2677SDX-3.3 meets industry standards.
7.What is the process for return or replacement of LM2677SDX-3.3?
All LM2677SDX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2677SDX-3.3, 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 LM2677SDX-3.3 part is unused and in its original packaging.
Return procedure for LM2677SDX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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