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Texas Instruments LM2677SD-3.3/NOPB
- Part No.:
- LM2677SD-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2677SD-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,816
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Product details
Overview
LM2677SD-3.3/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC voltage regulator with fixed 3.3-V output, 5-A load capability, 8 V to 40 V input range, 260-kHz internal oscillator, and ±2% output voltage tolerance over line/load/temperature. It integrates a 100-mΩ DMOS power switch and supports external clock synchronization for ripple frequency control in communications systems.
For engineers reviewing the LM2677SD-3.3/NOPB datasheet, LM2677SD-3.3/NOPB pinout, LM2677SD-3.3/NOPB application, or LM2677SD-3.3/NOPB equivalent, key selection criteria include input voltage range compatibility, thermal performance in TO-263-7 (KTW) package, standby current under 100 μA, feedback configuration for fixed-output operation, and sync-capable switching frequency control for EMI-sensitive designs.
Technical Context
The LM2677SD-3.3/NOPB implements a current-mode PWM buck controller with integrated high-side DMOS switch, bootstrap gate drive (CB pin), and internal 1.21-V reference. Its 260-kHz fixed-frequency oscillator enables predictable ripple placement, while the SYNC input accepts 280–400 kHz external clocks to override internal timing and align switching noise in multi-rail systems.
Operation relies on continuous conduction mode (CCM) with duty cycle determined by VIN/VOUT ratio, supported by internal thermal shutdown, cycle-by-cycle current limiting (6.1–8.75 A), and ON/OFF logic-level enable. The FB pin connects directly to output for fixed 3.3-V regulation-no external divider required-while GND pins provide low-impedance return paths for high di/dt currents.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±2% over –40°C to 125°C, 8–40 V input, 100 mA–5 A load - ensures stable logic supply for microcontrollers and FPGAs without external feedback resistors. |
| Max Output Current | 5 A continuous - supports high-power digital loads such as SoCs, DSPs, or multi-rail FPGA core supplies. |
| Input Voltage Range | 8 V to 40 V - compatible with 12-V/24-V industrial buses, automotive battery systems (with cold-crank margin), and telecom intermediate rails. |
| Switch RDS(ON) | 0.12 Ω typical at 25°C - minimizes conduction loss and enables >90% efficiency at full load with proper thermal layout. |
| Standby Current | 50 μA max at 25°C when ON/OFF = 0 V - enables ultra-low-power system sleep modes without external LDOs. |
| Oscillator Frequency | 260 kHz fixed (225–280 kHz over temp); sync-capable up to 400 kHz - balances inductor size, EMI, and transient response for industrial and comms applications. |
| Thermal Resistance | RθJA = 26°C/W with 1.0064 in² copper - requires minimal heatsinking in TO-263-7 package for 5-A operation at 40°C ambient. |
Pinout & Package
LM2677SD-3.3/NOPB uses the TO-263-7 (KTW) thermally enhanced surface-mount package (10.16 mm × 8.69 mm), with exposed thermal pad soldered to PCB ground plane for optimal heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW | Switch node output | Drives inductor high-side; swings between VIN and ~–0.5 V during off-time - must be routed short and wide to minimize EMI and ringing. |
| VIN | Main power input | Connects to bulk input capacitor (CIN) and high-frequency bypass - path to GND must be shortest possible to reduce switching loop inductance. |
| CB | Bootstrap capacitor connection | Requires 0.01-μF ceramic cap to VSW; enables full enhancement of internal MOSFET gate - critical for low RDS(ON) and efficiency. |
| GND | Power ground | Multiple pins tied to solid ground plane; carries high di/dt return current - separates analog and power ground only at single-point star connection. |
| SYNC | External clock input | Accepts 280–400 kHz TTL/CMOS signal via 100-pF AC coupling; overrides internal oscillator for synchronized ripple filtering in multi-converter systems. |
| FB | Feedback sense | Internally connected to 3.3-V output divider - direct wire to output capacitor cathode; no external resistors needed for fixed-output operation. |
| ON/OFF | Enable control | Logic-compatible input: <0.8 V = shutdown (50 μA IQ), >1.4 V = active - internal 20-μA pullup allows floating for always-on use. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100-mΩ DMOS switch | Eliminates external MOSFET and driver, reducing BOM count and layout complexity while maintaining 5-A capability with <0.15-V dropout at full load. |
| ±2% output tolerance over full conditions | Guarantees reliable 3.3-V supply for sensitive digital ICs without post-regulation, even at temperature extremes and max load. |
| External sync capability (280–400 kHz) | Enables deterministic ripple frequency positioning for compliance with EMI standards and avoids beat frequencies in multi-rail systems. |
| 50-μA standby quiescent current | Supports battery-backed or energy-harvesting systems requiring sub-100-μA shutdown current without external enable circuitry. |
| Thermal shutdown + current limit protection | Provides autonomous fault recovery under overload or poor heatsinking - no external sensing or latch-up circuitry required. |
Applications
| Industrial PLC Power Supply | Automotive Infotainment Core Rail |
|---|---|
Use Scenario: Provides primary 3.3-V rail for programmable logic controllers operating from 24-V DC bus with wide ambient temperature variation. IC Role / Device Role / Timing Role: Step-down regulator delivering regulated 3.3-V/5-A output with internal 260-kHz switching - eliminates need for external clock source or compensation network. Use Value: Fixed-output configuration reduces component count; ±2% tolerance ensures consistent MCU/FPGA operation across –40°C to 85°C industrial range. | Use Scenario: Powers application processor and memory subsystem in head-unit systems with 12-V battery input and cold-crank down to 6 V. IC Role / Device Role / Timing Role: High-current buck converter with thermal shutdown and ON/OFF control - enables coordinated system sleep/wake via vehicle CAN bus signals. Use Value: 50-μA standby current extends battery life during ignition-off; TO-263 thermal pad handles 5-A load without heatsink in constrained chassis space. |
| Communications Base Station Pre-regulator | Test Equipment Digital Subsystem |
Use Scenario: Generates clean 3.3-V intermediate rail from 48-V backplane in LTE small-cell radios where spectral purity is critical. IC Role / Device Role / Timing Role: Sync-capable buck regulator locked to system master clock - forces switching ripple into known frequency band for predictable filter design. Use Value: External 350-kHz sync eliminates variable-frequency jitter; enables use of smaller LC filters while meeting FCC Class B conducted emissions limits. | Use Scenario: Supplies 3.3-V power to high-speed ADCs, DACs, and FPGA logic in automated test equipment requiring low-noise, fast transient response. IC Role / Device Role / Timing Role: Primary DC-DC converter with 260-kHz fixed frequency - provides stable ripple frequency for analog section filtering and deterministic power sequencing. Use Value: 0.12-Ω RDS(ON) and optimized layout support <10-mV output ripple at 5-A load; current limit protects against shorted DUT connections. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678SD-3.3/NOPB | Same pinout, 65-kHz lower switching frequency (195 kHz), higher RDS(ON) (0.15 Ω), reduced efficiency at light loads | Better suited for cost-sensitive, low-EMI applications where larger inductors are acceptable | Select when lower switching losses and reduced EMI priority outweigh size constraints |
| TPS54560DGRT | Adjustable output (1.21–36 V), 600-kHz switching, 0.072-Ω RDS(ON), requires external feedback resistors | Offers greater flexibility for multi-voltage systems but increases design complexity and BOM count | Choose when programmable output or higher frequency (smaller magnetics) justifies added components and layout effort |
Compared with LM2678SD-3.3/NOPB, LM2677SD-3.3/NOPB delivers higher efficiency at full load due to lower RDS(ON) and faster switching, while TPS54560DGRT trades fixed-output simplicity for adjustable voltage and higher frequency - making LM2677SD-3.3/NOPB optimal for dedicated 3.3-V/5-A industrial rails requiring minimal external parts.
Availability
LM2677SD-3.3/NOPB is available at Aetrix Electronics and suitable for industrial automation, automotive infotainment, communications infrastructure, and test equipment requiring stable component supply with long-term manufacturability.
Supply support for LM2677SD-3.3/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 leadership in high-reliability industrial and automotive solutions.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family of integrated DC-DC regulators, designed specifically for ease of use in high-current, wide-input-voltage applications where minimal external components and robust thermal performance are essential.
FAQ
What is the maximum input voltage rating for LM2677SD-3.3/NOPB?
The absolute maximum input voltage for LM2677SD-3.3/NOPB is 45 V, but the recommended operating range is 8 V to 40 V. Operation above 40 V risks exceeding safe junction temperature or violating SOA limits, especially at high load currents. TI specifies 40 V as the upper limit for guaranteed performance across temperature and load conditions - exceeding this may cause premature failure or degraded efficiency. Always verify thermal design margins when operating near 40 V.
Does LM2677SD-3.3/NOPB require external feedback resistors?
No, LM2677SD-3.3/NOPB does not require external feedback resistors. As a fixed-output variant, it internally connects the FB pin to a precision 1.21-V reference and output divider network calibrated for 3.3 V. The FB pin must be wired directly to the output capacitor's cathode terminal to close the regulation loop. Adding external resistors would disrupt factory-trimmed accuracy and potentially cause overvoltage or instability.
Can LM2677SD-3.3/NOPB synchronize to an external clock?
Yes, LM2677SD-3.3/NOPB supports external clock synchronization via the SYNC pin (Pin 5). It accepts TTL/CMOS-compatible signals from 280 kHz to 400 kHz, ac-coupled through a 100-pF capacitor and 1-kΩ resistor to ground. When enabled, the internal 260-kHz oscillator is disabled, and switching frequency locks precisely to the external clock - enabling deterministic ripple placement for EMI filtering and multi-converter phase alignment.
What thermal considerations apply to LM2677SD-3.3/NOPB in TO-263-7 package?
LM2677SD-3.3/NOPB in TO-263-7 (KTW) package achieves RθJA = 26°C/W with 1.0064 in² of 1-oz copper - requiring full-soldering of the exposed thermal pad to a solid ground plane. Without adequate copper area, junction temperature rise exceeds safe limits at 5-A load. TI recommends minimum 10×10 mm thermal pad with ≥4 thermal vias to inner ground layers. Ambient temperature must stay ≤60°C for continuous 5-A operation with 26°C/W thermal resistance.
How does the ON/OFF pin function on LM2677SD-3.3/NOPB?
The ON/OFF pin (Pin 7) controls LM2677SD-3.3/NOPB's enable state: voltage <0.8 V places the device in shutdown mode with 50 μA standby current, while >1.4 V activates regulation. An internal 20-μA pullup allows the pin to float for default-on operation. Driving the pin externally requires logic-level signals within 0–6 V absolute limits; exceeding 6 V risks damage. This pin enables system-level power sequencing and low-power sleep states without external MOSFET switches.
LM2677SD-3.3/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- 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):
- 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)
LM2677SD-3.3/NOPB FAQ
1.How can I place an order for LM2677SD-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677SD-3.3/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 LM2677SD-3.3/NOPB reliable?
The price and inventory of LM2677SD-3.3/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2677SD-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM2677SD-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677SD-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677SD-3.3/NOPB?
LM2677SD-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677SD-3.3/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 LM2677SD-3.3/NOPB?
For technical support, including LM2677SD-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677SD-3.3/NOPB requirements.
6.How does Aetrix verify that LM2677SD-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2677SD-3.3/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 LM2677SD-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM2677SD-3.3/NOPB?
All LM2677SD-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2677SD-3.3/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 LM2677SD-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM2677SD-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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