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Texas Instruments LM2677T-3.3
- Part No.:
- LM2677T-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2677T-3.3.pdf
- Description:
- IC REG BUCK 3.3V 5A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:1,935
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Product details
Overview
LM2677T-3.3 from Texas Instruments is a monolithic step-down (buck) DC/DC switching regulator with integrated 100 mΩ DMOS power switch, delivering up to 5 A output current at fixed 3.3 V with ±2% output tolerance over full line and load conditions. It operates from 8 V to 40 V input, achieves up to 92% efficiency, and supports internal 260 kHz or external sync clock (280–400 kHz) for ripple control in communications power supplies.
For engineers reviewing the LM2677T-3.3 datasheet, LM2677T-3.3 pinout, LM2677T-3.3 application, or LM2677T-3.3 equivalent, key selection criteria include input voltage range (8–40 V), 5 A continuous output capability, thermal performance in TO-220 package, standby quiescent current (50 μA), and compatibility with standard off-the-shelf inductors and Schottky catch diodes.
Technical Context
The LM2677T-3.3 implements a current-mode PWM buck controller with internal 260 kHz oscillator or external synchronization capability (280–400 kHz). Its 100 mΩ DMOS switch enables high-efficiency operation across wide input ranges, while built-in thermal shutdown, current limiting, and ON/OFF control support robust system-level power management.
It features a precision feedback amplifier with 1.21 V reference (for adjustable variants) and uses a fixed-output internal resistor divider for 3.3 V regulation. The BOOST capacitor (0.01 μF) ensures full gate drive of the internal MOSFET, minimizing RDS(ON) conduction loss and maintaining >90% efficiency at 5 A load under typical conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±2% over −40°C to +125°C junction temperature, 100 mA–5 A load, and 8–40 V input - ensures stable logic supply for microcontrollers and FPGAs without external feedback resistors. |
| Input Voltage Range | 8 V to 40 V - supports industrial 12/24 V rails, automotive battery-derived inputs, and unregulated DC sources without pre-regulation. |
| Maximum Output Current | 5 A continuous - enables single-chip replacement of linear regulators in high-current embedded systems, reducing heat sink requirements. |
| Switch RDS(ON) | 0.12 Ω typical - limits conduction loss to <1.5 W at 5 A, enabling thermally viable operation in TO-220 package with minimal heatsinking. |
| Efficiency | 82% typical at VIN = 12 V, IOUT = 5 A - delivers >4 W of usable 3.3 V power with <1 W switching/conduction loss, critical for energy-sensitive applications. |
| Standby Quiescent Current | 50 μA when ON/OFF pin ≤0.8 V - allows ultra-low-power system sleep modes without auxiliary LDOs or external disable circuitry. |
| Oscillator Frequency | 260 kHz fixed or 280–400 kHz externally synchronized - enables predictable EMI filtering and consistent ripple frequency placement in RF-sensitive designs. |
Pinout & Package
LM2677T-3.3 is supplied in the TO-220-7 package (package code NDZ0007B), featuring a vertical mount configuration with exposed tab for thermal conduction to heatsink or PCB copper area. Thermal resistance is 65°C/W (no heatsink) or 45°C/W (4 in² copper), enabling reliable 5 A operation with appropriate thermal design.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 2) | Input voltage supply | Accepts 8–40 V unregulated DC; requires local 0.1–0.47 μF ceramic + bulk electrolytic bypassing to suppress high-frequency ringing. |
| VSW (Pin 1 & 4) | Switch node | Drives external inductor; swings from VIN to ~−0.5 V during OFF cycle - must be routed with short, low-inductance traces to minimize EMI and voltage spikes. |
| BOOST (Pin 3) | Bootstrap gate drive | Connects via 0.01 μF/50 V ceramic capacitor to VSW - ensures full enhancement of internal DMOS switch, sustaining low RDS(ON). |
| GND (Pin 5) | Power and signal ground | Common return for all internal circuits and external components; requires low-impedance ground plane to prevent noise coupling into feedback path. |
| SYNC (Pin 5 - shared with GND in NDZ package) | External clock input | Not connected by default; if used, AC-coupled via 100 pF + 1 kΩ to ground - overrides internal oscillator for precise ripple frequency control. |
| FB (Pin 6) | Feedback input | Internally tied to 3.3 V divider - no external resistors needed; sensitive to noise; must avoid inductor flux coupling and routing near noisy nodes. |
| ON/OFF (Pin 7) | Enable/disable control | Logic-level input: <0.8 V disables regulator (50 μA IQ); >2.0 V enables; internal 20 μA pull-up allows open-circuit enable. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100 mΩ DMOS power switch | Eliminates need for external MOSFET and driver, reducing BOM count and layout complexity while maintaining 5 A capability in TO-220 footprint. |
| ±2% output voltage tolerance over full operating range | Guarantees compliance with 3.3 V I/O standards (e.g., PCIe, USB, ARM cores) without post-regulation or trimming, simplifying qualification. |
| External synchronization (280–400 kHz) | Enables deterministic EMI spectrum positioning and coordinated switching in multi-rail systems, avoiding beat frequencies in communication equipment. |
| Thermal shutdown and current limiting | Provides self-protection during overload or ambient temperature excursions, eliminating need for external fault monitoring in industrial deployments. |
| 50 μA standby current with ON/OFF control | Supports low-power wake-on-event architectures in battery-backed or energy-harvesting systems without sacrificing fast turn-on response. |
Applications
| Industrial PLC Power Supply | Automotive Infotainment Pre-regulator |
|---|---|
|
Use Scenario: Provides clean 3.3 V rail for ARM-based controllers and CAN transceivers in programmable logic controllers operating from 24 V DC bus. IC Role / Device Role / Timing Role: Primary step-down regulator delivering regulated 3.3 V at up to 5 A, replacing discrete buck controllers and reducing thermal stress on board. Use Value: High efficiency (>82% at 12 VIN/5 A) minimizes heat generation in sealed enclosures; ±2% tolerance ensures reliable interface with 3.3 V digital peripherals. |
Use Scenario: Generates stable 3.3 V supply for display processors and audio codecs in automotive head units powered from 12 V battery with wide cold-crank transients. IC Role / Device Role / Timing Role: Robust pre-regulator handling 8–40 V input range, including load-dump events, feeding downstream LDOs or point-of-load converters. Use Value: Wide input range and thermal shutdown allow direct connection to vehicle battery without external protection; 50 μA standby enables always-on functionality. |
| Communications Baseband Power | Test Equipment Digital Subsystem |
|
Use Scenario: Powers FPGA configuration memory and ADC/DAC interfaces in LTE baseband units requiring low-noise, tightly regulated 3.3 V. IC Role / Device Role / Timing Role: Synchronized buck regulator operating at 350 kHz to position switching noise away from sensitive IF bands and simplify EMI filter design. Use Value: External SYNC capability enables fixed ripple frequency for repeatable conducted emissions testing; 260 kHz internal option reduces component size for space-constrained modules. |
Use Scenario: Supplies 3.3 V to microcontroller, USB PHY, and data acquisition logic in portable benchtop test instruments with battery and AC adapter inputs. IC Role / Device Role / Timing Role: Main DC/DC converter supporting dual-input operation (12 V adapter or 18 V Li-ion pack), with ON/OFF control for user-initiated power-down. Use Value: 5 A rating accommodates peak current demands of USB enumeration and analog front-end sampling; TO-220 package allows field-serviceable heatsink replacement. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678-3.3 | Higher 8 A current rating, 37 mΩ RDS(ON), same 8–40 V input and 3.3 V fixed output - larger die and higher thermal mass. | Required where sustained >5 A loads or lower dropout at high ambient temperatures exist; not drop-in due to different thermal pad layout and higher quiescent current (10 mA). | Select LM2678-3.3 only when 5 A margin is insufficient or thermal derating below 125°C is critical; verify PCB copper area and heatsink compatibility. |
| TPS54531 | 3.5 A max output, 4.5–28 V input, adjustable or 3.3 V fixed, 570 kHz switching - smaller SOIC-8 package, no BOOST pin, integrated compensation. | Better suited for compact, cost-sensitive designs with <4 A loads; lacks external SYNC and has narrower input range - unsuitable for 36 V industrial or automotive use. | Choose TPS54531 for space-constrained consumer electronics; avoid for 40 V input or 5 A continuous applications where LM2677T-3.3's ruggedness and current capability are essential. |
Compared with LM2678-3.3 and TPS54531, the LM2677T-3.3 uniquely balances 5 A capability, 40 V input tolerance, external SYNC control, and TO-220 serviceability - making it optimal for industrial and transportation systems where reliability, thermal headroom, and EMI predictability are prioritized over miniaturization.
Availability
LM2677T-3.3 is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, and communications baseband power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2677T-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 ICs, with decades of expertise in high-reliability power conversion solutions.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease of use in non-isolated DC/DC buck applications, emphasizing minimal external components, proven inductor compatibility, and robust operation across harsh environments.
FAQ
What is the maximum input voltage rating for LM2677T-3.3?
The absolute maximum input voltage for LM2677T-3.3 is 45 V, but the recommended operating range is 8 V to 40 V per the datasheet. Exceeding 40 V may trigger internal protection or reduce reliability; operation at 40 V is validated for full temperature and load range with proper thermal design.
Does LM2677T-3.3 require an external feedback resistor network?
No, LM2677T-3.3 does not require external feedback resistors. It integrates a precision voltage divider for the fixed 3.3 V output, connecting the FB pin directly to the output. Only the adjustable version (LM2677-ADJ) requires external resistors to set VOUT.
Can LM2677T-3.3 synchronize to an external clock, and what is the valid frequency range?
Yes, LM2677T-3.3 supports external synchronization via the SYNC pin (Pin 5), accepting TTL/CMOS-compatible clocks from 280 kHz to 400 kHz. The external clock must exceed the internal oscillator's upper limit (280 kHz) to avoid erratic reset behavior; a 100 pF capacitor and 1 kΩ pull-down resistor are required for AC coupling.
What thermal performance can be expected from LM2677T-3.3 in its TO-220 package?
In the TO-220-7 (NDZ) package, LM2677T-3.3 has a junction-to-ambient thermal resistance of 65°C/W with minimal copper and 45°C/W with 4 in² of 1 oz. copper. At 5 A and 12 VIN, typical power dissipation is ~1.2 W, resulting in ~54°C rise above ambient with adequate copper - well within the −40°C to +125°C junction limit.
Is LM2677T-3.3 pin-compatible with other members of the LM2677 family?
Yes, all LM2677 variants (3.3 V, 5 V, 12 V, ADJ) share identical pinout and package options (TO-220, DDPAK, VSON). Swapping LM2677T-3.3 for LM2677T-5.0 requires only output capacitor and catch diode re-evaluation - no PCB layout change is needed, though feedback and BOOST networks remain unchanged.
LM2677T-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-7 Formed Leads
- 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):
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2677T-3.3 FAQ
1.How can I place an order for LM2677T-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677T-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 LM2677T-3.3 reliable?
The price and inventory of LM2677T-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 LM2677T-3.3 is usually 5 days.
3.What payment methods are accepted for LM2677T-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2677T-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2677T-3.3?
LM2677T-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677T-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 LM2677T-3.3?
For technical support, including LM2677T-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677T-3.3 requirements.
6.How does Aetrix verify that LM2677T-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2677T-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 LM2677T-3.3 meets industry standards.
7.What is the process for return or replacement of LM2677T-3.3?
All LM2677T-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2677T-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 LM2677T-3.3 part is unused and in its original packaging.
Return procedure for LM2677T-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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