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Texas Instruments LM2677SD-ADJ
- Part No.:
- LM2677SD-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2677SD-ADJ.pdf
- Description:
- IC REG BUCK ADJ 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,222
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Product details
Overview
LM2677SD-ADJ from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator IC with integrated 100-mΩ DMOS power switch, delivering up to 5 A output current, adjustable output voltage from 1.2 V to 37 V, and operating from 8 V to 40 V input. It serves as a high-efficiency (>90%) primary power conversion stage in industrial power supplies and battery-powered systems.
For engineers reviewing the LM2677SD-ADJ datasheet, LM2677SD-ADJ pinout, LM2677SD-ADJ application, or LM2677SD-ADJ equivalent, key selection criteria include its 260-kHz fixed-frequency oscillator, ±2% output voltage tolerance over line/load/temperature, 50-μA standby quiescent current in shutdown mode, external sync capability (280–400 kHz), and thermal shutdown/current-limit protection.
Technical Context
The LM2677SD-ADJ implements a voltage-mode PWM control architecture with an internal 260-kHz oscillator and a two-stage feedback amplifier referenced to a 1.21-V precision bandgap. Its bootstrap-driven high-side DMOS switch enables efficient buck conversion without requiring external gate drivers.
It supports both self-oscillating operation and external synchronization via the SYNC pin, where an externally applied TTL/CMOS clock overrides the internal oscillator and fixes ripple frequency-critical for EMI-sensitive communications equipment. The FB pin senses output voltage through an external resistor divider, enabling precise programmable regulation across the full 1.2 V–37 V range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5 A maximum continuous load current - supports high-power downstream rails without external current boosting. |
| Input Voltage Range | 8 V to 40 V - compatible with 12 V/24 V industrial buses and wide-range battery inputs (e.g., 3S–10S Li-ion). |
| Output Voltage Range | 1.2 V to 37 V (adjustable) - set via external resistor divider on FB pin; enables single-part flexibility across multiple system voltages. |
| Feedback Reference | 1.21 V ±1.2% - high-accuracy internal reference ensures ±2% total output tolerance over temperature and load. |
| Switch RDS(on) | 0.14 Ω typical at 25°C - low conduction loss enables >90% efficiency at 5-A load with proper layout and component selection. |
| Oscillator Frequency | 260 kHz fixed (internal) or 280–400 kHz (external sync) - determines inductor size, ripple frequency, and EMI filter design point. |
| Standby Current | 50 μA max at TJ = 25°C - enables ultra-low-power shutdown for battery longevity in portable applications. |
| Thermal Protection | Integrated thermal shutdown - disables switching above ~160°C junction temperature to prevent damage during overload or poor heatsinking. |
Pinout & Package
LM2677SD-ADJ is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad (DAP), measuring 10.16 mm × 8.69 mm. The DAP must be soldered to a PCB ground plane for optimal thermal performance and electrical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW | Switch node output | Drives external inductor; swings between VIN and ~−0.5 V (Schottky drop); requires low-inductance routing to minimize EMI and ringing. |
| VIN | Power input | Supplies internal circuitry and high-side switch; must be decoupled with low-ESR capacitor placed near pin with short ground path. |
| CB | Bootstrap capacitor connection | Connects 0.01 μF ceramic capacitor to VSW; provides gate drive voltage >VIN to fully enhance internal DMOS switch. |
| GND | Power ground | Common return for input/output capacitors, feedback network, and thermal pad; requires solid copper pour for low impedance. |
| SYNC | External clock input | Accepts 280–400 kHz TTL/CMOS signal (AC-coupled via 100 pF + 1 kΩ to GND); overrides internal oscillator for synchronized ripple control. |
| FB | Feedback sense input | High-impedance input (85 nA bias) referenced to 1.21 V; connects to resistor divider to set output voltage precisely. |
| ON/OFF | Enable control input | Logic-level enable: >1.4 V = active, <0.8 V = shutdown; internal 20-μA pullup allows floating for default ON operation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 100-mΩ DMOS switch | Eliminates need for external MOSFET and driver, reducing BOM count and layout complexity while maintaining 5-A capability. |
| ±2% output voltage tolerance | Guaranteed over full line (8–40 V), load (100 mA–5 A), and temperature (−40°C to +125°C) - reduces need for post-regulation trimming. |
| External sync input (280–400 kHz) | Enables deterministic ripple frequency placement for consistent EMI filtering and coexistence with RF subsystems in comms gear. |
| 50-μA shutdown quiescent current | Supports energy-sensitive applications such as remote sensors or backup power systems where standby leakage must be minimized. |
| Thermal shutdown & current limit | Protects against sustained overloads and inadequate heatsinking without external monitoring circuitry - improves system reliability. |
| SIMPLE SWITCHER® design support | Compatible with pre-characterized inductors from Renco, Pulse, and Coilcraft - accelerates design validation and reduces iteration cycles. |
Applications
| Industrial Power Supply | Battery-Powered Equipment |
|---|---|
Use Scenario: Primary 24-V-to-5-V conversion in programmable logic controller (PLC) backplane power distribution. IC Role / Device Role / Timing Role: Step-down regulator providing stable 5-V rail for microcontroller, I/O drivers, and communication interfaces. Use Value: High efficiency (>90% at 5 A) minimizes heat buildup in enclosed enclosures; wide 8–40 V input accommodates brownout and surge conditions. | Use Scenario: Main DC-DC stage in portable test instrument powered by 3S Li-ion battery (9–12.6 V). IC Role / Device Role / Timing Role: Adjustable buck converter configured for 3.3-V system rail with dynamic voltage scaling capability. Use Value: 50-μA shutdown current extends battery life during sleep mode; ±2% output tolerance ensures reliable MCU operation across battery discharge curve. |
| Communications Equipment | Automotive Aftermarket Systems |
Use Scenario: Synchronized power supply for RF transceiver module requiring clean, predictable switching noise spectrum. IC Role / Device Role / Timing Role: Buck regulator locked to system master clock via SYNC pin to fix ripple at 350 kHz for harmonic alignment. Use Value: External sync eliminates beat frequencies and simplifies EMI filter design; thermal shutdown prevents failure during high ambient temperature operation. | Use Scenario: 12-V-to-5-V conversion in vehicle-mounted data logger operating from automotive battery (9–16 V nominal, up to 40 V load dump). IC Role / Device Role / Timing Role: Input-tolerant buck regulator supplying isolated 5-V logic rail with built-in overvoltage and thermal protection. Use Value: 40-V absolute max input rating and integrated protection eliminate need for upstream TVS or discrete OVP circuits. |
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 | Fixed 5-V output; identical pinout, package, and 5-A rating; no FB pin or external divider required. | Eliminates resistor selection and layout for fixed-rail designs; lacks output adjustability. | Select when system requires only 5 V and simplicity outweighs flexibility. |
| LM5164QDDARQ1 | 42-V input, 1-A output, 2.2-MHz switching, integrated high-side FET; AEC-Q100 qualified. | Lower current, higher frequency, automotive-grade; not pin-compatible; requires different magnetics and layout. | Select for automotive applications needing qualification and smaller solution size, accepting reduced output current. |
Compared with LM2678-5.0, the LM2677SD-ADJ trades fixed-output simplicity for full voltage programmability; compared with LM5164QDDARQ1, it offers higher current and proven thermal robustness in industrial environments but lacks automotive qualification and high-frequency operation.
Availability
LM2677SD-ADJ is available at Aetrix Electronics and suitable for industrial automation, battery-powered instrumentation, communications infrastructure, and automotive aftermarket systems requiring stable component supply and long-term manufacturability.
Supply support for LM2677SD-ADJ 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 headquartered in Dallas, Texas, designing and manufacturing analog and embedded processing chips for industrial, automotive, and consumer markets.
The LM2677 series belongs to TI's SIMPLE SWITCHER® family of integrated DC-DC regulators, engineered for ease of use, high efficiency, and minimal external component count in medium-power buck applications.
FAQ
What is the minimum input voltage required for stable operation of the LM2677SD-ADJ?
The LM2677SD-ADJ requires a minimum input voltage of 8 V to maintain regulation and internal circuit functionality. Below this threshold, the device may fail to start or drop out of regulation. This specification is validated across −40°C to +125°C junction temperature and applies regardless of output voltage setting or load condition.
Can the LM2677SD-ADJ be synchronized to an external clock, and what are the valid frequency and interface requirements?
Yes, the LM2677SD-ADJ supports external synchronization via its SYNC pin. Valid input frequencies range from 280 kHz to 400 kHz. The signal must be TTL- or CMOS-compatible (0 V to >3 V), AC-coupled using a 100-pF capacitor and terminated with a 1-kΩ resistor to GND. Operation outside this range may cause erratic switching or loss of regulation.
What is the purpose of the CB pin on the LM2677SD-ADJ, and what capacitor value is recommended?
CB is the bootstrap capacitor terminal for the high-side gate driver. It must be connected to the VSW pin via a 0.01-μF (10-nF) high-quality ceramic capacitor to generate sufficient gate-source voltage for full enhancement of the internal DMOS switch. Using a lower-value or lossy capacitor risks increased RDS(on), reduced efficiency, and thermal stress.
How does the LM2677SD-ADJ achieve ±2% output voltage accuracy, and over what conditions is this guaranteed?
The LM2677SD-ADJ achieves ±2% output voltage accuracy through a precision 1.21-V internal reference and tightly matched internal resistors in the error amplifier. This tolerance is guaranteed over full line (8–40 V), load (100 mA–5 A), and temperature (−40°C to +125°C) ranges - confirmed by TI's production testing and statistical correlation methods per datasheet Section 6.8.
Does the LM2677SD-ADJ include protection features, and how do they behave under fault conditions?
Yes, the LM2677SD-ADJ integrates thermal shutdown, cycle-by-cycle current limiting, and undervoltage lockout. During overtemperature, it latches off until junction temperature falls below ~140°C. Current limit triggers at 6.1–8.75 A depending on temperature, causing foldback or hiccup mode. UVLO disables operation below ~6.5 V input, preventing unstable startup.
LM2677SD-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Not For New Designs
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 37V
- 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-ADJ FAQ
1.How can I place an order for LM2677SD-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2677SD-ADJ 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-ADJ reliable?
The price and inventory of LM2677SD-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2677SD-ADJ is usually 5 days.
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LM2677SD-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2677SD-ADJ 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-ADJ?
For technical support, including LM2677SD-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2677SD-ADJ requirements.
6.How does Aetrix verify that LM2677SD-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2677SD-ADJ 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-ADJ meets industry standards.
7.What is the process for return or replacement of LM2677SD-ADJ?
All LM2677SD-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2677SD-ADJ, 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-ADJ part is unused and in its original packaging.
Return procedure for LM2677SD-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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