My Inquiry
My Account
Texas Instruments LM2678S-ADJ/NOPB
- Part No.:
- LM2678S-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2678S-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:853
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2678S-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator with 5A output capability, 8V–40V input range, and adjustable output (1.2V–37V). It integrates a 120mΩ DMOS high-side switch, 260kHz fixed-frequency oscillator, and ±2% output voltage tolerance over full line/load/temperature. Used in industrial power supplies requiring high-efficiency (>90%) preregulation.
For engineers reviewing the LM2678S-ADJ/NOPB datasheet, LM2678S-ADJ/NOPB pinout, LM2678S-ADJ/NOPB application, or LM2678S-ADJ/NOPB equivalent, key selection criteria include its 5A continuous output, thermal shutdown protection, ON/OFF control interface, and compatibility with standard off-the-shelf inductors and Schottky diodes per TI's SIMPLE SWITCHER design methodology.
Technical Context
The LM2678S-ADJ/NOPB implements a voltage-mode PWM buck controller with internal 260kHz oscillator and integrated 120mΩ DMOS high-side switch. Feedback is sensed at the FB pin using an external resistor divider to set output voltage between 1.2V and 37V, with VFB = 1.21V (±1.1%) over –40°C to 125°C.
It operates in continuous conduction mode (CCM) up to 5A load, supports shutdown via ON/OFF pin (threshold 1.4V), and delivers 50μA standby current when disabled. Thermal shutdown and cycle-by-cycle current limiting (6.1A–8.75A) provide robust fault protection across its –40°C to 125°C junction temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5A continuous - supports high-power loads without external current boosting. |
| Input Voltage Range | 8V to 40V - enables direct use with 12V/24V industrial rails and battery systems. |
| Output Voltage Range | 1.2V to 37V adjustable - configured via external resistor divider on FB pin. |
| Switch RDS(ON) | 0.12Ω typical at 25°C - minimizes conduction loss for >90% efficiency at full load. |
| Oscillator Frequency | 260kHz fixed - enables use of compact, low-cost off-the-shelf inductors (e.g., 10µH). |
| Feedback Voltage | 1.21V ±1.1% - sets precise output regulation accuracy independent of input/load variation. |
| Standby Current | 50µA max - allows low-power system sleep modes without auxiliary LDOs. |
| Thermal Shutdown | Active above 160°C junction - protects against sustained overload or poor heatsinking. |
Pinout & Package
LM2678S-ADJ/NOPB is supplied in the KTW (TO-263-7) package: 10.1mm × 15.24mm thermally enhanced surface-mount outline with exposed DAP (die attach paddle) tied to GND for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch Output | Drain node of internal DMOS FET; connects to inductor and cathode of external Schottky diode - high dv/dt node requiring careful layout. |
| 2 (IN) | Input Supply | Main power input (8–40V); must be bypassed with low-ESR capacitor placed adjacent to pin to minimize switching noise coupling. |
| 3 (CB) | Bootstrap Capacitor | Connects to SW via 100nF ceramic capacitor to generate gate drive voltage >VIN for full FET enhancement. |
| 4 (GND) | Power Ground | Primary return path for input/output capacitors and IC ground; requires low-inductance connection to DAP and system ground plane. |
| 5 (NC) | No Connect | Internally unconnected; must remain floating - no routing or soldering allowed. |
| 6 (FB) | Feedback Input | Senses output voltage via external resistor divider; high-impedance (85nA bias) node sensitive to EMI - keep trace short and away from SW node. |
| 7 (ON/OFF) | Enable Control | Logic-level shutdown input; <0.8V disables regulator (50µA ISTBY), >1.4V enables operation; internal 20µA pull-up allows open-circuit enable. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120mΩ DMOS Switch | Eliminates need for external high-current MOSFET and driver, reducing BOM count and PCB area. |
| 260kHz Fixed-Frequency PWM | Enables predictable EMI filtering and consistent inductor sizing across designs using TI-recommended parts. |
| ±2% Output Tolerance | Guarantees stable output under full line (8–40V), load (0–5A), and temperature (–40°C to 125°C) conditions without trimming. |
| ON/OFF Pin with 50µA Standby | Supports system-level power sequencing and low-quiescent-power sleep states without external logic or regulators. |
| Built-in Protection | Includes thermal shutdown, cycle-by-cycle current limit (6.1–8.75A), and safe SOA operation - reduces need for external fault monitoring. |
| SIMPLE SWITCHER® Design Support | Compatible with WEBENCH® Power Designer for automated component selection, schematic generation, and performance simulation. |
Applications
| Industrial Power Preregulator | Battery Charger Front-End |
|---|---|
Use Scenario: Preconditioning 24V bus to 5V/3.3V for downstream digital logic and analog circuitry in PLCs and motor drives. IC Role / Device Role / Timing Role: Primary buck converter providing regulated intermediate rail with high efficiency and fast transient response. Use Value: Delivers 5A at >90% efficiency across wide input range, reducing heat sink requirements and enabling compact enclosure designs. | Use Scenario: Generating constant-current/constant-voltage charging profiles for 12V lead-acid or LiFePO4 battery banks from variable solar or AC/DC sources. IC Role / Device Role / Timing Role: Adjustable-output buck controller regulating charge voltage (e.g., 14.4V) and current via feedback loop configuration. Use Value: Adjustable VOUT (1.2–37V) and precise ±2% regulation ensure accurate battery voltage setpoints and long-term state-of-charge stability. |
| High-Efficiency DC-DC Module | Embedded System Power Supply |
Use Scenario: Integration into DIN-rail mountable 24V-to-5V/12V modules for factory automation sensors and I/O interfaces. IC Role / Device Role / Timing Role: Core power conversion element in self-contained, thermally optimized module with minimal external components. Use Value: TO-263-7 package with exposed DAP enables >35°C/W thermal resistance on 1 oz. copper, supporting 5A continuous without forced air. | Use Scenario: Local point-of-load regulation for FPGA, microcontroller, or DSP cores requiring clean, stable 1.8V or 2.5V rails from a 12V backplane. IC Role / Device Role / Timing Role: High-current buck regulator delivering tightly regulated output with low ripple (<20mV) and fast load-step response. Use Value: 260kHz switching frequency and internal compensation allow stable operation with low-ESR ceramic output capacitors, minimizing board space. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-ADJ/NOPB | 3A output, 150kHz switching, higher RDS(ON) (0.22Ω), wider VIN (4.5–40V) | Limited to ≤3A loads; lower efficiency at 5A due to higher conduction loss and reduced thermal headroom. | Select when cost sensitivity outweighs current requirement, or when lower EMI at 150kHz is prioritized over peak output capability. |
| TPS54560DGQ | 5A synchronous buck, 100V max VIN, 2.5–60V input, integrated high/low-side FETs, 3.5–600kHz adjustable frequency | Supports higher input voltages and offers programmable frequency; requires external compensation but provides tighter VOUT accuracy (±1%). | Select for ultra-wide input (e.g., automotive transients) or where synchronous rectification improves light-load efficiency and eliminates catch diode. |
Compared with LM2678S-ADJ/NOPB, LM2596S-ADJ/NOPB trades 2A output capacity and thermal margin for lower cost and simpler magnetics, while TPS54560DGQ extends input voltage range and adds synchronous operation at the expense of increased design complexity and external compensation requirements.
Availability
LM2678S-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charging systems, and embedded DC-DC conversion requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2678S-ADJ/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 leader specializing in analog, embedded processing, and power management technologies, with decades of experience in high-reliability power conversion ICs.
The LM2678 series belongs to TI's SIMPLE SWITCHER® family - designed specifically to simplify high-efficiency buck regulator implementation using minimal external components and industry-standard passives.
FAQ
What is the maximum output current supported by the LM2678S-ADJ/NOPB?
The LM2678S-ADJ/NOPB is rated for 5A continuous output current under recommended operating conditions (TJ ≤ 125°C, adequate PCB copper area). Its internal current limit is 6.1A minimum at 25°C, derating to 5.75A at –40°C to 125°C. Sustained 5A operation requires proper thermal management using the TO-263-7 package's exposed DAP connected to a ≥1 oz. copper ground plane.
Does the LM2678S-ADJ/NOPB require an external catch diode?
Yes, the LM2678S-ADJ/NOPB requires an external Schottky diode connected from the SW pin (Pin 1) to GND. This diode provides the freewheeling path for inductor current during the switch OFF period. TI recommends low-forward-voltage, high-current Schottky diodes (e.g., 3A–5A rating) with <0.5V VF to maintain high efficiency - the LM2678S-ADJ/NOPB does not integrate synchronous rectification.
How is the output voltage set on the LM2678S-ADJ/NOPB?
The output voltage of the LM2678S-ADJ/NOPB is set using a resistor divider from VOUT to GND, with the midpoint connected to the FB pin (Pin 6). The device regulates to maintain 1.21V at FB, so VOUT = 1.21V × (1 + R1/R2). For example, R1 = 10kΩ and R2 = 1.3kΩ yields ~10.5V. The datasheet specifies VFB tolerance as ±1.1% over temperature, ensuring tight output accuracy.
What thermal considerations apply to the LM2678S-ADJ/NOPB in TO-263-7 (KTW) package?
In the KTW package, the LM2678S-ADJ/NOPB achieves RθJA ≈ 35°C/W with 0.4896 in² (3.6× package area) of 1 oz. copper, and 26°C/W with 1.0064 in² (7.4× package area). The exposed DAP (Pin 4) must be soldered to a solid ground plane with multiple thermal vias. Junction temperature must stay ≤125°C; exceeding this triggers thermal shutdown. Layout must minimize trace inductance on IN, SW, and GND paths to reduce switching losses and EMI.
Can the LM2678S-ADJ/NOPB be synchronized to an external clock?
No, the LM2678S-ADJ/NOPB uses an internal fixed-frequency 260kHz oscillator and does not support external clock synchronization. Its timing is fully self-contained, with oscillator frequency tolerance specified as ±11% over temperature. For designs requiring frequency coordination (e.g., to avoid beat frequencies), alternative regulators such as the TPS54560DGQ or LM5115 must be selected.
LM2678S-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tube
- Product Status:
- Active
- 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:
- TO-263 (DDPAK-7)
LM2678S-ADJ/NOPB FAQ
1.How can I place an order for LM2678S-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2678S-ADJ/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 LM2678S-ADJ/NOPB reliable?
The price and inventory of LM2678S-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2678S-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2678S-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2678S-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2678S-ADJ/NOPB?
LM2678S-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2678S-ADJ/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 LM2678S-ADJ/NOPB?
For technical support, including LM2678S-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2678S-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2678S-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2678S-ADJ/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 LM2678S-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2678S-ADJ/NOPB?
All LM2678S-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2678S-ADJ/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 LM2678S-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2678S-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2678S-ADJ/NOPB Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
