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Texas Instruments LM2670SX-ADJ
- Part No.:
- LM2670SX-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2670SX-ADJ.pdf
- Description:
- IC REG BUCK ADJ 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,075
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Product details
Overview
LM2670SX-ADJ from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator IC delivering up to 3A output current with adjustable output voltage (1.2V to 37V), 260kHz fixed internal oscillator, 8V–40V input range, and ±2% output voltage tolerance over line/load/temperature. It integrates a 150mΩ DMOS high-side switch and supports external clock synchronization for EMI-sensitive communications power supplies.
For engineers reviewing the LM2670SX-ADJ datasheet, LM2670SX-ADJ pinout, LM2670SX-ADJ application, or LM2670SX-ADJ equivalent, key selection criteria include its adjustable feedback architecture, thermal shutdown and current limiting protection, 50µA standby quiescent current in shutdown mode, and compatibility with standard off-the-shelf inductors and Schottky diodes for rapid design implementation.
Technical Context
The LM2670SX-ADJ implements a voltage-mode PWM controller with an internal 260kHz oscillator and optional external SYNC input (280–400kHz), enabling precise ripple frequency control. Its feedback loop senses output voltage via a resistive divider at the FB pin and regulates using duty-cycle modulation of the integrated 150mΩ DMOS switch.
It operates in continuous conduction mode by default, supports shutdown via the ON/OFF pin (1.4V threshold), and features built-in thermal shutdown, cycle-by-cycle current limiting (3.6–5.4A), and bootstrap gate drive (CB pin) for high-side FET enhancement-enabling efficient high-current conversion without external driver circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3A maximum continuous load current - supports industrial and telecom power rails requiring robust current delivery. |
| Input Voltage Range | 8V to 40V - compatible with 12V/24V/36V battery and industrial bus systems without pre-regulation. |
| Output Voltage Range | 1.2V to 37V (adjustable via FB divider) - enables flexible system-level voltage scaling across diverse subsystems. |
| Feedback Reference Voltage | 1.21V typical (1.174V–1.246V over temp) - sets precision output regulation accuracy and defines resistor divider ratio. |
| Switching Frequency | 260kHz fixed internal oscillator; 280–400kHz externally synchronized - allows EMI filtering optimization and consistent spectral placement. |
| Quiescent Current | 50µA in shutdown (ON/OFF = low) - minimizes battery drain in always-on or low-power standby applications. |
| Efficiency | Up to 94% (at 12V→12V, 3A) - reduces thermal load and improves power density in enclosed or thermally constrained designs. |
| Thermal Protection | Integrated thermal shutdown - prevents damage during overload or poor heatsinking without external circuitry. |
Pinout & Package
LM2670SX-ADJ is available in KTW (TO-263-7) package: 10.1mm × 15.24mm body with exposed thermal pad, rated for high-power dissipation and PCB-mount thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch Output | Drain node of internal DMOS high-side switch - connects directly to inductor and external Schottky diode cathode; carries high-frequency pulsed current. |
| 2 (VIN) | Input Supply | Main power input (8–40V); supplies both load path and internal bias - requires low-ESR bypass capacitor placed adjacent to this pin. |
| 3 (CB) | Bootstrap Capacitor | Connects to SW via 100nF ceramic capacitor - generates gate-drive voltage >VIN to fully enhance internal MOSFET and minimize RDS(on) losses. |
| 4 (GND) | Power Ground | Primary return path for VIN, SW, FB, and ON/OFF - must be tied to low-impedance ground plane to suppress noise and ensure stability. |
| 5 (SYNC) | External Clock Input | Accepts TTL/CMOS clock (280–400kHz) to override internal oscillator - enables deterministic ripple frequency for EMI compliance and filter repeatability. |
| 6 (FB) | Feedback Sense | High-impedance input (85nA bias) monitoring output via resistive divider - sets regulated VOUT = 1.21V × (1 + R1/R2) for ADJ version. |
| 7 (ON/OFF) | Enable Control | Logic-level enable (1.4V threshold); <0.8V disables regulator, reducing IQ to 50µA - supports system-level power sequencing and sleep modes. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 150mΩ DMOS Switch | Enables high-efficiency 3A buck conversion without external MOSFETs or drivers - reduces BOM count and layout complexity. |
| Adjustable Output (1.2V–37V) | Supports wide-range system voltage requirements using only two external resistors - eliminates need for multiple fixed-output variants. |
| External SYNC Capability | Allows precise control of switching frequency (280–400kHz) for repeatable EMI filtering and spectrum positioning in radio/comm equipment. |
| 50µA Shutdown Quiescent Current | Minimizes battery leakage in portable or backup power systems - critical for >1-year shelf life in always-connected devices. |
| Built-in Thermal Shutdown & Current Limit | Provides autonomous fault protection without external sensing components - ensures reliability under overload, short-circuit, or thermal stress. |
| WEBENCH® Design Integration | Enables instant schematic generation, component selection, and performance simulation - accelerates time-to-prototype for power supply designers. |
Applications
| Industrial Motor Drive Power Supply | Telecom Base Station Preregulator |
|---|---|
Use Scenario: Provides stable 5V/12V intermediate rail for gate drivers, sensors, and microcontrollers in variable-speed motor controllers operating from 24V/48V DC bus. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated bus voltage to isolated logic and analog supply rails. Use Value: Delivers 3A continuous current with ±2% regulation and thermal shutdown - ensures reliable operation under motor surge loads and ambient temperature extremes (–40°C to 125°C). | Use Scenario: Serves as high-efficiency preregulator ahead of LDOs powering RF transceivers and baseband processors in 4G/5G small cells. IC Role / Device Role / Timing Role: High-current buck converter synchronized to system clock to avoid beat frequencies in sensitive RF front-ends. Use Value: External SYNC input enables fixed 350kHz operation - simplifies EMI filter design and guarantees consistent ripple spectrum across production units. |
| Battery-Powered Test Equipment | Automotive Infotainment System Supply |
Use Scenario: Generates adjustable 3.3V/5V rails from 12V lead-acid or LiFePO₄ battery in portable oscilloscopes and signal analyzers. IC Role / Device Role / Timing Role: Main DC-DC converter with programmable output and ultra-low shutdown current for extended battery runtime. Use Value: 50µA standby current and wide 8–40V input range allow direct battery connection without pre-buck - extends operational time between charges. | Use Scenario: Supplies 3.3V core voltage to MCU and display controller in automotive head units powered from 9–16V vehicle battery with cold-crank tolerance. IC Role / Device Role / Timing Role: Robust buck regulator with thermal shutdown and current limit - handles load dumps and cranking transients per ISO 7637-2. Use Value: 40V absolute max input rating and –40°C to 125°C junction range meet AEC-Q100 Grade 1 requirements for under-hood electronics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596SX-ADJ | Lower 1.5A output current, 150kHz fixed frequency, no SYNC input, higher RDS(on) (220mΩ) | Suitable for lower-power applications where EMI control and thermal margin are less critical | Select when cost sensitivity outweighs current capability and frequency flexibility needs |
| TPS54302DDAR | 3A output, 2.5V–28V input, 300kHz–2MHz adjustable frequency, integrated soft-start, smaller 8-pin SOIC package | Better suited for space-constrained designs requiring programmable frequency and enhanced transient response | Prefer when board area is limited and design requires fine-grained frequency tuning or soft-start control |
Compared with LM2596SX-ADJ, LM2670SX-ADJ delivers 2× output current and external sync capability for EMI control; versus TPS54302DDAR, it offers higher input voltage range (40V vs 28V) and TO-263 thermal performance but lacks programmable soft-start and smaller footprint.
Availability
LM2670SX-ADJ is available at Aetrix Electronics and suitable for industrial motor drives, telecom base station power supplies, battery-powered test equipment, and automotive infotainment systems requiring stable component supply and long-term manufacturability.
Supply support for LM2670SX-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 leader specializing in analog, embedded processing, and power management technologies, serving industrial, automotive, and communications markets.
The LM2670 series belongs to TI's SIMPLE SWITCHER® power converter family, designed to simplify high-efficiency DC-DC buck regulator implementation using minimal external components and industry-standard magnetics.
FAQ
What is the maximum input voltage rating for the LM2670SX-ADJ?
The LM2670SX-ADJ has an absolute maximum input voltage rating of 45V, with recommended operating range of 8V to 40V. Exceeding 40V continuously may trigger overvoltage protection or reduce reliability; operation at 45V is only permissible for transient conditions per datasheet Section 5.1.
How does the FB pin function in the LM2670SX-ADJ?
The FB pin on the LM2670SX-ADJ is a high-impedance input (85nA typical bias current) that senses the output voltage via an external resistive divider. For the ADJ version, VOUT = 1.21V × (1 + R1/R2), where 1.21V is the internal reference voltage - enabling precise programmable output regulation across the 1.2V–37V range.
Can the LM2670SX-ADJ synchronize to an external clock, and what are the valid frequency limits?
Yes, the LM2670SX-ADJ supports external synchronization via the SYNC pin (Pin 5). Valid input frequencies range from 280kHz to 400kHz - must exceed the internal oscillator's maximum of 280kHz to prevent erratic operation. The external clock must be TTL/CMOS-compatible and AC-coupled with a 100pF capacitor and 1kΩ pull-down resistor.
What thermal protection mechanisms are built into the LM2670SX-ADJ?
The LM2670SX-ADJ includes integrated thermal shutdown that disables the regulator when junction temperature exceeds ~165°C. Recovery occurs automatically once temperature falls below ~145°C hysteresis. This protection operates independently of external components and is documented in Section 6.4.1 of the LM2670SX-ADJ datasheet.
Is the LM2670SX-ADJ pin-compatible with other members of the LM2670 family?
Yes, all LM2670 variants - including LM2670SX-3.3, LM2670SX-5.0, LM2670SX-12, and LM2670SX-ADJ - share identical pinout and package options (KTW, NDZ, NHM). Only the feedback network differs: fixed versions tie FB directly to VOUT, while LM2670SX-ADJ requires an external resistor divider to set output voltage.
LM2670SX-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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):
- 1.2V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 3A
- 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)
LM2670SX-ADJ FAQ
1.How can I place an order for LM2670SX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2670SX-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 LM2670SX-ADJ reliable?
The price and inventory of LM2670SX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2670SX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2670SX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2670SX-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2670SX-ADJ?
LM2670SX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2670SX-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 LM2670SX-ADJ?
For technical support, including LM2670SX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2670SX-ADJ requirements.
6.How does Aetrix verify that LM2670SX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2670SX-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 LM2670SX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2670SX-ADJ?
All LM2670SX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2670SX-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 LM2670SX-ADJ part is unused and in its original packaging.
Return procedure for LM2670SX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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