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Texas Instruments LM2670SDX-ADJ
- Part No.:
- LM2670SDX-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2670SDX-ADJ.pdf
- Description:
- IC REG BUCK ADJ 3A 14VSON
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM2670SDX-ADJ from Texas Instruments is a monolithic step-down (buck) DC-DC voltage regulator IC delivering up to 3 A output current, featuring an internal 150-mΩ DMOS high-side switch, adjustable output voltage range of 1.2 V to 37 V, 260-kHz fixed-frequency PWM control, and ±2% output voltage tolerance over line, load, and temperature. It serves as a primary power conversion stage in industrial power supplies and battery-fed systems requiring high efficiency (>90%) and wide input range.
For engineers reviewing the LM2670SDX-ADJ datasheet, LM2670SDX-ADJ pinout, LM2670SDX-ADJ application, or LM2670SDX-ADJ equivalent, key selection criteria include its 8 V–40 V input range, external sync capability (280–400 kHz), 50-µA shutdown quiescent current, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and Schottky diodes in buck topology designs.
Technical Context
The LM2670SDX-ADJ implements a voltage-mode PWM controller with a fixed 260-kHz internal oscillator and supports external synchronization above 280 kHz. Its integrated high-side DMOS switch enables continuous conduction mode operation up to 3 A while maintaining efficiency >90% across input voltages from 8 V to 40 V.
Feedback is sensed via a precision two-stage amplifier referenced to an internal 1.2-V bandgap, enabling accurate output regulation using an external resistor divider. The ON/OFF pin provides TTL/CMOS-compatible enable control with 1.4-V threshold and 20-µA input bias, allowing seamless integration into system-level power sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A maximum continuous; supports stable regulation under full-load conditions without external current-sense components. |
| Input Voltage Range | 8 V to 40 V; accommodates 12-V, 24-V, and 36-V industrial bus rails and wide-range battery inputs. |
| Output Voltage Range | 1.2 V to 37 V (adjustable); set precisely via external resistor divider on FB pin, enabling flexible system-level voltage scaling. |
| Switching Frequency | 260 kHz fixed internal oscillator; allows use of compact, low-DCR inductors while balancing EMI and efficiency trade-offs. |
| Efficiency | Up to 94% at 12-V input / 5-V output / 5-A load; achieved via low RDS(on) (150 mΩ) DMOS switch and optimized gate drive. |
| Quiescent Current | 50 µA in shutdown mode (ON/OFF = LOW); minimizes standby power loss in always-on or battery-backed systems. |
| Output Accuracy | ±2% over full line, load, and temperature (–40°C to +125°C); ensures reliable downstream logic and analog circuit operation. |
Pinout & Package
LM2670SDX-ADJ is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad for enhanced heat dissipation. Body size is 10.10 mm × 8.89 mm. Pin 1 is Switch Output (VSW), pin 2 is Input (VIN), pin 3 is CBOOST/CB, pin 4 is GND, pin 5 is SYNC, pin 6 is Feedback (FB), and pin 7 is ON/OFF. Pins marked NC are not internally connected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VSW) | Switch Output | Drain node of internal high-side DMOS FET; connects directly to inductor and Schottky diode cathode; switches between VIN and ~–0.4 V during OFF state. |
| 2 (VIN) | Input Supply | Main power input (8–40 V); supplies both load energy and internal bias; requires low-ESR bypass capacitor placed adjacent to this pin. |
| 3 (CBOOST) | Bootstrap Capacitor | Connects to VSW via 100-nF ceramic capacitor; generates gate-drive voltage >VIN to fully enhance internal high-side FET and minimize conduction loss. |
| 4 (GND) | Power Ground | Common return path for input capacitor, output capacitor, and internal circuitry; must be tied to low-impedance PCB ground plane. |
| 5 (SYNC) | External Clock Input | Accepts TTL/CMOS clock (280–400 kHz); overrides internal oscillator to fix ripple frequency for predictable EMI filtering and spectrum positioning. |
| 6 (FB) | Feedback Sense | High-impedance input (85 nA bias) to error amplifier; connects to resistor divider from VOUT to set regulated output voltage per VOUT = 1.2 V × (1 + R1/R2). |
| 7 (ON/OFF) | Enable Control | TTL-compatible digital input; ≥1.4 V enables regulation, ≤0.8 V disables output and reduces quiescent current to 50 µA; internal 20-µA pull-up. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 150-mΩ DMOS High-Side Switch | Eliminates need for external MOSFET and driver; reduces BOM count and layout complexity while sustaining 3-A continuous output. |
| Adjustable Output (1.2 V–37 V) | Enables single IC to support diverse system rail requirements (e.g., 1.8 V for FPGA core, 3.3 V for I/O, 12 V for fans) via two external resistors. |
| External Sync Capability (280–400 kHz) | Allows precise alignment of switching frequency across multiple converters to avoid beat frequencies and simplify EMI filter design. |
| Thermal Shutdown & Current Limit | Protects against overload and overheating without external circuitry; current limit threshold is 3.8–5.25 A over temperature. |
| 50-µA Shutdown Quiescent Current | Supports ultra-low-power sleep modes in portable and remote-sensor applications where battery life is critical. |
Applications
| Industrial Power Supplies | Battery Charger Pre-Regulator |
|---|---|
|
Use Scenario: Primary DC-DC conversion stage in DIN-rail mounted PLC power modules accepting 24-V or 36-V input and delivering 5-V/3-A for logic and communication subsystems. IC Role / Device Role / Timing Role: Buck regulator IC providing isolated, efficient, and thermally robust voltage conversion with built-in current limiting and thermal protection. Use Value: Delivers >92% efficiency at full load and maintains ±2% output accuracy across –40°C to +85°C ambient, reducing heatsink requirements and improving system reliability. |
Use Scenario: Intermediate voltage regulation stage in multi-cell Li-ion battery chargers, stepping down 32-V max pack voltage to 12.6-V constant-voltage charge rail. IC Role / Device Role / Timing Role: Adjustable-output buck controller managing bulk power delivery before linear post-regulation, synchronized to avoid interference with USB or CAN communication clocks. Use Value: External sync input (pin 5) enables fixed 350-kHz switching aligned with host microcontroller timing, minimizing conducted EMI in sensitive charging circuits. |
| Communications Equipment | Automotive Aftermarket Electronics |
|
Use Scenario: Point-of-load supply for RF transceiver modules in base station radios, converting 28-V nominal input to 3.3-V/2-A for analog front-end and digital signal processors. IC Role / Device Role / Timing Role: High-efficiency synchronous buck regulator with tight output tolerance and low noise performance, supporting stable PLL reference and ADC reference voltages. Use Value: 260-kHz fixed frequency and low output ripple (<20 mVpp) ensure clean power for RF sections, while thermal shutdown prevents damage during antenna VSWR faults. |
Use Scenario: Power management IC in vehicle-mounted dashcams or telematics units operating from 9–16-V automotive battery with cold-crank tolerance down to 6 V. IC Role / Device Role / Timing Role: Wide-input buck regulator delivering stable 5-V/3-A output despite engine cranking dips and load-dump transients. Use Value: 8-V minimum input rating and 40-V absolute max withstand capability allow direct connection to battery without pre-regulation, simplifying front-end design. |
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/NOPB | Lower 1.5-A output current, 150-kHz switching frequency, no external sync capability, higher RDS(on) (220 mΩ). | Suitable for lower-power applications (<2 A) where EMI constraints are less stringent and fixed-frequency operation suffices. | Select when cost sensitivity outweighs current capability and sync flexibility; verify thermal margin at full load. |
| TPS54302DDCR | Higher 3-A continuous rating, 2.5-MHz switching, integrated soft-start, but narrower 4.5–28-V input range and no thermal shutdown flag. | Better suited for space-constrained PCBs needing high-frequency operation and fast transient response, but not for 36-V industrial inputs. | Choose for compact designs with <28-V input and need for fast load-step recovery; confirm input voltage compliance in battery or PoE applications. |
Compared with LM2670SDX-ADJ, LM2596SX-ADJ/NOPB offers lower cost and simpler layout but sacrifices current headroom and sync control; TPS54302DDCR delivers superior transient response and density but lacks the 40-V input tolerance and thermal fault reporting essential for harsh-environment deployments.
Availability
LM2670SDX-ADJ is available at Aetrix Electronics and suitable for industrial power supplies, battery charger pre-regulators, communications equipment, and automotive aftermarket electronics requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2670SDX-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, with decades of experience in high-reliability power conversion ICs.
The LM2670 series belongs to TI's SIMPLE SWITCHER® portfolio, designed specifically for ease-of-use in non-isolated DC-DC buck applications-emphasizing minimal external components, robust thermal behavior, and broad industrial operating ranges.
FAQ
What is the maximum input voltage rating for LM2670SDX-ADJ?
The LM2670SDX-ADJ has an absolute maximum input voltage rating of 45 V, with recommended operation from 8 V to 40 V. Exceeding 40 V continuously risks exceeding thermal limits or triggering internal protection circuits, even if within absolute max ratings. For sustained 40-V operation, ensure adequate PCB copper area and airflow per TI's thermal metrics for the TO-263 package.
Can LM2670SDX-ADJ be synchronized to an external clock, and what are the valid frequency limits?
Yes, LM2670SDX-ADJ supports external synchronization via pin 5 (SYNC). Valid external clock frequencies range from 280 kHz to 400 kHz - strictly higher than the internal oscillator's maximum of 280 kHz. Frequencies below 280 kHz may cause erratic operation or failure to lock. TI recommends AC-coupling the clock source through a 100-pF capacitor and 1-kΩ pull-down resistor to ensure clean edge transitions.
What is the feedback reference voltage and how is output voltage set for LM2670SDX-ADJ?
The LM2670SDX-ADJ uses an internal 1.2-V precision bandgap reference at the FB pin. Output voltage is set by an external resistor divider: VOUT = 1.2 V × (1 + R1/R2), where R2 connects from FB to GND and R1 from VOUT to FB. Typical bias current at FB is 85 nA, so resistor values should keep divider current ≥100× that (e.g., R1 + R2 ≤200 kΩ) to minimize error.
Does LM2670SDX-ADJ include thermal protection, and how does it behave under overload?
Yes, LM2670SDX-ADJ integrates thermal shutdown that disables switching when junction temperature exceeds approximately 165°C. Recovery occurs automatically once temperature falls below ~145°C hysteresis. Under sustained overload, current limiting activates first (trip point 3.8–5.25 A), holding peak inductor current constant until thermal shutdown intervenes - preventing device destruction during short-circuit or excessive ambient conditions.
What package type is used for LM2670SDX-ADJ, and what are its thermal characteristics?
LM2670SDX-ADJ is supplied in the 7-pin TO-263 (KTW) package with an exposed thermal pad. With 3.6× package-area copper (0.4896 in²), its RθJA is 35°C/W; with 7.4× area (1.0064 in²), it drops to 26°C/W. The thermal pad must be soldered to a solid copper pour connected to ≥4 thermal vias to an inner ground plane to achieve rated performance and sustain 3-A continuous output at elevated ambient temperatures.
LM2670SDX-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- 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:
- 14-VSON (5x6)
LM2670SDX-ADJ FAQ
1.How can I place an order for LM2670SDX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2670SDX-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 LM2670SDX-ADJ reliable?
The price and inventory of LM2670SDX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2670SDX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2670SDX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2670SDX-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2670SDX-ADJ?
LM2670SDX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2670SDX-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 LM2670SDX-ADJ?
For technical support, including LM2670SDX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2670SDX-ADJ requirements.
6.How does Aetrix verify that LM2670SDX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2670SDX-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 LM2670SDX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2670SDX-ADJ?
All LM2670SDX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2670SDX-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 LM2670SDX-ADJ part is unused and in its original packaging.
Return procedure for LM2670SDX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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