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Texas Instruments LM2670T-ADJ
- Part No.:
- LM2670T-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2670T-ADJ.pdf
- Description:
- IC REG BUCK ADJ 3A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:2,287
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Product details
Overview
LM2670T-ADJ from Texas Instruments is a monolithic step-down (buck) DC-DC voltage regulator IC delivering up to 3 A output current, featuring a 150-mΩ DMOS high-side switch, adjustable output voltage range of 1.2 V to 37 V, 260-kHz fixed-frequency internal oscillator, and ±2% output voltage tolerance over full line/load/temperature conditions. It serves as a high-efficiency (>90%) preregulator in industrial power supplies and battery-charged systems.
For engineers reviewing the LM2670T-ADJ datasheet, LM2670T-ADJ pinout, LM2670T-ADJ application, or LM2670T-ADJ equivalent, key selection criteria include input voltage range (8–40 V), standby quiescent current (50 µA), external sync capability (280–400 kHz), thermal shutdown protection, and feedback bias current (85 nA) for precision output setting.
Technical Context
The LM2670T-ADJ implements a current-mode PWM controller with an integrated 150-mΩ DMOS high-side switch and internal 260-kHz oscillator. Its feedback loop uses a two-stage high-gain amplifier referenced to 1.21 V nominal internal reference, enabling precise output regulation via external resistor divider.
It supports both self-oscillating operation and external synchronization (280–400 kHz), with dedicated SYNC pin logic that resets the internal ramp oscillator on each rising edge. Shutdown mode is activated when ON/OFF pin voltage falls below 0.8 V, reducing supply current to 50 µA while maintaining thermal and overcurrent protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output current | Up to 3 A continuous load capability with internal current limit set at 3.8–5.25 A. |
| Input voltage range | 8 V to 40 V - supports wide-range industrial and battery-derived inputs without pre-regulation. |
| Output voltage range | 1.2 V to 37 V - programmable via external resistor divider connected to FB pin. |
| Switching frequency | 260 kHz fixed internal oscillator; externally synchronizable from 280 kHz to 400 kHz for EMI control. |
| Feedback reference | 1.21 V typical internal reference voltage - sets output accuracy and stability across temperature. |
| Quiescent current | 6 mA operating IQ; drops to 50 µA in shutdown - enables low-power standby in battery systems. |
| Efficiency | Up to 94% at 12-V input / 5-V output / 5-A load - achieved via low RDS(ON) (0.15 Ω) DMOS switch. |
| Thermal protection | Integrated thermal shutdown with hysteresis - prevents damage during sustained overload or poor heatsinking. |
Pinout & Package
LM2670T-ADJ is packaged in TO-263 (KTW) - a 7-pin surface-mount DDPAK with exposed thermal pad (10.10 mm × 8.89 mm). The package enables high-current thermal performance with PCB copper area optimization.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain node of internal high-side DMOS FET - connects directly to inductor and Schottky diode cathode; switches between VIN and ~−0.5 V. |
| 2 (VIN) | Input supply | Main power input (8–40 V); supplies both load path and internal bias - requires low-ESR bypass capacitor placed adjacent to pin. |
| 3 (CBOOST) | Bootstrap capacitor connection | Connects 100-nF ceramic capacitor to SW pin - provides gate drive voltage > VIN to fully enhance high-side FET and minimize conduction loss. |
| 4 (GND) | Power ground | Primary return path for input/output capacitors and internal circuitry - must be tied to low-impedance PCB ground plane. |
| 5 (SYNC) | External clock input | Accepts TTL/CMOS-compatible signal (≥3 V) to override internal 260-kHz oscillator - enables precise ripple frequency control for EMI filtering. |
| 6 (FB) | Feedback sense input | High-impedance (85 nA bias) input to error amplifier - connected to resistor divider to set output voltage; internal 1.21-V reference enables 1.2–37 V adjustment. |
| 7 (ON/OFF) | Enable control input | Logic-level enable: >1.4 V = active, <0.8 V = shutdown; internal 20-µA pull-up allows floating for default ON operation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 150-mΩ DMOS high-side switch | Enables ≥90% efficiency at 3-A load without external MOSFET - reduces BOM count and layout complexity. |
| ±2% output voltage tolerance | Guaranteed over full line (8–40 V), load (100 mA–3 A), and temperature (–40°C to +125°C) - eliminates need for post-production trimming. |
| External synchronization (280–400 kHz) | Allows fixed-frequency EMI management and multi-rail system clock alignment - avoids beat frequencies in dense PCB layouts. |
| 50-µA shutdown quiescent current | Supports ultra-low-power standby in portable/battery-powered equipment - extends operational runtime during idle states. |
| Internal thermal shutdown & current limiting | Provides autonomous fault protection without external circuitry - ensures robustness under short-circuit or overheating conditions. |
| Simple design with off-the-shelf components | Validated inductor/capacitor/diode combinations available from Renco, Pulse, Coilcraft - accelerates time-to-prototype by >50%. |
Applications
| Industrial Power Supply Preregulator | Battery Charger Front-End |
|---|---|
|
Use Scenario: Converts unregulated 24-V or 36-V industrial bus to 5-V/3.3-V intermediate rail for downstream LDOs and digital ICs. IC Role / Device Role / Timing Role: Primary buck regulator providing stable, high-current intermediate voltage with minimal external components. Use Value: Delivers >92% efficiency at 24-V input/5-V output/2-A load - reduces heat sink size and improves system power density. |
Use Scenario: Steps down variable 12–40-V automotive or lead-acid battery source to constant-current/constant-voltage charging profile for Li-ion packs. IC Role / Device Role / Timing Role: Adjustable-output buck controller regulating charge voltage (e.g., 4.2 V per cell) with precise feedback and thermal foldback. Use Value: ±2% output tolerance and 50-µA shutdown enable accurate CV phase control and low-quiescent maintenance charging. |
| Communications Equipment Power | Radios and RF Transceivers |
|
Use Scenario: Powers FPGA I/O banks and analog front-ends in base station radios requiring clean, low-noise 1.8-V or 2.5-V rails. IC Role / Device Role / Timing Role: Synchronized buck converter locked to system master clock to eliminate switching noise interference in sensitive analog paths. Use Value: External SYNC pin enables ripple frequency positioning away from critical IF bands - simplifies EMI filter design and passes CISPR-22 Class B. |
Use Scenario: Supplies PA bias and synthesizer VCO rails in handheld transceivers where compact size and thermal resilience are critical. IC Role / Device Role / Timing Role: High-efficiency, thermally robust buck regulator operating from single-cell Li-ion (3.0–4.2 V) or dual-cell (6–8.4 V) sources. Use Value: TO-263 package with exposed thermal pad sustains 3-A load at +85°C ambient - eliminates need for forced air cooling in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2671-ADJ | 2.5-A rated output current; identical pinout, package, and feature set except lower current limit (3.2–4.2 A vs. 3.8–5.25 A). | Suitable for ≤2.5-A loads where thermal margin is less constrained; not recommended for sustained 3-A operation. | Select LM2671-ADJ only if load current remains below 2.5 A and board layout cannot accommodate higher thermal dissipation. |
| LM2596-ADJ | 3-A rated but uses bipolar transistor switch (higher RCE(sat)); 150-kHz fixed frequency; no SYNC pin; ±4% output tolerance. | Limited to cost-sensitive, non-safety-critical applications where efficiency >85% and EMI control are secondary. | Choose LM2596-ADJ only for legacy designs or budget-limited projects accepting lower accuracy, higher heat, and no sync capability. |
Compared with LM2671-ADJ and LM2596-ADJ, the LM2670T-ADJ delivers higher current capability, tighter output tolerance (±2% vs. ±4%), and external synchronization - making it optimal for thermally demanding, EMI-sensitive, or precision-regulated industrial and communications power rails.
Availability
LM2670T-ADJ is available at Aetrix Electronics and suitable for industrial power supplies, battery charger front-ends, communications equipment, and RF transceiver power systems requiring stable component supply and long-term manufacturability.
Supply support for LM2670T-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 expertise in high-reliability power conversion ICs.
The LM2670 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use, high-efficiency DC-DC conversion in industrial, telecom, and battery-powered applications without requiring complex compensation networks.
FAQ
What is the maximum input voltage rating for LM2670T-ADJ?
The absolute maximum input voltage for LM2670T-ADJ is 45 V, but the recommended operating range is 8 V to 40 V. Operation above 40 V risks exceeding safe junction temperature and may trigger thermal shutdown. For reliable long-term use, maintain VIN ≤ 40 V with adequate input capacitance and thermal management.
How do I set the output voltage for LM2670T-ADJ?
LM2670T-ADJ output voltage is set using a resistor divider from VOUT to GND, with the midpoint connected to the FB pin. The formula is VOUT = 1.21 V × (1 + R1/R2), where R2 connects FB to GND. A typical configuration uses R2 = 1.21 kΩ and R1 = (VOUT − 1.21) × 1.21 kΩ/1.21 V - ensuring FB bias current (85 nA) introduces negligible error.
Does LM2670T-ADJ support external clock synchronization?
Yes, LM2670T-ADJ supports external synchronization via the SYNC pin (Pin 5). An external TTL/CMOS clock (280–400 kHz) can replace the internal 260-kHz oscillator. The external signal must exceed 3 V and be AC-coupled with a 100-pF capacitor and 1-kΩ pull-down resistor - enabling precise ripple frequency control for EMI-sensitive applications.
What is the thermal performance of LM2670T-ADJ in TO-263 package?
In the TO-263 (KTW) package with 0.4896 in² copper area, LM2670T-ADJ achieves RθJA = 35°C/W. With 1.0064 in² copper, RθJA drops to 26°C/W. The exposed thermal pad must be soldered to PCB ground plane - achieving ≤125°C junction temperature at 3-A load and 85°C ambient requires ≥0.5 in² copper and optional airflow.
Can LM2670T-ADJ operate in shutdown mode with zero load?
Yes, LM2670T-ADJ enters shutdown mode when the ON/OFF pin voltage falls below 0.8 V, drawing only 50 µA from VIN - independent of output load. This state maintains full thermal and overcurrent protection while minimizing standby power, making it ideal for battery-backed systems requiring extended sleep intervals.
LM2670T-ADJ 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:
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2670T-ADJ FAQ
1.How can I place an order for LM2670T-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2670T-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 LM2670T-ADJ reliable?
The price and inventory of LM2670T-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2670T-ADJ is usually 5 days.
3.What payment methods are accepted for LM2670T-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2670T-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2670T-ADJ?
LM2670T-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2670T-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 LM2670T-ADJ?
For technical support, including LM2670T-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2670T-ADJ requirements.
6.How does Aetrix verify that LM2670T-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2670T-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 LM2670T-ADJ meets industry standards.
7.What is the process for return or replacement of LM2670T-ADJ?
All LM2670T-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2670T-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 LM2670T-ADJ part is unused and in its original packaging.
Return procedure for LM2670T-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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