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Texas Instruments LM2670SX-3.3
- Part No.:
- LM2670SX-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2670SX-3.3.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:4,045
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Product details
Overview
LM2670SX-3.3 from Texas Instruments is a monolithic 3-A synchronous step-down (buck) DC/DC voltage regulator with fixed 3.3-V output, 8–40-V input range, 260-kHz internal oscillator, ±2% output tolerance over line/load/temperature, and 150-mΩ DMOS high-side switch. It delivers >90% efficiency in telecom power supplies, industrial controllers, and battery-charged systems.
For engineers reviewing the LM2670SX-3.3 datasheet, LM2670SX-3.3 pinout, LM2670SX-3.3 application, or LM2670SX-3.3 equivalent, key selection criteria include its 3-A continuous output capability, external sync clock support (280–400 kHz), 50-µA shutdown current, thermal shutdown protection, and TO-263-7 package compatibility with high-power PCB layouts.
Technical Context
The LM2670SX-3.3 implements a current-mode PWM control architecture 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 an internal 1.23-V bandgap, enabling precise regulation without external resistors for the 3.3-V fixed-output variant.
Functional modes include active regulation (ON/OFF ≥1.4 V) and shutdown (ON/OFF ≤0.8 V), with 50-µA standby current. The SYNC pin accepts external TTL/CMOS clocks above 280 kHz to override the internal oscillator-enabling ripple frequency control for EMI-sensitive radio and communications equipment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±2% over –40°C to 125°C junction temperature, full line/load range - ensures stable logic rail generation without external feedback divider. |
| Input Voltage Range | 8 V to 40 V - supports wide industrial and automotive battery-derived inputs, including 12-V and 24-V nominal systems. |
| Continuous Output Current | 3 A - sustains full-rated load under thermal design with TO-263-7 package and ≥0.4896 in² copper area (RθJA = 35°C/W). |
| Switching Frequency | 260 kHz (internal) or 280–400 kHz (external sync) - enables consistent EMI filtering and predictable inductor sizing across production units. |
| Efficiency | Up to 94% at 12-VIN/3.3-VOUT/5-A (typical), >90% across operating range - reduces thermal load and improves system power density. |
| Quiescent Current | 50 µA in shutdown (ON/OFF = 0 V) - minimizes battery drain in always-on or low-power standby applications. |
| Switch RDS(ON) | 0.15 Ω (typ), 0.29 Ω (max at –40°C to 125°C) - directly determines conduction loss and thermal rise under full load. |
Pinout & Package
LM2670SX-3.3 is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad (10.10 mm × 8.89 mm), optimized for high-current thermal dissipation on standard PCBs.
| 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; carries high dv/dt switching waveform. |
| 2 (VIN) | Input supply | Main power input (8–40 V); must be bypassed with low-ESR capacitor placed adjacent to pin to minimize high-frequency noise coupling. |
| 3 (CBOOST) | Bootstrap capacitor | Connects 100-nF ceramic capacitor to SW pin to generate gate drive voltage >VIN for full enhancement of high-side FET. |
| 4 (GND) | Power ground | Primary return path for input/output capacitors and thermal pad - requires low-inductance connection to PCB ground plane. |
| 5 (SYNC) | External sync input | TTL/CMOS-compatible input (1.4-V threshold); when driven >280 kHz, overrides internal oscillator to fix ripple frequency for EMI control. |
| 6 (FB) | Feedback sense | Internally tied to 3.3-V reference - connect directly to output capacitor for fixed-output operation; no external resistor network required. |
| 7 (ON/OFF) | Enable control | Active-high enable (1.4-V threshold); floating or pulled high enables regulation; grounded disables output and reduces IQ to 50 µA. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous buck topology | Eliminates external freewheeling diode - reduces conduction loss and improves efficiency by ~3–5% vs. asynchronous designs. |
| Integrated 150-mΩ DMOS switch | Enables 3-A continuous output without external MOSFETs - simplifies BOM and layout while maintaining <1.5-W dissipation at full load. |
| ±2% output tolerance | Guaranteed over –40°C to 125°C, full line/load - meets tight regulation requirements for FPGA core rails and microprocessor I/O supplies. |
| External clock synchronization | Allows precise ripple frequency positioning between 280–400 kHz - critical for meeting CISPR-22/EN55022 conducted EMI limits in comms equipment. |
| Thermal shutdown + current limit | Protects against sustained overload or ambient overheating - latches off until reset via ON/OFF pin toggle or VIN cycle. |
Applications
| Industrial PLC Power Supply | Telecom Line Card Preregulator |
|---|---|
|
Use Scenario: Provides clean 3.3-V rail for microcontrollers, ADCs, and communication interfaces inside DIN-rail mounted programmable logic controllers operating from 24-V DC bus. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 24-V field power to isolated 3.3-V logic supply with minimal heat buildup in confined enclosures. Use Value: 94% peak efficiency and 50-µA shutdown current extend operational uptime and reduce cooling requirements in fanless industrial cabinets. |
Use Scenario: Generates stable 3.3-V supply for Ethernet PHYs and packet processors on carrier-grade line cards powered from –48-V telecom battery banks. IC Role / Device Role / Timing Role: High-reliability preregulator preceding LDOs, delivering low-noise 3.3-V rail synchronized to system clock to suppress beat frequencies in data transmission. Use Value: External SYNC capability locks switching ripple to 333 kHz - avoids interference with 10/100/1000BASE-T baseband signals and simplifies EMI filter design. |
| Battery-Powered Test Equipment | Automotive Infotainment Display Supply |
|
Use Scenario: Powers FPGA-based signal generators and spectrum analyzers running from 12-V Li-ion battery packs with variable state-of-charge (10–16.8 V). IC Role / Device Role / Timing Role: Wide-input buck converter maintaining regulated 3.3-V output across full battery discharge curve without brownout or dropout. Use Value: 8-V minimum input supports operation down to 10% battery capacity; 50-µA shutdown extends shelf life during storage or transport. |
Use Scenario: Supplies 3.3-V logic rail for LCD timing controllers and touch interface ICs in automotive head units powered from 12-V vehicle battery with load-dump transients. IC Role / Device Role / Timing Role: Robust primary DC/DC stage with built-in thermal shutdown and current limiting - withstands 40-V load-dump spikes per ISO 7637-2. Use Value: 40-V absolute max input rating and –40°C to 125°C operating range ensure reliability in under-hood and dashboard environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2671MX-3.3 | Same 3.3-V fixed output, but non-synchronous (requires external Schottky diode); 3-A rating; 260-kHz oscillator only - no SYNC pin. | Lacks external clock sync and has ~3% lower efficiency due to diode conduction loss - suitable where EMI control is not critical and cost is prioritized. | Select LM2671MX-3.3 only if board space allows external diode and ripple frequency control is unnecessary. |
| TPS54302DDCR | 3-A synchronous buck with 3.3-V fixed output, 4.5–28-V input, 2.5-MHz switching, integrated soft-start - no SYNC pin, smaller 6-pin SOT-23 package. | Lower input voltage ceiling (28 V vs. 40 V); higher frequency enables smaller magnetics but increases switching loss above 12-VIN. | Choose TPS54302DDCR for compact, low-input-voltage designs (<24 V) where PCB area is constrained and high-frequency operation is acceptable. |
Compared with LM2671MX-3.3, the LM2670SX-3.3 delivers higher efficiency and EMI control via sync; versus TPS54302DDCR, it supports wider input range and higher thermal robustness in TO-263 packaging - making it optimal for industrial and telecom 24/48-V systems requiring long-term reliability.
Availability
LM2670SX-3.3 is available at Aetrix Electronics and suitable for industrial automation power supplies, telecom infrastructure equipment, and battery-powered test instrumentation requiring stable component supply, long-lifecycle availability, and traceable sourcing.
Supply support for LM2670SX-3.3 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, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and communications markets.
The LM2670 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for engineers needing robust, easy-to-implement DC/DC conversion with minimal external components and guaranteed performance across harsh operating conditions.
FAQ
What is the maximum input voltage rating for LM2670SX-3.3?
The LM2670SX-3.3 has an absolute maximum input voltage rating of 45 V, with recommended operating range from 8 V to 40 V. Exceeding 40 V continuously risks exceeding thermal limits or violating safe operating area - especially under high ambient temperatures or poor PCB copper area. Always observe derating curves in Section 6.1 of the SNVS036K datasheet.
Does LM2670SX-3.3 require an external feedback resistor network?
No. The LM2670SX-3.3 is a fixed-output variant with internal feedback divider set for 3.3 V. Pin 6 (FB) must be connected directly to the output capacitor - no external resistors are needed. This eliminates tuning error and improves long-term stability compared to adjustable versions like LM2670T-ADJ.
Can LM2670SX-3.3 synchronize to an external clock below 280 kHz?
No. The LM2670SX-3.3 requires external SYNC frequency >280 kHz to reliably override the internal 260-kHz oscillator. Driving SYNC below 280 kHz may cause erratic switching, subharmonic oscillation, or failure to lock - per Section 7.3.5. For lower-frequency sync, consider the LM2678 series or discrete PLL-based solutions.
What thermal performance can be expected from LM2670SX-3.3 in TO-263 package?
In the KTW (TO-263-7) package with 0.4896 in² of 1-oz copper connected to the thermal pad, LM2670SX-3.3 achieves RθJA = 35°C/W. At 3-A load and 12-VIN, junction temperature rise is ~105°C above ambient - requiring ≤20°C ambient for safe 125°C max TJ. Full derating guidance is in Section 6.4 of SNVS036K.
Is LM2670SX-3.3 RoHS compliant and halogen-free?
Yes. LM2670SX-3.3 (KTW package) is RoHS-compliant and halogen-free per TI's official product change notices and material declarations. Lead finish is matte tin, and packaging conforms to JEDEC J-STD-020 moisture sensitivity level 3. Full compliance documentation is available via TI's Quality & Environmental page.
LM2670SX-3.3 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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- 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-3.3 FAQ
1.How can I place an order for LM2670SX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2670SX-3.3 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-3.3 reliable?
The price and inventory of LM2670SX-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2670SX-3.3 is usually 5 days.
3.What payment methods are accepted for LM2670SX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2670SX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2670SX-3.3?
LM2670SX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2670SX-3.3 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-3.3?
For technical support, including LM2670SX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2670SX-3.3 requirements.
6.How does Aetrix verify that LM2670SX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2670SX-3.3 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-3.3 meets industry standards.
7.What is the process for return or replacement of LM2670SX-3.3?
All LM2670SX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2670SX-3.3, 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-3.3 part is unused and in its original packaging.
Return procedure for LM2670SX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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