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Texas Instruments LM2670SX-3.3/NOPB
- Part No.:
- LM2670SX-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2670SX-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,305
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Product details
Overview
LM2670SX-3.3/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC switching regulator delivering up to 3 A output current with fixed 3.3 V output, 8–40 V input range, 260 kHz internal oscillator, ±2% output voltage tolerance, and 150 mΩ integrated DMOS high-side switch. It serves as a primary power conversion stage in industrial power supplies and battery-fed systems requiring high efficiency (>90%) and thermal robustness.
For engineers reviewing the LM2670SX-3.3/NOPB datasheet, LM2670SX-3.3/NOPB pinout, LM2670SX-3.3/NOPB application, or LM2670SX-3.3/NOPB equivalent, key selection criteria include its fixed 3.3 V output configuration, TO-263-7 (KTW) package with exposed thermal pad, external sync capability (280–400 kHz), 50 µA shutdown quiescent current, and built-in thermal shutdown/current limiting - all critical for reliable high-current buck conversion in space-constrained, thermally demanding designs.
Technical Context
The LM2670SX-3.3/NOPB implements a voltage-mode PWM controller with an integrated 150 mΩ DMOS high-side switch, operating in continuous conduction mode (CCM) at 260 kHz by default. Its feedback loop senses output voltage directly at the FB pin (shorted to VOUT for fixed versions), enabling precise regulation without external resistor dividers.
It supports external clock synchronization via the SYNC pin (5 V-tolerant, TTL/CMOS-compatible), overriding the internal oscillator when driven above 280 kHz - enabling EMI control and ripple frequency alignment in multi-rail systems. Shutdown is achieved by pulling the ON/OFF pin below 0.8 V, reducing supply current to 50 µA while maintaining full thermal and overcurrent protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | Fixed 3.3 V ±2% over –40°C to 125°C junction temperature and full line/load conditions - ensures stable logic rail generation without external feedback resistors. |
| Input voltage range | 8 V to 40 V - supports wide-input industrial, automotive, and telecom power buses without pre-regulation. |
| Max output current | 3 A continuous - enables single-chip conversion for mid-power FPGA, DSP, or microcontroller subsystems. |
| Switch RDS(ON) | 0.15 Ω typical - minimizes conduction loss and improves efficiency at high load currents (e.g., >86% at 12 VIN/3 A). |
| Oscillator frequency | 260 kHz fixed internal frequency - balances inductor size, efficiency, and EMI; externally synchronizable to 280–400 kHz for system-level noise coordination. |
| Shutdown current | 50 µA typical - enables ultra-low-power standby in battery-backed or energy-conscious applications. |
| Thermal shutdown | Integrated - protects against sustained overload or poor heatsinking in TO-263-7 package without external circuitry. |
Pinout & Package
LM2670SX-3.3/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with an exposed thermal pad (DAP) that must be soldered to a PCB ground plane for optimal thermal performance (RθJA = 35°C/W with 0.4896 in² copper). The package measures 10.1 mm × 15.24 mm including leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain node of internal high-side DMOS FET; connects to inductor and Schottky diode cathode - carries high-frequency AC switching current and requires low-inductance layout. |
| 2 (VIN) | Input supply | Main power input (8–40 V); must be bypassed with low-ESR capacitor placed adjacent to pin - path to GND must be shortest possible to minimize noise coupling. |
| 3 (CBOOST) | Bootstrap capacitor | Connects 100 nF ceramic capacitor to SW pin - provides gate drive voltage > VIN to fully enhance internal FET and minimize RDS(ON) losses. |
| 4 (GND) | Power ground | Primary return path for input/output capacitors and IC core - must connect directly to thermal pad and system ground plane to ensure stability and thermal dissipation. |
| 5 (SYNC) | Sync clock input | Accepts external 280–400 kHz TTL/CMOS clock (AC-coupled); overrides internal oscillator to align switching frequency across multiple rails or reduce EMI peaks. |
| 6 (FB) | Feedback sense | Internally tied to 3.3 V reference - shorted directly to output capacitor for fixed-output operation; no external divider required. |
| 7 (ON/OFF) | Enable control | Logic-level enable: >1.4 V = active, <0.8 V = shutdown (50 µA IQ); internal 20 µA pull-up allows floating for always-on use. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 150 mΩ DMOS switch | Eliminates need for external high-side MOSFET and driver, reducing BOM count and layout complexity while sustaining 3 A continuous output. |
| Fixed 3.3 V output configuration | Removes external feedback resistor network - simplifies design, improves accuracy (±2%), and enhances long-term stability versus adjustable variants. |
| External clock synchronization (280–400 kHz) | Enables deterministic ripple frequency placement for consistent EMI filtering and avoids beat frequencies in multi-converter systems. |
| 50 µA shutdown quiescent current | Supports low-power sleep modes in portable or remote equipment without compromising fast wake-up response (<100 µs typical). |
| Built-in thermal shutdown & current limit | Provides autonomous fault protection without external sensing components - triggers at ~160°C junction and limits peak switch current to ~4.5 A. |
Applications
| Industrial Power Supply | Battery Charger Pre-regulator |
|---|---|
|
Use Scenario: Converting 24 V DC bus to stable 3.3 V for PLC I/O modules and sensor interfaces in factory automation cabinets. IC Role / Device Role / Timing Role: Primary buck converter providing regulated logic rail with high efficiency and thermal resilience under variable load and ambient temperature. Use Value: Delivers 3 A at >86% efficiency across 8–40 V input, eliminating need for heatsinks in convection-cooled enclosures while maintaining ±2% output accuracy. |
Use Scenario: Stepping down 36 V lithium-ion pack voltage to 3.3 V for charging management MCU and communication peripherals. IC Role / Device Role / Timing Role: High-efficiency preregulator preceding linear LDOs or USB-PD controllers - reduces heat generation and extends battery runtime. Use Value: Enables >90% system efficiency at partial loads via 50 µA shutdown mode and maintains regulation during deep discharge (down to 8 V input). |
| Communications Equipment | Radios & RF Front-Ends |
|
Use Scenario: Generating clean 3.3 V supply for Ethernet PHYs and baseband processors in small-cell base stations. IC Role / Device Role / Timing Role: Synchronized buck regulator locked to system clock to fix ripple frequency and simplify EMI filter design. Use Value: External SYNC pin allows alignment to 300 kHz master clock, enabling predictable noise spectrum and meeting EN 55032 Class B conducted emissions limits. |
Use Scenario: Powering low-noise amplifiers (LNAs) and mixers in handheld transceivers where supply ripple directly impacts signal-to-noise ratio. IC Role / Device Role / Timing Role: Low-ripple, thermally stable DC-DC source with minimized switching noise injection into sensitive analog RF sections. Use Value: Fixed 3.3 V output eliminates resistor-divider drift; TO-263 thermal pad ensures stable junction temperature during burst transmit cycles. |
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/NOPB | Same architecture but in SOIC-8 package (no thermal pad); lower max current (2.5 A); RDS(ON) = 0.22 Ω. | Suitable for lower-power, cost-sensitive designs with less stringent thermal requirements and no need for PCB copper area optimization. | Select when board space is limited but thermal load is moderate; avoid for 3 A continuous operation without forced air. |
| TPS54331DR | 3 A synchronous buck with integrated high/low-side FETs; 2.95–28 V input; 570 kHz fixed frequency; no SYNC pin. | Offers higher efficiency at light loads due to synchronous rectification; lacks external sync capability and fixed 3.3 V option (requires FB divider). | Choose for improved light-load efficiency and smaller inductors; use only if SYNC functionality is not required and FB resistor tolerance is acceptable. |
Compared with LM2671MX-3.3/NOPB, the LM2670SX-3.3/NOPB delivers higher current capability and superior thermal performance via its TO-263 thermal pad; compared with TPS54331DR, it trades synchronous rectification for external sync flexibility and fixed-output simplicity - making it preferable for noise-sensitive, multi-rail, or thermally constrained industrial applications.
Availability
LM2670SX-3.3/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charger pre-regulators, communications equipment, and RF front-end power systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2670SX-3.3/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 expertise in high-reliability power conversion ICs.
The LM2670 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for ease-of-use, high-efficiency, and robustness in non-isolated DC-DC buck applications across industrial, communications, and automotive markets.
FAQ
What is the maximum input voltage rating for the LM2670SX-3.3/NOPB?
The LM2670SX-3.3/NOPB 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 safe operating area limits and may trigger internal protection circuits. Always maintain input transient suppression within this envelope for reliable long-term operation of the LM2670SX-3.3/NOPB.
Does the LM2670SX-3.3/NOPB require external feedback resistors?
No - the LM2670SX-3.3/NOPB is a fixed-output variant with internal feedback divider set to 3.3 V. Pin 6 (FB) is internally connected to the reference and must be shorted directly to the output capacitor terminal. Adding external resistors will disrupt regulation and is not supported for this part number.
Can the LM2670SX-3.3/NOPB be synchronized to an external clock?
Yes - the LM2670SX-3.3/NOPB supports external synchronization via Pin 5 (SYNC), accepting TTL- or CMOS-compatible clocks from 280 kHz to 400 kHz. This feature allows precise control of switching frequency for EMI reduction and spectral alignment, and is fully functional on the LM2670SX-3.3/NOPB without modification.
What thermal performance can be expected from the LM2670SX-3.3/NOPB in TO-263 package?
When mounted on a PCB with 0.4896 in² (3.6× package area) of 1 oz copper connected to the thermal pad, the LM2670SX-3.3/NOPB achieves RθJA = 35°C/W. With proper heatsinking, it sustains 3 A continuous output at ambient temperatures up to 85°C without derating - verified per TI's thermal characterization data for the KTW package.
Is the LM2670SX-3.3/NOPB RoHS-compliant and lead-free?
Yes - the LM2670SX-3.3/NOPB carries the /NOPB suffix, indicating lead-free (Pb-free) packaging and full compliance with RoHS Directive 2011/65/EU. The TO-263-7 package uses matte tin lead finish and meets JEDEC J-STD-020 moisture sensitivity level 3 (MSL-3) requirements.
LM2670SX-3.3/NOPB 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:
- Active
- 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/NOPB FAQ
1.How can I place an order for LM2670SX-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2670SX-3.3/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 LM2670SX-3.3/NOPB reliable?
The price and inventory of LM2670SX-3.3/NOPB 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/NOPB is usually 5 days.
3.What payment methods are accepted for LM2670SX-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2670SX-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2670SX-3.3/NOPB?
LM2670SX-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2670SX-3.3/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 LM2670SX-3.3/NOPB?
For technical support, including LM2670SX-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2670SX-3.3/NOPB requirements.
6.How does Aetrix verify that LM2670SX-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2670SX-3.3/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 LM2670SX-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM2670SX-3.3/NOPB?
All LM2670SX-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2670SX-3.3/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 LM2670SX-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM2670SX-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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