Texas Instruments LM2670SX-12/NOPB

Overview

LM2670SX-12/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC converter IC delivering up to 3A output current with fixed 12V output, 8V–40V input range, 260kHz internal oscillator, ±2% output voltage tolerance, and 94% peak efficiency at 24V_IN/3A. It integrates a 150mΩ DMOS high-side switch and supports external clock synchronization for EMI-sensitive communications and radio power supplies.

For engineers reviewing the LM2670SX-12/NOPB datasheet, LM2670SX-12/NOPB pinout, LM2670SX-12/NOPB application, or LM2670SX-12/NOPB equivalent, key selection criteria include its 12V fixed output, TO-263-7 (KTW) thermal performance, SYNC pin frequency control (280–400kHz), ON/OFF enable logic, and compatibility with standard off-the-shelf inductors and Schottky diodes in high-efficiency preregulator designs.

Technical Context

The LM2670SX-12/NOPB implements a voltage-mode PWM buck regulator with an integrated 150mΩ DMOS high-side switch and internal 260kHz oscillator. Its feedback loop uses a two-stage high-gain amplifier referenced to a 1.21V internal bandgap, enabling precise 12V regulation across –40°C to 125°C junction temperature.

It supports both autonomous operation (via internal oscillator) and externally synchronized switching (280–400kHz), where SYNC input overrides internal timing to fix ripple frequency-critical for consistent filtering in RF systems. Shutdown mode reduces quiescent current to 50µA via the ON/OFF pin, while built-in thermal shutdown and current limiting protect against overload and overtemperature conditions.

Key Specifications

Pinout & Package

LM2670SX-12/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad, measuring 10.1mm × 15.24mm. The thermal pad must be soldered to a PCB copper area for optimal thermal performance (R_θJA = 35°C/W with 0.4896 in² copper).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with LM2670SX-12/NOPB, LM2671MX-12/NOPB trades 3A capability for cost and size reduction, while TPS5430DDAR offers synchronous rectification and adjustability at the expense of EMI control and thermal robustness in high-ambient environments.

Availability

LM2670SX-12/NOPB is available at Aetrix Electronics and suitable for industrial PLC power supplies, RF amplifier bias rails, battery charger preregulators, and telecom intermediate bus applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM2670SX-12/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® family - designed specifically for ease-of-use in non-isolated DC-DC buck applications where fast time-to-market, minimal external components, and proven thermal performance are critical.

FAQ

What is the maximum input voltage rating for the LM2670SX-12/NOPB?

The LM2670SX-12/NOPB has an absolute maximum input voltage rating of 45V, but its recommended operating input range is strictly 8V to 40V. Operation above 40V risks exceeding safe operating area limits and may trigger internal protection or cause premature failure. Always maintain input transient suppression within this window for reliable long-term use of the LM2670SX-12/NOPB.

Does the LM2670SX-12/NOPB require external feedback resistors?

No, the LM2670SX-12/NOPB does not require external feedback resistors because it is a fixed 12V output variant. Its internal resistor divider sets the output precisely to 12V with ±2% tolerance across temperature and load. The FB pin is internally connected and should be tied directly to the output capacitor - no external components are needed, simplifying layout and improving reliability of the LM2670SX-12/NOPB.

Can the LM2670SX-12/NOPB be synchronized to an external clock?

Yes, the LM2670SX-12/NOPB supports external synchronization via its SYNC pin (Pin 5). An external TTL- or CMOS-compatible clock signal between 280kHz and 400kHz can override the internal 260kHz oscillator. This feature enables precise control of switching frequency for EMI compliance and spectral positioning - a key differentiator of the LM2670SX-12/NOPB in radio and communications applications.

What thermal performance can be expected from the LM2670SX-12/NOPB in TO-263 package?

In its KTW (TO-263-7) package with proper PCB copper area (0.4896 in²), the LM2670SX-12/NOPB achieves a junction-to-ambient thermal resistance (R_θJA) of 35°C/W. At 3A output and 24V input, typical power dissipation is ~1.8W, resulting in ~63°C junction rise above ambient - well within its –40°C to 125°C operating range. Thermal pad soldering is mandatory for this performance level in the LM2670SX-12/NOPB.

Is the LM2670SX-12/NOPB RoHS-compliant and lead-free?

Yes, the LM2670SX-12/NOPB is RoHS-compliant and lead-free, as indicated by the "/NOPB" suffix in its part number (NOPB = No Lead, Pb-Free). It meets JEDEC J-STD-020 moisture sensitivity level 3 and is qualified for reflow soldering per IPC/JEDEC J-STD-020. Full compliance documentation, including material declarations and test reports, is available on Texas Instruments' product folder for the LM2670SX-12/NOPB.