Texas Instruments LM2670SDX-5.0/NOPB

Overview

LM2670SDX-5.0/NOPB from Texas Instruments is a monolithic step-down (buck) DC/DC switching regulator IC delivering up to 3 A output current with fixed 5 V output, 8–40 V input range, ±2% output voltage tolerance, and 260 kHz internal oscillator frequency. It integrates a 150 mΩ DMOS high-side switch and supports external synchronization for ripple frequency control in communications and radio equipment.

For engineers reviewing the LM2670SDX-5.0/NOPB datasheet, LM2670SDX-5.0/NOPB pinout, LM2670SDX-5.0/NOPB application, or LM2670SDX-5.0/NOPB equivalent, key selection criteria include its 50 µA standby current in shutdown mode, thermal shutdown and current limiting protection, SYNC pin compatibility with 280–400 kHz external clocks, and TO-263-7 (KTW) package with exposed thermal pad for high-power dissipation.

Technical Context

The LM2670SDX-5.0/NOPB implements a voltage-mode PWM controller with an internal 260 kHz oscillator and supports external clock synchronization via the SYNC pin - enabling precise ripple frequency positioning for EMI-sensitive applications. Its high-side DMOS switch features 150 mΩ typical R_DS(ON), optimized for efficiency up to 88% at 12 V_IN/3 A load.

Operation includes active-mode regulation and shutdown mode controlled by the ON/OFF pin (1.4 V threshold), with built-in thermal shutdown, cycle-by-cycle current limiting (3.8–5.25 A), and feedback sensing referenced to a stable 1.21 V internal reference. The FB pin connects directly to the output for fixed 5 V versions, eliminating external resistor dividers.

Key Specifications

Pinout & Package

LM2670SDX-5.0/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with an exposed thermal pad (DAP) that must be soldered to PCB ground 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 LM2670SDX-5.0/NOPB, LM2671SD-5.0 sacrifices synchronization capability for lower cost and simpler layout, while TPS54302DDCR trades fixed-output convenience for greater input flexibility and synchronous rectification - making LM2670SDX-5.0/NOPB optimal where EMI-controlled 5 V generation from 8–40 V is required.

Availability

LM2670SDX-5.0/NOPB is available at Aetrix Electronics and suitable for industrial power preregulation, communications equipment supply, battery charger auxiliary rails, and test & measurement instrumentation requiring stable component supply and long-term manufacturability.

Supply support for LM2670SDX-5.0/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 in non-isolated DC/DC buck applications where fast time-to-market, minimal external components, and robust protection features are critical.

FAQ

What is the maximum input voltage rating for the LM2670SDX-5.0/NOPB?

The LM2670SDX-5.0/NOPB has an absolute maximum input voltage rating of 45 V, but its recommended operating input voltage range is 8 V to 40 V. Operation above 40 V risks exceeding safe operating area limits and may trigger internal protection circuits or cause permanent damage. Designers should maintain input transients below 40 V under all conditions, including load dump or inductive kickback scenarios.

Does the LM2670SDX-5.0/NOPB require external feedback resistors for 5 V output?

No - the LM2670SDX-5.0/NOPB is a fixed 5 V output variant. Its internal feedback divider is factory-trimmed to deliver 5.0 V ±2% over temperature and load. Pin 6 (FB) must be connected directly to the output capacitor; no external resistors are needed, reducing component count and layout sensitivity compared to adjustable versions.

How does the SYNC pin function on the LM2670SDX-5.0/NOPB?

The SYNC pin (Pin 5) accepts an external TTL/CMOS clock signal between 280 kHz and 400 kHz to override the internal 260 kHz oscillator. When driven, it forces the switching frequency to match the external clock, enabling precise ripple frequency control. Note: current limit foldback is disabled during SYNC operation, so short-circuit protection relies solely on cycle-by-cycle current limiting.

What thermal management is required for the LM2670SDX-5.0/NOPB in TO-263 package?

The LM2670SDX-5.0/NOPB in KTW (TO-263-7) package requires soldering its exposed thermal pad (DAP) to a minimum 0.4896 in² (3.6× package area) copper pour connected to system ground. With this layout, junction-to-ambient thermal resistance is 35°C/W. Without adequate copper, thermal impedance rises sharply - risking thermal shutdown at full 3 A load above 60°C ambient.

Can the LM2670SDX-5.0/NOPB be used in battery-powered systems with low standby power requirements?

Yes - the LM2670SDX-5.0/NOPB draws only 50 µA quiescent current when the ON/OFF pin is pulled low, making it suitable for battery-backed systems. Its shutdown mode retains full protection (thermal, current limit) while minimizing drain. For ultra-low-power wake-up, the ON/OFF pin can be driven by a microcontroller GPIO or external logic with <0.8 V threshold for reliable turn-off.