Texas Instruments LM2676SX-5.0/NOPB

Overview

LM2676SX-5.0/NOPB from Texas Instruments is a monolithic step-down (buck) switching regulator IC delivering up to 3A output current with fixed 5.0V output, 8V–40V input range, 260kHz fixed-frequency operation, and ±2% output voltage tolerance over full line/load/temperature. It integrates a 150mΩ DMOS high-side switch and supports ON/OFF control for low-power standby mode in industrial power supplies.

For engineers reviewing the LM2676SX-5.0/NOPB datasheet, LM2676SX-5.0/NOPB pinout, LM2676SX-5.0/NOPB application, or LM2676SX-5.0/NOPB equivalent, key selection criteria include its 3A continuous load capability, thermal performance in TO-263 (KTW) package, 50µA shutdown quiescent current, and compatibility with standard off-the-shelf inductors and Schottky diodes per TI's SIMPLE SWITCHER® design methodology.

Technical Context

The LM2676SX-5.0/NOPB implements a fixed-frequency PWM buck controller with internal 260kHz oscillator and integrated 150mΩ DMOS high-side switch. Its feedback loop uses a precision 1.21V reference (±1.2% over temperature) and senses output directly at the FB pin-no external divider required for the fixed-5V version.

It operates across –40°C to +125°C junction temperature, features cycle-by-cycle current limiting (4.5A typ), thermal shutdown, and enables system-level power sequencing via the ON/OFF pin with 1.4V threshold and 20µA input bias current.

Key Specifications

Pinout & Package

LM2676SX-5.0/NOPB is supplied in the KTW (TO-263-7) thermally enhanced surface-mount package (10.1mm × 15.24mm), featuring an exposed thermal pad electrically connected to GND for optimal PCB heat transfer.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2676SX-5.0/NOPB, LM2675MX-5.0/NOPB offers identical functionality at half the current capacity, while LMR16006XDDAR trades current and pin compatibility for wider input range and higher frequency-neither serves as a drop-in replacement, but both address adjacent design constraints in cost, size, or voltage range.

Availability

LM2676SX-5.0/NOPB is available at Aetrix Electronics and suitable for communication modules, electricity meters, and motor drive auxiliary supplies requiring stable component supply, long-lifecycle support, and proven thermal reliability in TO-263 packaging.

Supply support for LM2676SX-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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies with broad industrial and automotive reach.

The LM2676 series belongs to TI's SIMPLE SWITCHER® power converter family, designed specifically to simplify high-efficiency DC/DC buck regulator implementation using minimal external components and standardized magnetics.

FAQ

What is the maximum input voltage rating for LM2676SX-5.0/NOPB?

The absolute maximum input voltage for LM2676SX-5.0/NOPB is 45V, but the recommended operating range is 8V to 40V. Exceeding 40V continuously risks violating safe operating area limits of the internal DMOS switch and may trigger overvoltage protection or premature failure. Designers should include input transient suppression if the source can exceed 40V under surge or no-load conditions.

Does LM2676SX-5.0/NOPB require an external feedback resistor divider?

No, LM2676SX-5.0/NOPB does not require an external feedback resistor divider. As a fixed 5.0V output variant, it internally sets the feedback reference and expects the FB pin to be connected directly to the output capacitor. Adding external resistors would disrupt regulation and cause output voltage error-TI's datasheet confirms direct connection for all fixed-output versions including LM2676SX-5.0/NOPB.

What thermal performance can be expected from LM2676SX-5.0/NOPB in its KTW package?

In the KTW (TO-263-7) package with 0.136 in² copper area, LM2676SX-5.0/NOPB has a junction-to-ambient thermal resistance (θ_JA) of 56°C/W. At 3A output and 12V input, typical power dissipation is ~1.3W, resulting in ~73°C junction rise above ambient-well within the –40°C to 125°C operating range. For higher ambient or sustained loads, adding thermal vias to inner ground layers further reduces θ_JA to ~35°C/W.

Can LM2676SX-5.0/NOPB be synchronized to an external clock?

No, LM2676SX-5.0/NOPB cannot be synchronized to an external clock. It uses an internal fixed-frequency 260kHz oscillator with ±11% tolerance and no synchronization pin or frequency adjustment capability. For designs requiring clock synchronization (e.g., multi-rail systems), consider TI's newer LM5115 or TPS546D24 families, which provide SYNC input functionality absent in the LM2676SX-5.0/NOPB.

What is the purpose of the CB pin on LM2676SX-5.0/NOPB?

Pin 3 (CB) on LM2676SX-5.0/NOPB is the bootstrap capacitor terminal for the high-side gate driver. It must be connected via a 100nF ceramic capacitor to the SW pin (Pin 1) to generate a voltage ~V_IN + 10V across the gate-source of the internal DMOS switch-ensuring full enhancement and minimizing R_DS(ON). Omitting or undersizing this capacitor causes weak gate drive, increased switching losses, and potential thermal runaway under load.