Texas Instruments LM2676SD-3.3/NOPB

Overview

LM2676SD-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 fixed-frequency operation, and ±2% output voltage tolerance over full line/load/temperature. It integrates a 150 mΩ DMOS high-side switch and supports ON/OFF control for low-power standby mode.

For engineers reviewing the LM2676SD-3.3/NOPB datasheet, LM2676SD-3.3/NOPB pinout, LM2676SD-3.3/NOPB application, or LM2676SD-3.3/NOPB equivalent, key selection criteria include its 3.3 V fixed output accuracy, thermal shutdown protection, 50 µA standby current, TO-263-7 (KTW) package footprint, and compatibility with standard off-the-shelf inductors and Schottky diodes in industrial power supply designs.

Technical Context

The LM2676SD-3.3/NOPB implements a voltage-mode PWM controller with a fixed 260 kHz oscillator driving an internal DMOS high-side switch. Its feedback loop uses a dedicated FB pin tied directly to the output for fixed-voltage regulation, eliminating external resistor dividers. The device operates in continuous conduction mode (CCM) across its full 100 mA–3 A load range at typical input voltages.

Functional modes include active regulation (ON/OFF ≥ 1.4 V) and shutdown (ON/OFF ≤ 0.8 V), with built-in current limiting (3.6–5.4 A), thermal shutdown, and 50 µA quiescent current in standby. The KTW package features exposed DAP ground connection for enhanced thermal performance in high-current applications.

Key Specifications

Pinout & Package

The LM2676SD-3.3/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad (DAP) connected to Pin 4 (GND). The DAP must be soldered to a PCB copper pour 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 LM2675SD-3.3/NOPB and TPS54332DR, the LM2676SD-3.3/NOPB delivers guaranteed 3 A output with integrated protection and fixed-frequency simplicity, making it optimal for cost-sensitive, thermally constrained industrial buck applications where external diode use is acceptable.

Availability

LM2676SD-3.3/NOPB is available at Aetrix Electronics and suitable for industrial electricity meters, motor drive control boards, and calling button operating panels requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM2676SD-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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies for industrial, automotive, and communications markets.

The LM2676 series belongs to TI's SIMPLE SWITCHER® power converter family, designed specifically for easy-to-implement, high-efficiency DC-DC buck conversion in cost-sensitive industrial equipment where minimal external components and robust thermal performance are critical.

FAQ

What is the maximum input voltage rating for the LM2676SD-3.3/NOPB?

The LM2676SD-3.3/NOPB has an absolute maximum input voltage rating of 45 V, but its recommended operating input range is 8 V to 40 V. Operation above 40 V risks exceeding safe junction temperature limits and may trigger internal protection circuits. For reliable long-term use in industrial environments, maintain VIN ≤ 40 V with appropriate transient suppression on the input rail.

Does the LM2676SD-3.3/NOPB require external feedback resistors?

No, the LM2676SD-3.3/NOPB does not require external feedback resistors. As a fixed-output variant, it contains internal precision resistors that set the 3.3 V regulation point. The FB pin (Pin 6) must be connected directly to the output capacitor's positive terminal - no external divider network is needed, simplifying layout and improving stability.

What thermal performance can be expected from the LM2676SD-3.3/NOPB in a standard PCB layout?

In a standard 4-layer PCB with 0.4896 in² (3.6× package area) of 1 oz copper connected to the KTW package's DAP, the LM2676SD-3.3/NOPB achieves R_θJA = 35°C/W. At 3 A output and 12 V input, this yields ~35°C rise above ambient - well within the –40°C to 125°C junction range. Adequate copper area and thermal vias are essential to maintain this performance.

Can the LM2676SD-3.3/NOPB be used in discontinuous conduction mode (DCM)?

Yes, the LM2676SD-3.3/NOPB operates reliably in both continuous and discontinuous conduction modes. At light loads (< 500 mA), it naturally transitions to DCM, reducing switching losses and maintaining regulation. The 260 kHz fixed frequency and internal compensation ensure stable loop behavior across the full 100 mA–3 A load range without external tuning.

Is the LM2676SD-3.3/NOPB RoHS-compliant and lead-free?

Yes, the LM2676SD-3.3/NOPB is RoHS-compliant and lead-free. The "/NOPB" suffix explicitly denotes lead-free packaging per JEDEC J-STD-609. It meets IPC/JEDEC J-STD-020 moisture sensitivity level 3 (MSL-3) and is qualified for standard Pb-free reflow profiles with peak temperatures up to 260°C.