Texas Instruments SN74LVC126ADBR

Overview

SN74LVC126ADBR from Texas Instruments is a quadruple 3-state bus buffer gate operating from 1.65 V to 3.6 V, featuring 5.5 V-tolerant inputs, 4.7 ns max propagation delay at 3.3 V, and –40°C to +125°C temperature range. It serves as a level-translating buffer in mixed-voltage digital buses for consumer audio/video and embedded storage interfaces.

For engineers reviewing the SN74LVC126ADBR datasheet, SN74LVC126ADBR pinout, SN74LVC126ADBR application, or SN74LVC126ADBR equivalent, key selection criteria include 3-state output control timing (ten/tdis), input overvoltage tolerance, thermal performance in SSOP-14, and compatibility with 1.8 V/2.5 V/3.3 V logic families in high-density PCB layouts.

Technical Context

The SN74LVC126ADBR implements four independent non-inverting buffers, each with dedicated active-low output-enable (OE) control. Its CMOS design supports bidirectional voltage translation: inputs accept up to 5.5 V regardless of VCC (1.65–3.6 V), enabling reliable interfacing between legacy 5 V systems and modern low-voltage controllers.

Each buffer drives up to 24 mA at 3 V while maintaining rail-to-rail VOH/VOL compliance across temperature. The device uses standard LVC process technology with latch-up immunity >250 mA per JESD17, and requires pulldown biasing on OE pins during power sequencing to guarantee high-impedance startup behavior.

Key Specifications

Pinout & Package

SN74LVC126ADBR is packaged in a 14-pin SSOP (Shrink Small Outline Package) with 6.2 mm × 7.8 mm body size and 0.65 mm lead pitch. The exposed thermal pad is not present in SSOP; thermal management relies on PCB copper pour connected to GND via multiple vias under the package footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus buffer applications.

Compared with SN74LVC126ADBR, SN74LVC125ADBR changes OE polarity without altering timing or drive capability, while 74LVC126PW,118 offers identical function in a physically incompatible package-both require schematic and layout verification before substitution.

Availability

SN74LVC126ADBR is available at Aetrix Electronics and suitable for audio/video receivers, solid-state drive controllers, industrial HMIs, and enterprise tablet designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVC126ADBR 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 connectivity technologies with over 90 years of innovation in high-reliability components.

The SN74LVC126ADBR belongs to TI's LVC logic family, engineered for low-voltage, high-speed digital interfacing in space-constrained consumer and industrial systems where voltage translation and bus isolation are critical.

FAQ

What is the maximum input voltage the SN74LVC126ADBR can tolerate?

The SN74LVC126ADBR accepts input voltages up to 5.5 V regardless of VCC level (1.65–3.6 V), making it suitable for interfacing with 5 V logic in mixed-voltage systems. This overvoltage tolerance is specified across the full operating temperature range (–40°C to +125°C) and does not require external clamping diodes. The SN74LVC126ADBR maintains this rating even when outputs are disabled.

Does the SN74LVC126ADBR require external pull-down resistors on its OE pins?

Yes-the SN74LVC126ADBR requires pulldown resistors on all four OE pins (pins 1, 4, 10, 13) to ensure outputs enter high-impedance state during power-up and power-down. TI specifies that the minimum resistor value depends on the driver's current-sourcing capability; typical values range from 1 kΩ to 10 kΩ. Without this bias, undefined OE states may cause bus contention or excessive current draw. This requirement applies to every instance of SN74LVC126ADBR in the design.

Can the SN74LVC126ADBR drive a 50 pF load at 100 MHz?

The SN74LVC126ADBR is characterized for 50 pF loads in switching tests (e.g., tpd, ten, tdis), with 4.7 ns max propagation delay at 3.3 V. While it supports signal frequencies up to ~100 MHz in controlled impedance environments, sustained 100 MHz operation demands careful attention to PCB layout: minimize trace length, use series termination if needed, and ensure solid ground return paths. The SN74LVC126ADBR's ±24 mA drive strength helps maintain edge integrity into such loads, but system-level signal integrity validation remains essential.

What is the thermal resistance (RθJA) of the SN74LVC126ADBR in its SSOP package?

The SN74LVC126ADBR in SSOP-14 (DB package) has a junction-to-ambient thermal resistance (RθJA) of 112.2°C/W, measured per JESD51-7. This value assumes standard JEDEC high-K test board conditions. In real-world PCBs with 2 oz copper and 4 thermal vias under the package, actual RθJA typically improves to ~70–85°C/W. Derating begins above +60°C ambient, with linear reduction of 5.5 mW/K-critical for SN74LVC126ADBR thermal design in enclosed industrial enclosures.

How does the SN74LVC126ADBR differ from the SN74LVC126ADR?

The SN74LVC126ADBR and SN74LVC126ADR share identical electrical specifications, pinout, and logic function but differ in package and packaging format: SN74LVC126ADBR uses SSOP-14 (6.2 mm × 7.8 mm) in tape-and-reel (2000 pcs), while SN74LVC126ADR uses SOIC-14 (8.65 mm × 6 mm) in tape-and-reel (2500 pcs). Mechanical incompatibility prevents direct PCB substitution. Both are rated for –40°C to +125°C and carry identical RoHS/NIPDAU finishes and MSL Level-1 ratings. The SN74LVC126ADBR is preferred where board space is constrained.