Texas Instruments SN74LVTH126DBR

Overview

SN74LVTH126DBR from Texas Instruments is a 3.3-V quad buffer with 3-state outputs and bus-hold inputs, designed for mixed-mode interfacing between 3.3-V logic and 5-V TTL systems. It supports hot insertion via Ioff and power-up 3-state, operates down to 2.7 V, delivers 64 mA sink current per output, and features <0.8 V typical output ground bounce at VCC = 3.3 V - enabling robust signal integrity in industrial backplane and data acquisition interfaces.

For engineers reviewing the SN74LVTH126DBR datasheet, SN74LVTH126DBR pinout, SN74LVTH126DBR application, or SN74LVTH126DBR equivalent, key selection criteria include its 14-pin SSOP (DB) package, bus-hold input capability eliminating external resistors, guaranteed hot-swap support, and compatibility with both 3.3-V supply and 5-V input/output voltage levels in mixed-voltage system interconnects.

Technical Context

This device implements four independent noninverting buffers, each with an active-high output-enable (OE) control line. Each output enters high-impedance state when its OE is low, and all outputs are disabled during power-up/power-down when VCC is below 1.5 V or via pulldown on OE.

Bus-hold circuitry actively maintains valid logic states on undriven inputs without external components, while Ioff protection prevents current backflow when powered down. The architecture meets JESD 78 Class II latch-up immunity (>100 mA) and exceeds JESD 22 ESD ratings: 2000-V HBM, 200-V MM, and 1000-V CDM.

Key Specifications

Pinout & Package

SN74LVTH126DBR uses a 14-pin Shrink Small-Outline Package (SSOP-DB), 5.3 mm × 6.2 mm body, 0.65 mm lead pitch, 2.0 mm max height, JEDEC MO-150 compliant. Pin 1 index located at top-left corner with beveled edge marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC126A DBR and SN74ALVCH126 DBR, SN74LVTH126DBR uniquely combines bus-hold, Ioff, and 5-V-tolerant inputs in a single 3.3-V-buffer solution - making it the only option that simultaneously eliminates external resistors, enables live insertion, and maintains interoperability with legacy 5-V logic without additional circuitry.

Availability

SN74LVTH126DBR is available at Aetrix Electronics and suitable for industrial backplane interfaces, automated test equipment, medical data acquisition systems, and ruggedized communication modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVTH126DBR 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 logic solutions with over 50 years of industrial-grade product development.

The SN74LVTH126DBR belongs to TI's LVTH logic family, engineered specifically for mixed-voltage system interfacing where 3.3-V logic must reliably communicate with legacy 5-V TTL infrastructure under demanding environmental conditions.

FAQ

What is the operating temperature range for SN74LVTH126DBR?

The SN74LVTH126DBR is rated for operation from −40°C to +85°C, meeting industrial-grade environmental requirements. This range is validated per the recommended operating conditions table in the official datasheet SCBS746B, and applies specifically to the SSOP-DB package variant. Thermal performance is characterized with θJA = 96°C/W, supporting reliable operation in enclosed enclosures with natural convection cooling.

Does SN74LVTH126DBR require external pullup resistors on its inputs?

No, SN74LVTH126DBR does not require external pullup or pulldown resistors due to its integrated bus-hold circuitry. Each data input actively maintains its last-valid logic state when undriven, with ±75 µA hold current specified at VCC = 3 V. Using external resistors with SN74LVTH126DBR is explicitly discouraged in the datasheet as it may interfere with bus-hold functionality and increase power consumption.

Can SN74LVTH126DBR safely interface a 3.3-V microcontroller with a 5-V peripheral?

Yes, SN74LVTH126DBR is expressly designed for this mixed-mode interface. Its inputs tolerate up to 5.5 V regardless of VCC level, and its outputs swing rail-to-rail within the 3.3-V domain while driving 5-V TTL loads. The device meets 5-V TTL input thresholds (VIH = 2.0 V min) and provides sufficient output current (64 mA sink) to meet TTL fan-out requirements without additional level-shifting circuitry.

Is SN74LVTH126DBR suitable for hot-plug applications?

Yes, SN74LVTH126DBR supports hot insertion through two complementary features: Ioff circuitry disables outputs when VCC = 0 V to prevent damaging current backflow, and power-up 3-state ensures outputs remain high-impedance during power ramp-up or ramp-down. These capabilities are fully characterized and guaranteed per the datasheet's "hot-insertion applications" section and align with JESD78 latch-up and JESD22 ESD specifications.

What is the maximum output current capability of SN74LVTH126DBR?

SN74LVTH126DBR delivers up to 64 mA sink current (IOL) per output at VCC = 3.3 V and 0.55 V max VOL, and supports 32 mA source current (IOH) with 2.0 V min VOH. These values are specified under recommended operating conditions and enable direct driving of standard TTL loads, LED indicators, and moderate-capacitance buses without external amplification.