Texas Instruments SN74LVTH126PW

Overview

SN74LVTH126PW from Texas Instruments is a quad 3-state noninverting buffer with bus-hold circuitry, designed for 3.3-V V_CC operation while supporting 5-V TTL-level inputs and outputs. It features independent output-enable control per channel, I_off protection for hot insertion, and operates down to 2.7 V-enabling use in mixed-voltage industrial control backplanes and legacy 5-V system interfacing.

For engineers reviewing the SN74LVTH126PW datasheet, SN74LVTH126PW pinout, SN74LVTH126PW application, or SN74LVTH126PW equivalent, key selection criteria include its 3.3-V supply compatibility with 5-V signal tolerance, bus-hold elimination of external pull resistors, guaranteed 2.7–3.6-V operating range, and TSSOP-14 package thermal performance (θ_JA = 113°C/W).

Technical Context

This device implements four independent noninverting buffers, each with active-high output-enable (OE) control and integrated bus-hold on all data inputs. The bus-hold circuit maintains valid logic states on undriven inputs without external components, drawing ±500 µA max dynamic current at V_CC = 3.6 V.

It supports hot insertion via dual protection mechanisms: I_off disables outputs when V_CC = 0 V (blocking reverse current), and power-up 3-state forces high-impedance during V_CC ramp (0–1.5 V), preventing bus contention. Output ground bounce (V_OLP) is specified <0.8 V at V_CC = 3.3 V, TA = 25°C.

Key Specifications

Pinout & Package

TSSOP-14 package (PW), 5.0 mm × 4.4 mm × 1.2 mm height, JEDEC MO-153 compliant, with exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC126APW and SN74AHCT126PW, the SN74LVTH126PW uniquely combines 5-V input tolerance, bus-hold, I_off, and 3.3-V operation-making it the sole option for robust, low-risk 3.3/5-V bridging in industrial hot-swap environments.

Availability

SN74LVTH126PW is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system upgrades, and hot-swappable module carriers requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for SN74LVTH126PW 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 for industrial, automotive, and communications markets.

The SN74LVTH126PW belongs to TI's LVTH logic family, engineered specifically for mixed-voltage system interfacing-delivering TTL-compatible performance at 3.3-V supply while ensuring interoperability with legacy 5-V infrastructure.

FAQ

What is the minimum V_CC required for functional operation of the SN74LVTH126PW?

The SN74LVTH126PW is fully specified from 2.7 V to 3.6 V. Below 2.7 V, parameters such as output drive strength, propagation delay, and bus-hold current are not guaranteed. At V_CC < 1.5 V, the outputs enter high-impedance regardless of OE state-this is a safety feature, not functional operation. For reliable logic behavior, maintain V_CC ≥ 2.7 V per the recommended operating conditions table in the SN74LVTH126PW datasheet.

Does the SN74LVTH126PW require external pullup or pulldown resistors on its inputs?

No. The SN74LVTH126PW integrates active bus-hold circuitry on all data inputs (pins 2, 5, 11, 14), which maintains the last-valid logic state without external components. TI explicitly warns against using pullup or pulldown resistors with bus-hold enabled, as they conflict with the internal hold current and may cause excessive power draw or metastability. This feature is confirmed in the SN74LVTH126PW functional description and electrical characteristics tables.

Can the SN74LVTH126PW safely interface a 3.3-V microcontroller GPIO to a 5-V peripheral without additional level-shifting components?

Yes. The SN74LVTH126PW accepts 5-V TTL-level inputs (VIH = 2 V min, VI up to 5.5 V) while operating from a 3.3-V V_CC, and its outputs swing rail-to-rail (VOH ≈ V_CC − 0.2 V, VOL ≈ 0.5 V) with 64-mA sink capability-sufficient to drive standard 5-V TTL loads. This dual-voltage capability is a core specification of the SN74LVTH126PW and eliminates the need for discrete level shifters in such interfaces.

What thermal derating applies to the SN74LVTH126PW in a 2-layer PCB with standard copper pour?

The SN74LVTH126PW has a junction-to-ambient thermal resistance (θ_JA) of 113°C/W in its TSSOP-14 (PW) package. On a typical 2-layer PCB with 1-oz copper and moderate ground/power pour, continuous power dissipation should be limited to ≤300 mW to keep junction temperature ≤105°C at 85°C ambient. This corresponds to average I_CC ≤ 90 mA (at 3.3 V), well within the 4.5–7 mA typical supply current range specified for the SN74LVTH126PW under static conditions.

Is the SN74LVTH126PW pin-compatible with other packages in the 'LVTH126 family, such as SN74LVTH126DBR or SN74LVTH126PWR?

Yes-the SN74LVTH126PW shares identical pinout and logic function with all 'LVTH126 variants including SN74LVTH126DBR (SSOP), SN74LVTH126PWR (TSSOP tape-and-reel), and SN74LVTH126D (SOIC). All use the same 14-pin topology: OE/A/Y per channel plus V_CC and GND. However, mechanical dimensions, thermal performance (θ_JA differs by package), and packaging format (tube vs. tape-and-reel) vary-so PCB footprint and assembly process must match the specific package variant selected, including the SN74LVTH126PW.