Texas Instruments SN74LVTH126DRG4

Overview

SN74LVTH126DRG4 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 delivers 64 mA sink current per output, supports hot insertion via I_off and power-up 3-state, and operates down to 2.7 V for battery-powered systems.

For engineers reviewing the SN74LVTH126DRG4 datasheet, SN74LVTH126DRG4 pinout, SN74LVTH126DRG4 application, or SN74LVTH126DRG4 equivalent, key selection criteria include mixed-mode voltage tolerance (5-V input/3.3-V V_CC), bus-hold elimination of external resistors, high-impedance control during power sequencing, and SOIC-14 package compatibility with industrial logic interface designs.

Technical Context

The SN74LVTH126DRG4 implements four independent noninverting buffers, each with dedicated 3-state output-enable (OE) control. Its bus-hold circuitry actively maintains valid logic states on undriven data inputs without external pullup/pulldown resistors.

It features I_off protection that disables outputs when V_CC = 0 V, preventing backflow current during hot insertion, and power-up 3-state logic that forces outputs into high-impedance during V_CC ramp-up from 0 V to 1.5 V - critical for system-level power sequencing integrity.

Key Specifications

Pinout & Package

SN74LVTH126DRG4 is housed in a 14-pin SOIC (D) package, 8.75 mm × 3.91 mm footprint, 1.75 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 3-state buffer applications.

Compared with SN74LVC126A and 74ALVC126, SN74LVTH126DRG4 uniquely combines 5-V-tolerant inputs, bus-hold, I_off, and 64-mA drive - making it the sole option for robust, resistor-free, mixed-voltage hot-plug interfaces in industrial and automotive control systems.

Availability

SN74LVTH126DRG4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, embedded controller expansion buses, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74LVTH126DRG4 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 innovation in industrial, automotive, and communications markets.

The SN74LVTH126DRG4 belongs to TI's LVTH logic family, engineered specifically for mixed-voltage system integration - enabling seamless interoperability between legacy 5-V TTL infrastructure and modern 3.3-V digital subsystems.

FAQ

What is the minimum V_CC required for reliable operation of the SN74LVTH126DRG4?

The SN74LVTH126DRG4 is fully specified from 2.7 V to 3.6 V. Below 2.7 V, parameters such as t_PLH, V_OH, and I_OL degrade outside guaranteed limits; operation at 2.5 V may yield marginal timing or drive capability. For battery-powered designs, ensure V_CC remains ≥2.7 V across the full discharge curve to maintain SN74LVTH126DRG4 functionality.

Does the SN74LVTH126DRG4 require external pullup resistors on its data inputs?

No. The SN74LVTH126DRG4 integrates active bus-hold circuitry on all data inputs (pins 2, 5, 9, 12), which maintains the last valid logic state without external components. Using pullup or pulldown resistors with SN74LVTH126DRG4 is explicitly discouraged in the datasheet, as they conflict with internal bus-hold current and may cause excessive power draw or logic instability.

Can the SN74LVTH126DRG4 safely interface a 5-V microcontroller with a 3.3-V FPGA?

Yes - the SN74LVTH126DRG4 accepts 5-V TTL inputs while operating from a 3.3-V V_CC, making it ideal for driving 3.3-V FPGA I/O banks from 5-V control logic. Its V_IH = 2.0 V min and V_IL = 0.8 V max ensure robust recognition of 5-V logic levels, and its 3.3-V-compatible outputs meet FPGA input thresholds without level-shifting circuitry.

What thermal considerations apply to the SN74LVTH126DRG4 in continuous 64-mA output operation?

In sustained 64-mA sink operation per output, the SN74LVTH126DRG4's SOIC package exhibits θ_JA = 86°C/W. At 3.3 V and 4 outputs driving 64 mA each, total power dissipation reaches ~180 mW, raising junction temperature by ~15°C above ambient. No heatsink is required below 70°C ambient, but ensure ≥1 cm² copper pour under pin 7 (GND) for optimal thermal conduction.

Is the SN74LVTH126DRG4 pin-compatible with earlier SN74LVTH126 variants like SN74LVTH126DR?

Yes - SN74LVTH126DRG4 shares identical pinout, electrical specifications, and SOIC-14 package dimensions with SN74LVTH126DR and SN74LVTH126D. The "G4" suffix denotes green (lead-free) packaging per TI's environmental compliance program, with no functional or mechanical differences affecting PCB layout or schematic design for SN74LVTH126DRG4 integration.