Texas Instruments SN74LVT125PW

Overview

SN74LVT125PW from Texas Instruments is a quad 3-state noninverting buffer designed for mixed-voltage system interfacing, supporting 5-V TTL inputs/outputs with 3.3-V V_CC, operating down to 2.7 V, and featuring bus-hold inputs and I_off protection. It enables level translation between legacy 5-V logic and modern 3.3-V buses in industrial control backplanes and FPGA I/O expansion.

For engineers reviewing the SN74LVT125PW datasheet, SN74LVT125PW pinout, SN74LVT125PW application, or SN74LVT125PW equivalent, key selection criteria include its 3.3-V supply compatibility with 5-V tolerant inputs, 2.7–3.6-V operating range, bus-hold functionality eliminating external pullups, I_off support for partial power-down, and TSSOP-14 package thermal performance (θ_JA = 113°C/W).

Technical Context

The SN74LVT125PW implements four independent noninverting buffers, each with active-low 3-state output enable (OE) control and integrated bus-hold circuitry on all A inputs. Its I_off specification ensures outputs are high-impedance and leakage-limited (<±100 µA) when V_CC = 0 V, enabling safe hot-insertion in powered-backplane systems.

It supports mixed-mode signal operation via 5-V-tolerant inputs (VI up to 7 V) and outputs capable of driving 5-V loads while powered from 3.3-V V_CC. Propagation delays are tightly specified: t_PLH/t_PHL ≤ 4.9 ns at V_CC = 2.7 V, CL = 50 pF, ensuring timing integrity in high-speed digital interconnects.

Key Specifications

Pinout & Package

TSSOP-14 (PW) package: 4.4 mm × 5.0 mm body, 0.65 mm lead pitch, 1.2 mm max height, exposed pad not present, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVTH125PW and SN74ALVC125PW, the SN74LVT125PW uniquely combines 5-V input tolerance, bus-hold, and I_off in a single TSSOP-14 package - making it the only option for robust mixed-voltage backplane interfaces requiring zero external components and safe partial power-down.

Availability

SN74LVT125PW is available at Aetrix Electronics and suitable for industrial backplane interfaces, FPGA I/O expansion, test equipment signal conditioning, and communications module data bus applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74LVT125PW 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 decades of expertise in high-reliability interface ICs for industrial and automotive markets.

The SN74LVT125PW belongs to TI's LVT (Low-Voltage BiCMOS Technology) logic family, engineered specifically for mixed-voltage system bridging - delivering 5-V signal compatibility with 3.3-V power efficiency in space-constrained industrial control and instrumentation designs.

FAQ

What is the minimum V_CC required for guaranteed operation of the SN74LVT125PW?

The SN74LVT125PW is fully specified from 2.7 V to 3.6 V per its recommended operating conditions. At V_CC = 2.7 V, it maintains t_PLH/t_PHL ≤ 4.9 ns and I_OL = 24 mA, supporting unregulated battery operation down to 2.7 V without functional degradation. Operation below 2.7 V is not characterized and may result in undefined output states or increased propagation delay.

Does the SN74LVT125PW require external pullup resistors on its A inputs?

No. The SN74LVT125PW integrates active bus-hold circuitry on all four A inputs, which maintains a valid logic state (±75 µA hold current) when inputs are unused or undriven. TI explicitly advises against using external pullup or pulldown resistors with this device, as they conflict with bus-hold operation and may cause excessive current draw or logic contention.

Can the SN74LVT125PW safely interface with 5-V microcontrollers while powered from 3.3 V?

Yes. The SN74LVT125PW accepts input voltages up to 7 V (including 5-V TTL levels) while operating from V_CC = 3.3 V, and its outputs swing rail-to-rail (VOH ≈ V_CC, VOL < 0.55 V) - enabling direct connection to 5-V inputs with appropriate current limiting if driving 5-V loads. Its 5-V-tolerant inputs eliminate level-shifter requirements for receiving signals from 5-V MCUs.

What is the purpose of the I_off specification in the SN74LVT125PW datasheet?

The I_off specification (±100 µA max at V_CC = 0 V) ensures that when the SN74LVT125PW is unpowered but connected to live 5-V buses, its outputs remain in high-impedance state with negligible leakage current. This prevents damaging backflow through the device, enabling safe hot-insertion into powered backplanes - a critical requirement for modular industrial and telecom systems.

How does the SN74LVT125PW handle ground bounce during high-speed switching?

The SN74LVT125PW is characterized for low ground bounce: typical V_OLP < 0.8 V at V_CC = 3.3 V, TA = 25°C. This is achieved through optimized output stage design and strict layout guidance (e.g., low-inductance GND connection). Designers must follow TI's PCB recommendations - including dedicated ground plane, short GND traces, and local 0.1 µF decoupling - to maintain this performance in production systems.