Texas Instruments SN74LVT125PWG4

Overview

SN74LVT125PWG4 from Texas Instruments is a quad 3-state noninverting buffer designed for mixed-mode 3.3-V V_CC operation with 5-V tolerant inputs and outputs, supporting TTL-level interfacing in low-voltage systems. It features bus-hold circuitry on all data inputs, I_off partial-power-down protection, and operates down to 2.7 V supply voltage. Used in voltage-level translation between 3.3-V logic domains and legacy 5-V buses.

For engineers reviewing the SN74LVT125PWG4 datasheet, SN74LVT125PWG4 pinout, SN74LVT125PWG4 application, or SN74LVT125PWG4 equivalent, key selection considerations include its 3.3-V core compatibility with 5-V signal tolerance, bus-hold input retention, I_off current blocking during power-down, propagation delay under 4.9 ns at 3.3 V, and TSSOP-14 package thermal performance (θ_JA = 113°C/W).

Technical Context

This device implements four independent noninverting buffers, each with an active-low 3-state output-enable (OE) control. The bus-hold circuitry actively maintains valid logic states on undriven inputs without external resistors, eliminating floating node risks in high-impedance bus environments.

I_off functionality disables output drivers when V_CC = 0 V, preventing backflow current from powered downstream circuits into the unpowered IC. Input voltage range extends to 5.5 V, enabling direct connection to 5-V TTL sources while operating from a 3.3-V supply - critical for mixed-voltage board designs.

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 SN74LVT125PWG4, SN74LVC125APWR trades 5-V tolerance for wider V_CC flexibility, while 74ALVC125MTCX offers faster timing but increases design complexity via external bus termination - making SN74LVT125PWG4 optimal for robust, drop-in mixed-voltage buffering with zero external components.

Availability

SN74LVT125PWG4 is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and test equipment requiring stable component supply across extended temperature ranges (−40°C to 85°C) and long-lifecycle production programs.

Supply support for SN74LVT125PWG4 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 90 years of innovation in industrial, automotive, and communications markets.

The SN74LVT125PWG4 belongs to TI's LVT (Low-Voltage BiCMOS Technology) logic family, engineered for high-speed, mixed-voltage interfacing in systems transitioning from 5-V to 3.3-V architectures while maintaining backward compatibility.

FAQ

What is the maximum input voltage rating for SN74LVT125PWG4?

The SN74LVT125PWG4 supports an absolute maximum input voltage of 5.5 V, allowing direct connection to 5-V TTL outputs while operating from a 3.3-V supply. This 5-V tolerance is maintained across the full recommended operating temperature range (−40°C to 85°C) and does not require external clamping diodes or resistive dividers when interfacing with standard 5-V logic families.

Does SN74LVT125PWG4 require external pullup resistors on its inputs?

No, SN74LVT125PWG4 does not require external pullup resistors because it integrates bus-hold circuitry on all data inputs (pins 2, 5, 11, 14). This feature actively maintains a valid logic state on undriven or floating inputs, eliminating undefined behavior during power-up, reset, or tri-state conditions - a key advantage over standard LVC or LS logic buffers.

Can SN74LVT125PWG4 be used in partial-power-down applications?

Yes, SN74LVT125PWG4 supports partial-power-down operation via its I_off circuitry, which limits current to ±100 µA when V_CC = 0 V. This prevents damaging backflow current from powered downstream circuits into the unpowered SN74LVT125PWG4, making it suitable for hot-swap, modular backplane, and power-sequenced systems where subsystems power up/down independently.

What is the thermal resistance (θ_JA) of the SN74LVT125PWG4 package?

The SN74LVT125PWG4 uses a TSSOP-14 (PW) package with a specified junction-to-ambient thermal resistance (θ_JA) of 113°C/W under standard JEDEC test conditions. This value guides PCB layout decisions - including copper pour area, thermal vias, and airflow - to ensure junction temperature remains within safe limits (<125°C) at maximum sustained power dissipation (≈70 mW typical).

How does the output-enable (OE) pin function on SN74LVT125PWG4?

Each of the four OE pins (1, 4, 10, 13) on SN74LVT125PWG4 controls its associated buffer independently: when OE is low, the corresponding Y output (pins 3, 6, 12, 9) drives the inverted or noninverted A input signal; when OE is high, that Y output enters high-impedance state. To ensure defined outputs during power-up, TI recommends tying OE to V_CC via a pullup resistor sized for the driver's sink capability.