Texas Instruments SN74LVT125DR

Overview

SN74LVT125DR 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. It features bus-hold circuitry, I_off partial-power-down support, and operates down to 2.7 V. Used in voltage-level translation between 3.3-V logic domains and legacy 5-V systems, such as FPGA I/O interfacing or microcontroller peripheral expansion.

For engineers reviewing the SN74LVT125DR datasheet, SN74LVT125DR pinout, SN74LVT125DR application, or SN74LVT125DR equivalent, key selection considerations include its 3.3-V supply compatibility, 5-V input tolerance, bus-hold functionality eliminating external pullups, I_off protection during power sequencing, and SOIC-14 package suitability for industrial control and embedded communications boards.

Technical Context

The SN74LVT125DR implements four independent noninverting buffers, each with active-low output-enable (OE) control enabling high-impedance state on demand. Its bus-hold circuitry actively maintains valid logic levels at unused inputs without external resistors, reducing BOM count and layout complexity.

Designed for mixed-voltage system integration, it accepts 5-V TTL-level inputs while operating from a 2.7–3.6-V V_CC, and drives 5-V compatible outputs. The I_off feature disables outputs and limits current backflow when V_CC = 0, supporting hot-insertion and partial-power-down architectures.

Key Specifications

Pinout & Package

SN74LVT125DR is housed in a 14-pin SOIC (D) package per JEDEC MS-012AB, with 1.27-mm pitch, 8.75-mm body width, and 1.75-mm max height. Pin 1 is located at the top-left corner with notch or index mark.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVTH125DR and 74ALVC125DR, the SN74LVT125DR uniquely combines 7-V input tolerance, integrated bus-hold, and characterized I_off - making it the only option among the three that fully supports mixed-voltage, floating-input, and safe power-down use cases without design compromises.

Availability

SN74LVT125DR is available at Aetrix Electronics and suitable for industrial automation, embedded communications, and automotive body electronics requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.

Supply support for SN74LVT125DR 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 and level-shifting ICs.

The SN74LVT125DR belongs to TI's LVT (Low-Voltage BiCMOS Technology) logic family, engineered for seamless interoperability between 3.3-V and 5-V digital systems in industrial, telecom, and automotive applications.

FAQ

What is the maximum input voltage the SN74LVT125DR can tolerate?

The SN74LVT125DR supports an input voltage range of −0.5 V to 7 V, allowing direct connection to 5-V TTL sources without external clamping or level-shifting. This 7-V rating exceeds standard 5-V TTL swing and accommodates transient overvoltages common in industrial environments. The absolute maximum rating applies regardless of V_CC state, and the device maintains functional integrity within this range when operated within recommended conditions.

Does the SN74LVT125DR require external pullup resistors on its inputs?

No, the SN74LVT125DR does not require external pullup resistors because it integrates bus-hold circuitry on all data inputs (1A–4A). This internal circuit actively maintains a valid logic state when inputs are floating or undriven, with ±75 µA hold current at V_CC = 3 V. Using external resistors with bus-hold enabled is explicitly discouraged in the datasheet as it may cause contention or increased power consumption.

Can the SN74LVT125DR operate safely when V_CC is powered down to 0 V?

Yes, the SN74LVT125DR supports safe operation during V_CC power-down via its I_off feature. When V_CC = 0 V, the I_off circuitry disables all outputs and limits current flow to ±100 µA even if input or output pins are biased to 0–4.5 V. This prevents damaging back-current through the device, making it suitable for partial-power-down and hot-swap applications where subsystems power up/down asynchronously.

What is the propagation delay of the SN74LVT125DR at 3.3-V supply?

At V_CC = 3.3 V, the SN74LVT125DR exhibits a typical propagation delay of 2.7 ns (t_PLH) and 2.9 ns (t_PHL), with maximum values of 4 ns and 3.9 ns respectively, measured under CL = 50 pF. These delays remain consistent across the full operating temperature range (−40°C to 85°C), enabling predictable timing in synchronous data paths such as address/data bus conditioning or clock distribution fanout.

Is the SN74LVT125DR pin-compatible with other packages in the same family?

Yes, the SN74LVT125DR (SOIC-14) shares identical pinout and electrical functionality with SN74LVT125DBR (SSOP-14), SN74LVT125NSR (SOP-14), and SN74LVT125PWR (TSSOP-14). All variants implement the same 14-pin topology: OE/A/Y groups for four buffers plus GND and V_CC. Mechanical dimensions differ, but PCB layout can be adapted using footprint-compatible land patterns per TI's published board layout guidelines.