Texas Instruments SN74LV125ATDR

Overview

SN74LV125ATDR from Texas Instruments is a quadruple 3-state bus buffer gate IC used for bidirectional data isolation and bus driving in 5-V digital systems. It features four independent channels, TTL-compatible inputs, 4.5–5.5-V operation, 3.8-ns typical propagation delay at 5 V, and Ioff support for partial-power-down mode. It is commonly deployed in microcontroller peripheral expansion, memory address/data bus buffering, and level-translating logic interfaces.

For engineers reviewing the SN74LV125ATDR datasheet, SN74LV125ATDR pinout, SN74LV125ATDR application, or SN74LV125ATDR equivalent, key selection criteria include 3-state output timing (tpd, ten, tdis), mixed-mode voltage tolerance, ground bounce (VOLP) and undershoot (VOHV) performance, Ioff leakage under power-down, and SOIC-14 package compatibility with legacy 5-V PCB layouts.

Technical Context

The SN74LV125ATDR implements four identical non-inverting buffer stages, each with an active-low 3-state output-enable (OE) input. Each channel operates independently: when OE is low, the output Y follows input A; when OE is high, Y enters high-impedance state. The device uses LV-CMOS logic with TTL-voltage-compatible inputs, enabling direct interfacing with legacy 5-V TTL outputs without level shifters.

Its Ioff circuitry actively disables both input and output terminals during power-down, limiting off-state leakage to ≤5 µA across 0–5.5 V, preventing back-drive current into powered subsystems. Thermal resistance (RθJA) is 86°C/W in the SOIC-14 (D) package, supporting continuous operation from –40°C to +125°C under recommended conditions.

Key Specifications

Pinout & Package

SN74LV125ATDR is packaged in a 14-pin SOIC (D) body measuring 8.65 mm × 6.00 mm with 1.27-mm lead pitch and 1.75-mm max height. The package is RoHS-compliant, lead-finished with NiPdAu/Sn, and rated MSL-1 (unlimited floor life at ≤30°C/60% RH).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV125ATDR, SN74LVC125APWR offers better efficiency at 3.3 V but cannot replace it in 5-V/TTL environments, while 74ACT125SCX delivers superior speed and drive but sacrifices Ioff safety-making SN74LV125ATDR the optimal choice for robust, mixed-voltage, power-aware bus isolation.

Availability

SN74LV125ATDR is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, and legacy-system upgrade projects requiring stable component supply and long-term manufacturability.

Supply support for SN74LV125ATDR 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 connectivity technologies, with decades of experience in high-reliability logic and interface solutions.

The SN74LV125ATDR belongs to TI's LV family of 5-V tolerant CMOS logic devices, engineered specifically for robust bus buffering, level translation, and power-aware system integration in industrial and automotive applications.

FAQ

What is the recommended power supply decoupling for SN74LV125ATDR?

Place a 0.1-µF ceramic capacitor between VCC (pin 14) and GND (pin 7), located as close as possible to the device. For systems with heavy switching loads, add a 4.7-µF bulk capacitor nearby. This minimizes supply noise and ensures stable 3-state transitions and propagation delay consistency across all four channels of the SN74LV125ATDR.

Does SN74LV125ATDR support mixed-voltage operation between input and output sides?

Yes, SN74LV125ATDR supports mixed-mode voltage operation: inputs tolerate 0–5.5 V regardless of VCC, and outputs drive to VCC levels. This allows interfacing a 3.3-V controller's outputs to the A inputs while powering VCC at 5 V to drive 5-V peripherals - a key capability confirmed in Section 1 Features and Section 7.1 Overview of the SN74LV125ATDR datasheet.

How does the Ioff feature function in SN74LV125ATDR during system power-down?

The Ioff circuitry in SN74LV125ATDR actively disables both inputs and outputs when VCC = 0 V, limiting leakage current to ≤5 µA even with up to 5.5 V applied to any pin. This prevents back-driving powered sections of the system - a critical safeguard during partial power-down sequences in modular or hot-swap-capable designs using the SN74LV125ATDR.

Can SN74LV125ATDR replace older 74LS125 devices in existing designs?

SN74LV125ATDR is a functional and pin-compatible upgrade for 74LS125 in 5-V systems: same SOIC-14 footprint, identical pinout, TTL-compatible inputs, and 3-state outputs. It improves on LS technology with lower power (2 µA ICC), faster speed (3.8 ns vs. 15 ns), and Ioff protection - making SN74LV125ATDR a drop-in reliability and performance enhancement.

What is the maximum capacitive load SN74LV125ATDR can drive while maintaining specified timing?

SN74LV125ATDR is characterized for CL = 15 pF (tpd = 3.8 ns) and CL = 50 pF (tpd = 5.3 ns) in its switching characteristics table. While it can drive heavier loads, propagation delay increases linearly with capacitance; for reliable timing closure beyond 50 pF, derating or simulation with IBIS models is advised. All published SN74LV125ATDR timing specs assume these defined load conditions.