Texas Instruments SN74LVC2G125DCTR

Overview

SN74LVC2G125DCTR from Texas Instruments is a dual 3-state bus buffer gate IC designed for 1.65-V to 5.5-V operation, featuring two independent noninverting buffers with active-low output-enable controls (1OE, 2OE), ±24-mA drive at 3.3 V, 4.3-ns max propagation delay, and Ioff support for live insertion in partial-power-down systems. It is used in high-speed data acquisition, video infrastructure, and SSD interconnects.

For engineers reviewing the SN74LVC2G125DCTR datasheet, SN74LVC2G125DCTR pinout, SN74LVC2G125DCTR application, or SN74LVC2G125DCTR equivalent, key selection considerations include 3-state output timing control, overvoltage-tolerant inputs up to 5.5 V, NanoFree™ SM8 package compatibility, and Ioff-enabled back-drive protection during power sequencing.

Technical Context

The SN74LVC2G125DCTR implements two independent CMOS buffer channels, each with a dedicated active-low output-enable input controlling high-impedance (Z) or driven (Y = A) output states. Its balanced push-pull outputs deliver symmetrical sourcing/sinking capability, enabling fast edge rates into light loads while requiring careful PCB routing to suppress ringing.

It supports voltage translation: inputs tolerate up to 5.5 V regardless of VCC (1.65–5.5 V), allowing down-translation from higher-voltage domains. The Ioff circuitry ensures all I/O pins enter high-impedance when VCC = 0 V, preventing current backflow during hot-swap or power-down sequences.

Key Specifications

Pinout & Package

SN74LVC2G125DCTR is housed in an 8-pin SM8 (Small Outline Package, 2.95 mm × 2.80 mm) with exposed pad, part of Texas Instruments' NanoFree™ packaging technology where the silicon die serves as the package substrate.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC2G125DCTR, SN74LVC2G126DCTR provides inverted logic essential for specific control architectures, while 74LVC2G125GW,115 offers a smaller XSON8 footprint at the cost of ~0.4 ns longer propagation delay and different thermal metrics - both require validation of layout and timing margins in final design.

Availability

SN74LVC2G125DCTR is available at Aetrix Electronics and suitable for high-speed data acquisition, video broadcasting infrastructure, and SSD controller interconnects requiring stable component supply, long-term lifecycle assurance, and traceable industrial-grade sourcing.

Supply support for SN74LVC2G125DCTR 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 power management ICs.

The SN74LVC2G125DCTR belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for robust voltage translation, low-power 3-state bus management, and industrial temperature operation in space- and power-constrained systems.

FAQ

What is the recommended pull-up resistor value for OE pins on the SN74LVC2G125DCTR?

The SN74LVC2G125DCTR datasheet specifies that OE pins should be tied to VCC via a pull-up resistor to ensure high-impedance state during power-up or power-down. The minimum resistor value depends on the current-sinking capability of the driving source; typical values range from 4.7 kΩ to 10 kΩ for 3.3-V systems. For precise sizing, refer to the maximum I_OL of the OE driver in your system and apply Ohm's law using V_CC − V_OL.

Does the SN74LVC2G125DCTR support 5-V operation?

Yes, the SN74LVC2G125DCTR supports VCC operation from 1.65 V to 5.5 V, and its inputs are overvoltage tolerant up to 5.5 V. When VCC = 5 V, it delivers ±32-mA output drive and maintains 3.7-ns max propagation delay, making it fully compatible with 5-V TTL/CMOS logic families while retaining 3-state control and Ioff protection.

Can the SN74LVC2G125DCTR be used for level translation between different voltage domains?

Yes, the SN74LVC2G125DCTR functions as a unidirectional down-translator: inputs accept up to 5.5 V regardless of VCC, while outputs swing between GND and the applied VCC. For example, with VCC = 2.5 V, a 5-V input signal produces a 2.5-V output - enabling direct interface between 5-V sensors and 2.5-V microcontrollers without external level shifters.

What is the thermal resistance (RθJA) of the SN74LVC2G125DCTR in its SM8 package?

The SN74LVC2G125DCTR in the DCT (SM8) package has a junction-to-ambient thermal resistance (RθJA) of 199.0°C/W, as specified in the TI datasheet SCES204Q. This value assumes standard JEDEC high-K board conditions; actual thermal performance improves with PCB copper area, thermal vias, and airflow - critical for sustained ±24-mA output loading at elevated ambient temperatures.

How does the Ioff feature of the SN74LVC2G125DCTR protect the device during partial power-down?

The Ioff circuitry in the SN74LVC2G125DCTR disables all input and output paths when VCC = 0 V, limiting leakage current to ±10 µA maximum. This prevents damaging back-current flow from powered sections of the system into the unpowered SN74LVC2G125DCTR, protecting against latch-up and enabling safe live insertion in modular backplane or hot-swap applications.