Texas Instruments SN74LVTH125DBR

Overview

SN74LVTH125DBR from Texas Instruments is a quad 3-state noninverting buffer designed for mixed-voltage bus interfacing between 3.3-V logic and 5-V TTL systems. It supports VCC down to 2.7 V, features bus-hold on all data inputs, Ioff for hot insertion, and delivers 64 mA sink current per output at 3.3 V - enabling robust signal translation in industrial backplanes and embedded control buses.

For engineers reviewing the SN74LVTH125DBR datasheet, SN74LVTH125DBR pinout, SN74LVTH125DBR application, or SN74LVTH125DBR equivalent, key selection criteria include its 3.3-V supply compatibility with 5-V tolerant inputs, guaranteed 4.9 ns enable/disable timing, bus-hold functionality eliminating external resistors, and SSOP-14 package thermal performance (θJA = 96°C/W).

Technical Context

The SN74LVTH125DBR implements four independent noninverting buffers, each with active-low 3-state output control (OE). Its TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V) and 5-V tolerant inputs allow direct connection to legacy 5-V logic while operating from a 3.3-V rail. Bus-hold circuitry maintains valid logic states on undriven inputs without external pull resistors.

Hot-insertion support is achieved via Ioff (±100 µA max at VCC = 0) and power-up 3-state logic that forces outputs into high-impedance during VCC ramp from 0 to 1.5 V. Output ground bounce (VOLP < 0.8 V at TA = 25°C) and latch-up immunity (>500 mA per JESD 17) ensure signal integrity in noisy, multi-drop environments.

Key Specifications

Pinout & Package

SN74LVTH125DBR uses a 14-pin SSOP (Shrink Small Outline Package) with 0.65-mm lead pitch, 7.4-mm body width, and 2.0-mm maximum height. The package is RoHS-compliant, moisture-sensitive level 1 (260°C reflow), and optimized for automated SMT assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125APWR and SN74AHCT125PW, the SN74LVTH125DBR uniquely combines 5-V input tolerance, bus-hold, Ioff, and 3.3-V operation - making it the sole option for robust hot-pluggable mixed-voltage bus interfaces requiring zero external bias components.

Availability

SN74LVTH125DBR is available at Aetrix Electronics and suitable for industrial backplane interfaces, embedded control buses, telecom line cards, and automated test equipment requiring stable component supply across extended temperature ranges (−40°C to 85°C).

Supply support for SN74LVTH125DBR 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 for industrial, automotive, and communications markets.

The SN74LVTH125DBR belongs to TI's LVTH logic family, engineered specifically for mixed-voltage system interfacing - delivering 3.3-V operation with 5-V signal compatibility, bus-hold, and hot-insertion robustness in space-constrained packages.

FAQ

What is the maximum input voltage rating for SN74LVTH125DBR?

The SN74LVTH125DBR supports input voltages up to 5.5 V regardless of VCC level, enabling direct connection to 5-V TTL outputs while powered from a 3.3-V supply. This 5-V tolerance is specified across the full operating temperature range and does not require external clamping diodes.

Does SN74LVTH125DBR require external pullup resistors on its inputs?

No - SN74LVTH125DBR integrates bus-hold circuitry on all data inputs (1A–4A), actively maintaining valid logic states on undriven or floating lines. Using external pullup or pulldown resistors with bus-hold enabled is explicitly discouraged in the datasheet and may cause excessive current draw or logic instability.

Can SN74LVTH125DBR be used in hot-swap applications?

Yes - SN74LVTH125DBR is fully specified for hot-insertion use via two key features: Ioff circuitry limits current flow when VCC = 0, and power-up 3-state forces outputs into high-impedance during VCC ramp from 0 to 1.5 V, preventing bus conflicts during live board insertion.

What is the thermal resistance (θJA) of SN74LVTH125DBR in its SSOP package?

The SN74LVTH125DBR in the SSOP-14 (DB) package has a junction-to-ambient thermal resistance (θJA) of 96°C/W, measured per JESD 51-7. This value assumes standard JEDEC high-K test board conditions and guides thermal derating for continuous operation at elevated ambient temperatures.

How does the bus-hold feature behave at VCC = 2.7 V?

At VCC = 2.7 V, the SN74LVTH125DBR's bus-hold circuitry remains fully functional, maintaining input states with ±75 µA hold current (per datasheet Section 4, II(hold)). This ensures reliable operation across the entire specified VCC range without degradation in noise immunity or state retention.