Texas Instruments SN74LVTH125D

Overview

SN74LVTH125D 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 operates from 2.7 V to 3.6 V, supports hot insertion via Ioff and power-up 3-state, features bus-hold on all data inputs, and delivers 64 mA low-level output drive at VCC = 3 V - used in industrial backplane interface and FPGA-to-legacy peripheral bridging.

For engineers reviewing the SN74LVTH125D datasheet, SN74LVTH125D pinout, SN74LVTH125D application, or SN74LVTH125D equivalent, key selection criteria include its 3.3-V VCC compatibility with 5-V tolerant inputs, guaranteed 4.9 ns enable/disable timing (tPZH/tPZL), bus-hold elimination of external resistors, and SOIC-14 package thermal performance (θJA = 86°C/W).

Technical Context

The SN74LVTH125D implements four independent noninverting buffers, each with dedicated 3-state output-enable (OE) control. Its bus-hold circuitry actively maintains valid logic states on undriven inputs without external components, and Ioff protection disables outputs during power-down to prevent current backflow.

Each buffer exhibits propagation delays ≤4.7 ns (tPLH/tPHL at VCC = 3.3 V), supports input voltages up to 5.5 V regardless of VCC, and guarantees high-impedance outputs when OE is high - enabling bidirectional bus arbitration in shared-data-path architectures.

Key Specifications

Pinout & Package

SN74LVTH125D uses a 14-pin SOIC (D) package with 1.27 mm pitch, 8.75 mm × 3.91 mm body, and 1.75 mm max height per JEDEC MS-012 AB. Thermal pad not present; standard lead-free NIPDAU finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125D and SN74AHCT125D, the SN74LVTH125D uniquely combines 3.3-V operation, 5-V input tolerance, integrated bus-hold, and Ioff-based hot-swap safety - making it the sole choice for robust mixed-voltage backplane and FPGA-peripheral bridging where pin count, reliability, and layout simplicity are critical.

Availability

SN74LVTH125D is available at Aetrix Electronics and suitable for industrial backplane interface, FPGA-to-peripheral bridging, and embedded memory expansion requiring stable component supply across extended temperature ranges (−40°C to 85°C) and long-lifecycle production programs.

Supply support for SN74LVTH125D 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 solutions for industrial, automotive, and communications markets.

The SN74LVTH125D belongs to TI's LVTH logic family, engineered specifically for mixed-voltage bus interfacing in systems transitioning from 5-V TTL to 3.3-V logic while maintaining backward compatibility and robustness.

FAQ

What is the maximum input voltage rating for SN74LVTH125D?

The SN74LVTH125D supports input voltages up to 5.5 V regardless of VCC level, enabling direct connection to 5-V TTL outputs without external level-shifting circuitry. This specification is guaranteed across the full operating temperature range (−40°C to 85°C) and is explicitly validated in the absolute maximum ratings table of the SCBS703I datasheet.

Does SN74LVTH125D require external pullup resistors on its inputs?

No, the SN74LVTH125D integrates active bus-hold circuitry on all data inputs (1A–4A), which maintains a valid logic state when inputs are floating or undriven. Using external pullup or pulldown resistors with the bus-hold function is explicitly discouraged in the datasheet, as it may cause contention and increased power consumption.

Can SN74LVTH125D be used in hot-insertion applications?

Yes, the SN74LVTH125D is fully specified for hot-insertion applications using both Ioff and power-up 3-state technologies. The Ioff circuitry disables outputs during power-down to prevent damaging current backflow, while the power-up 3-state ensures outputs remain in high-impedance until VCC stabilizes above 1.5 V - both confirmed in the functional description and recommended operating conditions.

What is the thermal resistance (θJA) of SN74LVTH125D in its SOIC package?

The SN74LVTH125D in the SOIC (D) package has a junction-to-ambient thermal resistance (θJA) of 86°C/W, as measured per JESD 51-7. This value applies to standard JEDEC 2-layer board conditions and is critical for thermal derating calculations in enclosed industrial enclosures or high-density PCB layouts.

How does the bus-hold feature behave at different VCC levels?

The bus-hold circuitry in SN74LVTH125D operates across the full VCC range (2.7 V to 3.6 V), with hold current specified as ±75 µA at VCC = 3 V and ±500 µA at VCC = 3.6 V (dynamic maximum). This ensures reliable state retention on floating inputs even during brownout conditions or low-VCC battery operation, as verified in the electrical characteristics table.