Texas Instruments SN74LVTH125PWG4

Overview

SN74LVTH125PWG4 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 I_off and power-up 3-state, and features bus-hold on all data inputs to eliminate external pull resistors. Used in backplane interface, memory expansion, and industrial control bus isolation.

For engineers reviewing the SN74LVTH125PWG4 datasheet, SN74LVTH125PWG4 pinout, SN74LVTH125PWG4 application, or SN74LVTH125PWG4 equivalent, key selection criteria include its 3.3-V V_CC compatibility with 5-V input tolerance, bus-hold functionality, output drive strength (64 mA sink), thermal performance (θ_JA = 113°C/W), and TSSOP-14 package suitability for high-density PCB layouts.

Technical Context

The SN74LVTH125PWG4 implements four independent noninverting buffers, each with an active-low 3-state output-enable (OE) input. Its bus-hold circuitry maintains stable logic states on undriven inputs without external components, reducing system BOM count and layout complexity.

Designed for hot-insertion environments, it uses I_off protection to block current backflow during power-down and power-up 3-state logic to force outputs into high-impedance before V_CC stabilizes-preventing bus contention during live board swaps or partial power sequencing.

Key Specifications

Pinout & Package

TSSOP-14 (PW) package: 4.4 mm × 5.0 mm body, 0.65 mm lead pitch, 1.2 mm max height, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC125PW and SN74AHCT125PW, the SN74LVTH125PWG4 uniquely combines 3.3-V operation, 5-V input tolerance, integrated bus-hold, and 64 mA drive-making it the sole option for robust, resistor-free mixed-voltage bus interfacing in space-constrained TSSOP layouts.

Availability

SN74LVTH125PWG4 is available at Aetrix Electronics and suitable for industrial control systems, test equipment signal routing, and embedded memory expansion requiring stable component supply and long-term production continuity.

Supply support for SN74LVTH125PWG4 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The SN74LVTH125 family targets mixed-signal bus interface applications where 3.3-V logic must interoperate with legacy 5-V TTL systems under harsh electrical conditions.

FAQ

What is the maximum input voltage the SN74LVTH125PWG4 can tolerate?

The SN74LVTH125PWG4 supports an input voltage range of −0.5 V to 5.5 V, allowing direct connection to 5-V TTL outputs while operating from a 3.3-V supply. This eliminates the need for external level-shifting circuitry and simplifies mixed-voltage system design. The device maintains valid logic thresholds and avoids damage even when driven by higher-voltage sources.

Does the SN74LVTH125PWG4 require external pullup or pulldown resistors on its inputs?

No, the SN74LVTH125PWG4 includes active bus-hold circuitry on all data inputs, which maintains a valid logic state on unused or undriven pins. Using external pull resistors with this feature is not recommended, as it may interfere with the internal hold current (±500 µA max). This integration reduces BOM count and PCB footprint in bus-interface applications.

Can the SN74LVTH125PWG4 be used in hot-swap applications?

Yes, the SN74LVTH125PWG4 is explicitly designed for hot-insertion use cases. Its I_off circuitry disables outputs and prevents damaging current backflow when powered down, while power-up 3-state ensures outputs remain in high-impedance until V_CC stabilizes above 1.5 V. These features protect both the SN74LVTH125PWG4 and the host system during live card replacement.

What is the thermal performance of the SN74LVTH125PWG4 in its TSSOP-14 package?

The SN74LVTH125PWG4 in the PW (TSSOP-14) package has a junction-to-ambient thermal resistance (θ_JA) of 113°C/W under standard JEDEC conditions. This value assumes a two-layer PCB with minimal copper; adding thermal vias and ground/power planes can significantly improve heat dissipation. The device is rated for continuous operation from −40°C to +85°C ambient.

How does the SN74LVTH125PWG4 handle power-up sequencing when V_CC ramps slowly?

When V_CC rises slowly (ramp rate ≤200 µs/V), the SN74LVTH125PWG4's power-up 3-state circuitry holds all outputs in high-impedance until V_CC exceeds 1.5 V. To guarantee high-Z behavior above that threshold, OE should be tied to V_CC via a pullup resistor sized for the driver's current-sinking capability-ensuring deterministic bus behavior during partial power events.