Texas Instruments SN74LVTH125NS

Overview

SN74LVTH125NS from Texas Instruments is a 3.3 V quad 3-state buffer with independent output enable inputs (1OE–4OE), TTL-compatible input/output switching levels, ±64 mA/−32 mA drive capability, and bus-hold inputs-designed for high-speed, low-power bus interfacing in mixed-voltage systems.

For engineers reviewing the SN74LVTH125NS datasheet, SN74LVTH125NS pinout, SN74LVTH125NS application, or SN74LVTH125NS equivalent, this device supports 5 V-tolerant inputs, live insertion/extraction, power-up 3-state behavior, and operates across −40 °C to +85 °C with SO14 packaging.

Technical Context

The SN74LVTH125NS implements four independent non-inverting buffers, each controlled by its own active-low 3-state enable input. Its BiCMOS architecture delivers low static current (0.13 mA typical) while maintaining sub-4 ns propagation delay (tPLH/tPHL = 2.7/2.9 ns typ. at 3.3 V, CL = 50 pF).

It features bus-hold circuitry on all data inputs (75–150 µA overdrive current), eliminating external pull-ups, and supports hot-plug operation with no bus current loading when outputs are tied to a 5 V bus. Input voltage tolerance extends to 5.5 V, enabling seamless interfacing with legacy 5 V logic.

Key Specifications

Pinout & Package

SN74LVTH125NS is supplied in SO14 (plastic small outline package, 14 leads, body width 3.9 mm, SOT108-1). Pin 1 is index-marked; exposed die pad is not electrically connected and must not be used as supply or signal terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVTH125NS, SN74LVC125A trades off 5 V tolerance and bus-hold for lower cost and wider VCC range, while 74ALVC124 retains 5 V tolerance but sacrifices drive strength and speed - making SN74LVTH125NS optimal for high-fidelity, drop-in 5 V bus interfacing with minimal external components.

Availability

SN74LVTH125NS is available at Aetrix Electronics and suitable for industrial PLC backplanes, embedded memory expansion, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SN74LVTH125NS 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 innovation in high-performance interface ICs.

The SN74LVTH125NS belongs to TI's LVT (Low-Voltage TTL) logic family, engineered specifically for high-speed, low-power 3.3 V bus interfacing in mixed-voltage systems with legacy 5 V compatibility.

FAQ

What is the maximum input voltage rating for SN74LVTH125NS?

The SN74LVTH125NS supports input voltages up to 5.5 V regardless of VCC level, enabling direct connection to 5 V logic without level-shifting circuitry. This 5 V tolerance applies to all data and enable inputs (1A–4A, 1OE–4OE), and is verified under recommended operating conditions with VI ≤ 5.5 V and ambient temperature −40 °C to +85 °C.

Does SN74LVTH125NS include bus-hold functionality, and how does it work?

Yes, SN74LVTH125NS integrates bus-hold circuitry on all four data inputs (1A–4A). Each input maintains its last-valid logic state using ±75 µA to ±150 µA overdrive current, eliminating the need for external pull-up or pull-down resistors. This feature is active at VCC = 3 V and prevents floating-input metastability in unconnected or unterminated bus scenarios.

Can SN74LVTH125NS be used in hot-swap applications?

Yes, SN74LVTH125NS supports live insertion and extraction due to its power-up 3-state behavior and bus-hold inputs. At power-on, all outputs remain in high-impedance until VCC stabilizes and enable signals are asserted, preventing bus contention. Combined with 5 V-tolerant inputs and no bus loading in OFF-state, it meets key requirements for modular backplane and field-replaceable unit designs.

What is the typical propagation delay of SN74LVTH125NS at 3.3 V?

The SN74LVTH125NS exhibits typical propagation delays of 2.7 ns (tPLH, LOW-to-HIGH) and 2.9 ns (tPHL, HIGH-to-LOW) at VCC = 3.3 V, CL = 50 pF, and Tamb = 25 °C. Over full temperature and voltage range (VCC = 2.7–3.6 V, −40 °C to +85 °C), worst-case delays are 4.0 ns and 3.9 ns respectively - supporting reliable operation in >250 MHz bus environments.

Is SN74LVTH125NS pin-compatible with other 74-series quad buffers?

SN74LVTH125NS uses the industry-standard SO14 pinout (SOT108-1) matching 74LVT125, 74LVTH125 variants, and legacy 74LS125. Pin functions (1OE–4OE, 1A–4A, 1Y–4Y, GND, VCC) are identical across these families. However, electrical differences - including drive strength, bus-hold presence, and 5 V tolerance - require validation in final system design before substitution.