Texas Instruments SN74HCS125PWR

Overview

SN74HCS125 from Texas Instruments is a quadruple non-inverting buffer IC with 3-state outputs and Schmitt-trigger inputs, operating across 2V–6V supply. It delivers ±7.8mA output drive at 6V, features 100nA typical ICC, supports –40°C to +125°C ambient operation, and enables digital signal gating in noise-prone industrial control interfaces.

For engineers reviewing the SN74HCS125 datasheet, SN74HCS125 pinout, SN74HCS125 application, or SN74HCS125 equivalent, key selection criteria include Schmitt-trigger hysteresis (ΔVT ≥ 0.55V), 3-state enable timing (ten ≤ 9ns at 6V), propagation delay (tpd ≤ 24ns at 6V), and TSSOP-14 package compatibility with high-density PCB layouts.

Technical Context

The SN74HCS125 implements four independent Y = A positive-logic buffers, each controlled by an active-low output-enable (OE) input. Its Schmitt-trigger inputs provide 0.55–1.49V hysteresis (ΔVT) across 2–6V VCC, enabling reliable operation with slow-rising or noisy signals without external conditioning.

Each channel offers balanced CMOS push-pull outputs capable of sourcing/sinking up to ±7.8mA at 6V while maintaining VOL ≤ 0.33V and VOH ≥ 5.4V. The device enters high-impedance (Hi-Z) state when OE is high, supporting bus-sharing and signal isolation in multi-driver systems.

Key Specifications

Pinout & Package

TSSOP-14 (PW) package: 5.00mm × 4.40mm body, 0.65mm pitch, exposed thermal pad (not present in PW variant), RoHS-compliant matte tin lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCS126PWR and SN74LV125APWR, the SN74HCS125PWR uniquely balances wide supply range, Schmitt-trigger robustness, and ultra-low power-making it optimal for industrial sensing and mixed-voltage signal routing where reliability outweighs raw speed.

Availability

SN74HCS125PWR is available at Aetrix Electronics and suitable for industrial sensor interfaces, automotive body control modules, and programmable logic I/O expansion requiring stable component supply across extended temperature and voltage ranges.

Supply support for SN74HCS125PWR 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 and embedded processing technologies, with decades of expertise in logic, power management, and signal chain solutions.

The SN74HCS125 belongs to TI's HCS logic family, designed for robust, low-power signal buffering in harsh environments-targeting industrial automation, automotive subsystems, and IoT edge nodes where noise immunity and wide-VCC operation are essential.

FAQ

What is the maximum capacitive load the SN74HCS125PWR can drive while meeting datasheet specifications?

The SN74HCS125PWR is specified to drive loads with total capacitance ≤50pF while maintaining guaranteed switching characteristics and output voltage levels. Exceeding this value may increase propagation delay, degrade edge rates, or cause timing violations in high-speed interfaces. For larger loads, consider adding a series resistor or using a dedicated driver stage.

Does the SN74HCS125PWR require external pull-up or pull-down resistors on unused inputs?

Yes, unused inputs of the SN74HCS125PWR must be terminated to either VCC or GND to prevent floating states that could cause excessive current draw or erratic output behavior. A 10kΩ resistor is commonly used due to its balance of leakage suppression and minimal impact on signal integrity. Schmitt-trigger inputs do not require fast transition rates but still demand defined DC bias.

Can the SN74HCS125PWR outputs be paralleled for higher current drive?

Yes, two or more channels of the SN74HCS125PWR with identical inputs and OE states can be paralleled to increase output current capability. This configuration maintains logic consistency and distributes thermal load. Ensure matched OE control and avoid mixing enabled/disabled channels on shared nets to prevent shoot-through current.

What is the significance of the ΔVT parameter for the SN74HCS125PWR in real-world applications?

The ΔVT (input hysteresis) of the SN74HCS125PWR-ranging from 0.55V to 1.49V depending on VCC-defines the minimum peak-to-peak noise amplitude the device rejects before misinterpreting logic transitions. In practice, this enables reliable operation with mechanical switches, long unshielded cables, or noisy power rails without external filtering components.

Is the SN74HCS125PWR compatible with 1.8V logic systems?

No, the SN74HCS125PWR has a minimum recommended supply voltage of 2V and is not rated for reliable operation at 1.8V. Attempting to use it below 2V may result in undefined output states, increased ICC, or failure to meet timing specifications. For 1.8V systems, consider the SN74LVC1G125 or SN74AUP1G125 families instead.