Texas Instruments SN74AHC125NS

Overview

SN74AHC125NS from Texas Instruments is a quad non-inverting 3-state buffer/line driver with active-low output enable inputs, designed for bus interface and signal isolation in 2.0 V to 5.5 V digital systems. It delivers balanced propagation delays (as low as 3.0 ns at VCC = 5.0 V, CL = 15 pF), ±8 mA output drive, and operates across −40 °C to +125 °C. Used in microcontroller I/O expansion, memory address buffering, and logic-level translation between CMOS domains.

For engineers reviewing the SN74AHC125NS datasheet, SN74AHC125NS pinout, SN74AHC125NS application, or SN74AHC125NS equivalent, this page provides verified functional identity, validated SO-14 pin mapping, confirmed CMOS-input-level compatibility, temperature-rated static/dynamic specs, and real-world substitution guidance - all aligned to TI's official SN74AHC125NS datasheet (SCAS589H).

Technical Context

The SN74AHC125NS implements four independent non-inverting buffers, each with an active-low 3-state output enable (nOE) controlling high-impedance OFF-state transitions. Its input structure accepts voltages up to 7.0 V regardless of VCC, enabling mixed-voltage interfacing without level shifters.

It features Schmitt-trigger action on all inputs for noise immunity, supports CMOS input thresholds (VIH ≥ 3.85 V at VCC = 5.5 V), and maintains rail-to-rail output swing (VOH ≥ 4.4 V, VOL ≤ 0.36 V at IO = −8 mA / +8 mA) under full industrial temperature range.

Key Specifications

Pinout & Package

SN74AHC125NS is supplied in a 14-pin plastic small outline package (SO-14), body width 3.9 mm, JEDEC MS-012 compliant, with standard 1.27 mm lead pitch and gull-wing leads. Pin 1 is marked by a beveled corner or index notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AHC125NS, SN74AHCT125NSR offers guaranteed TTL input compatibility at the cost of higher leakage, while 74LVC125AD,118 trades SO-14 compatibility for smaller size and broader voltage support - both require validation of timing margins and thermal derating in high-density layouts.

Availability

SN74AHC125NS is available at Aetrix Electronics and suitable for microcontroller I/O expansion, memory address buffering, FPGA configuration interfaces, and logic-level translation requiring stable component supply across automotive, industrial, and embedded computing programs.

Supply support for SN74AHC125NS 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, with over 50 years of innovation in logic and interface ICs.

SN74AHC125NS belongs to the SN74AHC advanced high-speed CMOS logic family, engineered for low-power, high-noise-immunity digital interfacing in industrial, automotive, and communications equipment.

FAQ

What is the maximum operating supply voltage for SN74AHC125NS?

The absolute maximum supply voltage for SN74AHC125NS is +7.0 V, but the recommended operating range is 2.0 V to 5.5 V per TI's SCAS589H datasheet. Operation above 5.5 V risks exceeding internal oxide limits and is not characterized for timing or drive strength. For sustained reliability, maintain VCC within 2.0–5.5 V and use proper decoupling.

Does SN74AHC125NS support mixed-voltage interfacing?

Yes, SN74AHC125NS supports mixed-voltage interfacing: its inputs tolerate −0.5 V to +7.0 V independently of VCC, allowing safe connection to 5 V TTL signals even when powered at 3.3 V. Outputs swing rail-to-rail, so VOH ≈ VCC and VOL ≈ 0 V - no external level-shifting circuitry is needed for basic voltage domain bridging.

What is the function of the nOE pins on SN74AHC125NS?

SN74AHC125NS has four active-low output enable inputs (pins 1, 4, 10, 13). When nOE is LOW, the corresponding buffer output (nY) follows the input (nA); when nOE is HIGH, that output enters high-impedance (Z) state, electrically disconnecting it from the bus. This enables time-multiplexed sharing of signal lines among multiple drivers.

Can SN74AHC125NS replace SN74LS125 in existing designs?

SN74AHC125NS is pin-compatible with SN74LS125 and meets JEDEC JESD7-A, but differs in electrical behavior: it draws far less supply current (µA vs mA), has CMOS input thresholds (not TTL), and requires no pull-up resistors. Direct replacement is possible only if the host system supplies 2.0–5.5 V and uses CMOS-compatible logic levels - verify VIH/VIL margins before substitution.

What package type does SN74AHC125NS use?

SN74AHC125NS uses a 14-pin plastic small outline package (SO-14), also known as SOIC-14 or MS-012, with 1.27 mm lead pitch, 3.9 mm body width, and gull-wing leads. It is RoHS-compliant, halogen-free, and specified for reflow soldering per JEDEC J-STD-020. The package code "NS" explicitly denotes this SO-14 variant.