NXP Semiconductors 74AHC125D,112

Overview

74AHC125D,112 from Nexperia is a quad CMOS buffer/line driver with 3-state outputs, designed for bidirectional bus interfacing and voltage-level translation in mixed-supply systems. It operates from 2.0 V to 5.5 V, features overvoltage-tolerant inputs up to 5.5 V, and delivers balanced propagation delays (3.0–8.0 ns at VCC = 5 V, CL = 15 pF). Its four independent channels support high-noise-immunity digital signal routing in industrial control backplanes.

For engineers reviewing the 74AHC125D,112 datasheet, 74AHC125D,112 pinout, 74AHC125D,112 application, or 74AHC125D,112 equivalent, this device is selected for its rail-to-rail input tolerance, low ICC (≤40 μA at VCC = 5.5 V), Schmitt-trigger input action, -40 °C to +125 °C operation, and SO14 package compatibility with legacy PCB footprints.

Technical Context

The 74AHC125D implements four identical non-inverting buffers, each with an active-low 3-state output enable (nOE) controlling high-impedance isolation. Each channel accepts CMOS-level inputs and drives TTL- or CMOS-compatible loads with symmetrical rise/fall times and matched tPLH/tPHL propagation characteristics.

Its overvoltage-tolerant inputs (VI up to 5.5 V regardless of VCC) enable use as a level translator between 3.3 V logic domains and 5 V peripherals without external biasing. The device includes Schmitt-trigger inputs for noise rejection on slow or noisy signals and meets JESD 78 Class II latch-up immunity (>100 mA).

Key Specifications

Pinout & Package

74AHC125D,112 is housed in a plastic small outline package (SO14, SOT108-1) with 14 leads and 3.9 mm body width. Pin 1 is marked by a notch or index area; the package is RoHS-compliant and lead-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad buffer/line driver applications.

Compared with 74AHCT125D,112, the 74AHC125D,112 provides higher noise immunity and safer 5 V signal acceptance, while SN74LVC125APWR trades voltage flexibility for higher drive and smaller size-making AHC the default choice for interoperability-critical industrial interfaces.

Availability

74AHC125D,112 is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, microcontroller GPIO expansion, and test equipment signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for 74AHC125D,112 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

Nexperia is a global semiconductor expert delivering high-performance logic, analog, and MOSFET solutions optimized for efficiency, reliability, and manufacturability in high-volume applications.

The 74AHC series targets general-purpose digital interfacing where robustness, wide supply range, and mixed-voltage compatibility are essential - particularly in industrial automation, automotive sub-systems, and instrumentation.

FAQ

Can 74AHC125D,112 safely interface a 5 V sensor output with a 3.3 V microcontroller?

Yes. Its inputs tolerate up to 5.5 V regardless of VCC, allowing direct connection of 5 V sensor outputs to the 74AHC125D,112 powered at 3.3 V. The output will swing rail-to-rail (0 V to 3.3 V), matching the MCU's input thresholds. No external resistors or clamps are needed, provided output load capacitance stays ≤50 pF.

What is the maximum clock frequency supported when using 74AHC125D,112 as a data bus driver?

While not a clock device, the 74AHC125D,112 supports data rates up to ~100 MHz in practice. With tpd = 5.5 ns (max at VCC = 5 V, CL = 15 pF) and tdis = 9.0 ns (max), it maintains signal integrity for NRZ data streams where edge-to-edge spacing exceeds 15 ns. For reliable 50 MHz parallel bus operation, ensure trace lengths are impedance-controlled and terminated.

Does the SO14 package (SOT108-1) of 74AHC125D,112 require thermal pad soldering?

No. The SO14 package has no exposed thermal pad. Thermal dissipation relies on copper pour connected to pins 7 (GND) and 14 (VCC). For continuous 500 mW operation, use ≥25 mm² internal copper area per pin with 2+ thermal vias to inner ground planes. Derating begins at 100 °C ambient (10.1 mW/K).

How does the Schmitt-trigger input improve performance in noisy environments?

The Schmitt-trigger action provides ~0.3 V hysteresis at VCC = 3.3 V, meaning VIH ≈ 1.9 V and VIL ≈ 1.6 V. This prevents multiple transitions on slowly rising or noisy signals - such as those from mechanical switches or long cables - ensuring clean, single-edge detection without software debouncing or RC filtering.