onsemi MC74HCT14AFEL

Overview

MC74HCT14AFEL from onsemi is a hex Schmitt-trigger inverter IC with LSTTL-compatible inputs, designed for noise-immune signal conditioning and TTL-to-CMOS level translation. It operates from 4.5 V to 5.5 V, delivers ±4 mA output drive per inverter, exhibits 1.4 V typical hysteresis voltage, and supports industrial temperature range (−55 °C to +125 °C). It is used in clock clean-up, debouncing mechanical switches, and interfacing legacy TTL logic to high-speed CMOS systems.

For engineers reviewing the MC74HCT14AFEL datasheet, pinout, applications, or equivalent options, key selection criteria include its Schmitt-trigger input thresholds (VTmin = 0.5 V, VTmax = 2.1 V), propagation delay ≤48 ns at 125 °C, low quiescent ICC ≤40 µA, and SOEIAJ-14 package compatibility with JEDEC-standard footprint.

Technical Context

The MC74HCT14AFEL integrates six independent Schmitt-trigger inverters in a single monolithic silicon-gate CMOS die. Each channel features asymmetric input hysteresis (VH min = 0.4 V, VH max = 1.5 V) to reject noise on slow-rising/falling signals, enabling reliable operation in electrically noisy environments such as industrial control panels or automotive body electronics.

Its TTL/NMOS-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) allow direct connection to legacy 5 V logic families, while CMOS-compatible outputs (VOH ≥ 4.4 V, VOL ≤ 0.4 V at 4 mA) interface seamlessly with downstream 5 V CMOS, NMOS, or TTL loads-eliminating need for external level-shifting circuitry.

Key Specifications

Pinout & Package

MC74HCT14AFEL is housed in a 14-pin SOEIAJ (Small Outline J-bend) package, also known as JEDEC MS-012 variant, with 1.27 mm pitch, 8.2 mm × 5.45 mm body size, and gull-wing leads. This RoHS-compliant, Pb-free package supports reflow soldering and meets UL 94 V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schmitt-trigger inverter applications.

Compared with SN74HCT14DR and 74HCT14PW,118, the MC74HCT14AFEL offers superior thermal performance in the SOEIAJ package and native compatibility with JEDEC MS-012 footprints used in industrial-grade assemblies-making it optimal for reliability-critical, high-temperature deployments where board real estate is less constrained than thermal margin.

Availability

MC74HCT14AFEL is available at Aetrix Electronics and suitable for industrial control systems, automotive body electronics, and sensor interface modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC74HCT14AFEL 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and logic solutions for automotive, industrial, and cloud infrastructure markets.

The MC74HCT14AFEL belongs to the HCT logic family-designed specifically for TTL-to-CMOS interoperability with guaranteed 5 V operation, industrial temperature tolerance, and Schmitt-trigger noise immunity for robust system-level signal integrity.

FAQ

What is the maximum operating temperature for the MC74HCT14AFEL?

The MC74HCT14AFEL is rated for continuous operation from −55 °C to +125 °C. This full industrial temperature range is validated per JEDEC JESD22-A104 and ensures reliable performance in under-hood automotive environments, motor drives, and outdoor industrial controllers. The SOEIAJ-14 package's thermal resistance (θJA ≈ 140 °C/W) supports this rating when mounted on standard FR-4 PCBs with adequate copper pour.

Does the MC74HCT14AFEL require external pull-up resistors on its inputs?

No, the MC74HCT14AFEL does not require external pull-up resistors on its inputs. Its TTL-compatible input structure has defined VIH (≥2.0 V) and VIL (≤0.8 V) thresholds, and unused inputs must be tied directly to VCC or GND-not left floating-to prevent increased ICC and potential oscillation. Internal input protection diodes and low leakage (<1.0 µA) eliminate need for external biasing in properly terminated circuits.

Can the MC74HCT14AFEL drive a 50 pF capacitive load at 1 MHz?

Yes, the MC74HCT14AFEL can reliably drive a 50 pF load at 1 MHz. AC characterization in the datasheet specifies tPLH/tPHL ≤48 ns and tTLH/tTHL ≤22 ns under CL = 50 pF and 6 ns input edge rates. At 1 MHz (1 µs period), the worst-case propagation delay consumes only ~4.8% of the cycle-leaving ample margin for setup/hold timing. Output drive strength (±4 mA) further ensures stable edge rates into this load.

Is the MC74HCT14AFEL pin-compatible with other 74HCT14 variants?

Yes, the MC74HCT14AFEL is functionally and pinout-compatible with all 74HCT14 variants-including SN74HCT14DR (SOIC-14), 74HCT14PW (TSSOP-14), and MC74HCT14ANG (PDIP-14)-as they share identical logic diagram, pin assignment (14-pin dual-in-line mapping), and electrical behavior. However, package dimensions differ: SOEIAJ-14 (MC74HCT14AFEL) requires its specific footprint and cannot be substituted without PCB revision.

What is the hysteresis voltage specification for the MC74HCT14AFEL at 5.5 V supply?

At VCC = 5.5 V, the MC74HCT14AFEL exhibits a minimum hysteresis voltage (VH min) of 0.4 V and a maximum hysteresis voltage (VH max) of 1.5 V, as specified in the DC Electrical Characteristics table. This 1.1 V span provides consistent noise rejection across the full operating voltage and temperature range, enabling reliable operation even when input signals cross the threshold region slowly or with superimposed noise up to ±0.75 V peak-to-peak.