onsemi MC74HCU04AFELG

Overview

MC74HCU04AFELG from onsemi is a high-performance silicon-gate CMOS hex unbuffered inverter IC, featuring six independent single-stage inverters with 2.0–6.0 V operating voltage range, 10 LSTTL load drive capability, and low input current (±0.1 µA). It is widely used in oscillator circuits, pulse shaping, and high-impedance amplifier applications in industrial control and sensor interface systems.

For engineers reviewing the MC74HCU04AFELG datasheet, pinout, applications, or equivalent options, key selection considerations include its unbuffered inverter architecture, JEDEC-compliant noise immunity, SOIC-14 package compatibility with LS04 and MC14069UB, and suitability for stable RC/crystal oscillator designs across –55°C to +125°C.

Technical Context

The MC74HCU04AFELG implements six identical unbuffered CMOS inverters-each with symmetrical propagation delays (tPLH/tPHL ≤ 18 ns at VCC = 4.5 V) and fast output transition times (tTLH/tTHL ≤ 19 ns). Its input structure supports direct interfacing with CMOS, NMOS, and TTL outputs, and with external pullup resistors, it achieves LSTTL-level compatibility.

This device operates without internal buffering, enabling precise phase control in feedback-based oscillator topologies (e.g., crystal or RC configurations), while maintaining high input impedance (>1 MΩ) and low quiescent ICC (≤40 µA at VCC = 6.0 V), making it ideal for low-power timing and signal conditioning where minimal loading is critical.

Key Specifications

Pinout & Package

MC74HCU04AFELG is packaged in a Pb-free SOIC-14 (Case 751A) with 1.27 mm pitch, 8.75 mm × 3.90 mm body, and standard JEDEC-compliant footprint. Pin 7 is GND; Pin 14 is VCC; each inverter has dedicated input (A1–A6) and output (Y1–Y6) pins arranged symmetrically for minimal trace coupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar unbuffered inverter applications.

Compared with SN74HCU04DR and 74HC04D,653, the MC74HCU04AFELG offers broader temperature support (–55°C to +125°C), AEC-Q100 qualification, and guaranteed unbuffered performance per JEDEC 7.0A - making it the preferred choice for mission-critical timing in automotive and harsh-environment industrial systems.

Availability

MC74HCU04AFELG is available at Aetrix Electronics and suitable for industrial automation controllers, automotive body electronics, and sensor signal conditioning systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC74HCU04AFELG 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, logic, and sensing solutions for automotive, industrial, and cloud infrastructure markets.

The MC74HCU04AFELG belongs to onsemi's high-speed CMOS logic family, designed specifically for precision timing, oscillator stabilization, and noise-immune digital interfacing in demanding embedded environments.

FAQ

What is the maximum operating frequency achievable with MC74HCU04AFELG in a crystal oscillator circuit?

The MC74HCU04AFELG supports crystal oscillator operation up to 20 MHz, as validated in Figure 5 of the official datasheet. Its low propagation delay (18 ns max at 4.5 V) and 10 pF input capacitance ensure stable startup and minimal phase jitter in Pierce configurations with AT-cut fundamental-mode crystals. The MC74HCU04AFELG's unbuffered design avoids added delay that could destabilize high-frequency loops.

Does MC74HCU04AFELG support mixed-voltage interfacing between 3.3 V and 5 V logic domains?

Yes - the MC74HCU04AFELG operates from 2.0 V to 6.0 V and features CMOS-compatible inputs that accept voltages from 0 V to VCC. When powered at 3.3 V, it correctly interprets 5 V-tolerant inputs (with appropriate current limiting) and outputs 0–3.3 V logic levels. For robust 5 V → 3.3 V translation, external resistive dividers or dedicated level shifters are recommended, but the MC74HCU04AFELG itself does not provide inherent 5 V tolerance on inputs.

Can MC74HCU04AFELG replace MC14069UB in existing designs without layout changes?

Yes - the MC74HCU04AFELG is explicitly stated in the datasheet to be identical in pinout to the MC14069UB and LS04. All six inverter inputs (A1–A6) and outputs (Y1–Y6), plus VCC (Pin 14) and GND (Pin 7), match exactly. No PCB modifications are needed; however, verify supply voltage compatibility (MC14069UB supports up to 18 V, while MC74HCU04AFELG is limited to 6.0 V max) before substitution.

What is the significance of the "FELG" suffix in MC74HCU04AFELG?

The "FELG" suffix identifies the MC74HCU04AFELG as a Pb-free, halogen-free SOIC-14 package (Case 751A) manufactured by onsemi. "F" denotes SOIC narrow-body, "E" indicates tape-and-reel packaging, "L" specifies lead-free plating, and "G" confirms RoHS compliance. This matches the ordering code MC74HCU04ADR2G in the datasheet's Ordering Information table, confirming its commercial-grade, surface-mount configuration.

How does MC74HCU04AFELG differ from buffered hex inverters like MC74HC04A?

The MC74HCU04AFELG is unbuffered - each inverter stage consists of a single CMOS inverter pair, resulting in lower propagation delay (18 ns vs. ~23 ns for HC04) and higher input capacitance sensitivity. Buffered versions (e.g., MC74HC04A) add internal gain stages for improved drive strength and noise rejection but introduce additional delay and phase shift. The MC74HCU04AFELG is optimized for oscillator and analog-like applications where minimal delay and predictable phase response are essential.