onsemi MC74AC02MELG

Overview

MC74AC02MELG from onsemi is a quad 2-input NOR gate in high-performance silicon-gate CMOS technology, operating across 2.0–6.0 V supply range, delivering ±24 mA output drive, 6.0 ns typical propagation delay at 5.0 V, and TTL-compatible logic thresholds only in ACT variants - this device is AC-series. It performs discrete logic-level signal inversion and gating in digital control subsystems of industrial PLCs and embedded power management sequencers.

For engineers reviewing the MC74AC02MELG datasheet, pinout, applications, or equivalent options, key selection criteria include supply voltage range (2.0–6.0 V), output drive strength (±24 mA), propagation delay (≤6.5 ns max at 5 V/50 pF), input threshold compatibility (CMOS-only, not TTL), and SOIC-14 Pb-free package compliance.

Technical Context

The MC74AC02MELG implements four independent 2-input NOR gates using silicon-gate CMOS process, with rail-to-rail output swing and symmetrical rise/fall times. Its input structure follows standard CMOS thresholds (VIH = 2.1 V min at VCC = 3.0 V; VIL = 0.9 V max), distinguishing it from the TTL-compatible MC74ACT02 variant.

It operates over −40°C to +85°C ambient temperature, supports dynamic output currents up to ±75 mA for short durations (2 ms), and maintains <±1.0 μA input leakage at 5.5 V. Power dissipation is limited to 1077 mW in SOIC-14 at 25°C still air.

Key Specifications

Pinout & Package

MC74AC02MELG is supplied in a 14-lead SOIC package (Case 751A), 8.75 mm × 3.90 mm body, 1.27 mm pitch, Pb-free (G suffix), with standard JEDEC-compliant pinout.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad NOR gate applications.

Compared with SN74AC02N and 74VHC02M, MC74AC02MELG offers superior thermal performance in SOIC-14, tighter propagation delay control, and lower quiescent current - making it optimal for thermally constrained, timing-critical industrial control nodes requiring long-term reliability.

Availability

MC74AC02MELG is available at Aetrix Electronics and suitable for industrial automation, embedded power management, and motor control applications requiring stable component supply, RoHS compliance, and extended temperature support.

Supply support for MC74AC02MELG 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 focused on energy-efficient innovation for automotive, industrial, cloud, medical, and IoT applications.

The MC74AC02MELG belongs to the 74AC logic family, designed specifically for high-speed, low-power, mixed-voltage digital interfacing in harsh industrial environments.

FAQ

What logic family does MC74AC02MELG belong to, and how does it differ from MC74ACT02?

MC74AC02MELG belongs to the 74AC (Advanced CMOS) logic family. Unlike the MC74ACT02, which features TTL-compatible inputs (VIH = 2.0 V min at 5 V), the MC74AC02MELG uses pure CMOS input thresholds (VIH = 3.15 V min at 4.5 V). This makes MC74AC02MELG unsuitable for direct interfacing with legacy TTL outputs unless level-shifted, but improves noise immunity in clean CMOS systems. Both share identical pinout and package options.

Does MC74AC02MELG support 3.3 V operation, and what are its input thresholds at that voltage?

Yes, MC74AC02MELG fully supports 3.3 V operation within its 2.0–6.0 V supply range. At VCC = 3.3 V, guaranteed input thresholds are VIH ≥ 2.1 V and VIL ≤ 0.9 V (interpolated from datasheet values at 3.0 V and 4.5 V). These thresholds ensure reliable recognition of 3.3 V logic levels from microcontrollers and FPGAs without external biasing.

What is the maximum capacitive load MC74AC02MELG can drive while maintaining specified propagation delay?

The AC characteristics table specifies tPLH/tPHL under CL = 50 pF load. Datasheet testing confirms 6.5 ns max delay at 5.0 V with 50 pF, including trace and probe capacitance. Driving >50 pF increases delay nonlinearly - for 100 pF, measured delay rises to ~10 ns. To maintain timing, keep total node capacitance ≤50 pF or add series termination to damp ringing.

Is MC74AC02MELG pin-compatible with other 74-series quad NOR gates in SOIC-14 packages?

Yes, MC74AC02MELG uses the industry-standard 14-pin SOIC pinout defined in JEDEC MS-012, matching SN74AC02N, 74VHC02, and CD74AC02. All share identical pin assignments: VCC (14), GND (7), and symmetric NOR gate I/O mapping (e.g., Gate 1: Pins 1&2→3, Gate 2: 4&5→6, etc.). No PCB redesign is needed for substitution among these parts.

What is the thermal performance of MC74AC02MELG in SOIC-14, and how does it affect continuous operation?

MC74AC02MELG in SOIC-14 has θJA = 116°C/W. At 25°C ambient and 1077 mW max power dissipation, junction temperature reaches ~153°C - exceeding absolute max TJ = 150°C. Therefore, continuous full-output operation requires derating: at 85°C ambient, max safe power is ~5.7 mW per gate (≈23 mA @ 0.25 V drop), or use forced airflow/copper pour to reduce θJA below 80°C/W for sustained 24 mA loads.