onsemi MC74AC02NG

Overview

MC74AC02NG 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, with propagation delays as low as 4.0 ns at 5.0 V and 50 pF load, used in digital logic interfacing, address decoding, and control signal generation in industrial and embedded systems.

For engineers reviewing the MC74AC02NG datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, SOIC-14 package mapping, confirmed DC/AC electrical parameters, real-world use scenarios, and two validated alternative parts for logic-level compatibility and supply voltage matching.

Technical Context

The MC74AC02NG implements four independent 2-input NOR gates using advanced CMOS process, supporting rail-to-rail input voltage range (0 to VCC) and TTL-compatible output swing. Its logic threshold is defined by VIL = 0.9 V and VIH = 2.1 V at VCC = 3.0 V, ensuring robust noise immunity in mixed-voltage systems.

It operates over −40°C to +85°C ambient temperature, features 4.5 pF typical input capacitance and 30 pF power dissipation capacitance, and meets JEDEC JESD78 latch-up immunity (>100 mA), making it suitable for stable operation in noise-prone industrial control environments.

Key Specifications

Pinout & Package

MC74AC02NG is supplied in a Pb-free SOIC-14 (Case 751A) package, 8.75 mm × 4.00 mm body size, 1.27 mm pitch, with standard gull-wing leads for reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AC02N and 74VHC02N, MC74AC02NG uniquely balances industrial temperature rating, 4.0 ns speed, and ±24 mA drive in a single Pb-free SOIC-14 package - making it optimal for ruggedized embedded control where reliability and timing coexist.

Availability

MC74AC02NG is available at Aetrix Electronics and suitable for industrial control logic, microcontroller peripheral interface, power sequencing control, and legacy system bus glue logic requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MC74AC02NG 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 electronics, serving automotive, industrial, cloud, and IoT markets with discrete, analog, and logic solutions.

The MC74AC02NG belongs to the 74AC logic family - designed specifically for high-speed, low-power CMOS replacement of legacy TTL in industrial and embedded systems requiring wide supply voltage range and robust ESD/latch-up performance.

FAQ

What logic family does MC74AC02NG belong to, and how does it differ from 74ACT variants?

The MC74AC02NG belongs to the 74AC (Advanced CMOS) logic family, characterized by CMOS inputs and outputs with rail-to-rail voltage thresholds. Unlike the 74ACT variant (e.g., MC74ACT02), which features TTL-compatible inputs (VIH = 2.0 V fixed), the MC74AC02NG uses CMOS-compatible thresholds that scale with VCC - e.g., VIH = 2.1 V at 3.0 V and 3.85 V at 5.5 V. This makes MC74AC02NG ideal for mixed-supply systems where input levels vary, while MC74ACT02 suits legacy TTL-driven designs.

Can MC74AC02NG operate reliably at 3.3 V, and what are its key timing parameters at that voltage?

Yes, MC74AC02NG is fully specified for 3.3 V operation (2.0–6.0 V range). At VCC = 3.3 V and CL = 50 pF, its typical propagation delay is 5.0 ns (tPLH/tPHL), with guaranteed maximum of 7.5 ns over −40°C to +85°C. Input thresholds are VIH = 1.5 V (min) and VIL = 0.9 V (max), ensuring compatibility with 3.3 V LVTTL and LVCMOS outputs. The device maintains ±24 mA drive strength and 4.5 pF input capacitance at this voltage.

Is MC74AC02NG pin-compatible with other 14-pin quad NOR gate packages like SN74LS02 or CD4002?

No, MC74AC02NG is not pin-compatible with SN74LS02 (TTL) or CD4002 (CMOS), despite sharing the same SOIC-14 physical package. Pin assignments differ: MC74AC02NG uses Pins 1&2 → Gate 1 inputs, Pin 3 → Gate 1 output; SN74LS02 uses Pins 1&2 → Gate 1 inputs, Pin 3 → Gate 1 output (same), but CD4002 assigns Gate 1 to Pins 2&3 with output on Pin 4. Always verify pin mapping against the MC74AC02NG datasheet - do not assume mechanical compatibility implies functional or electrical interchangeability.

What is the maximum capacitive load MC74AC02NG can drive while maintaining specified timing?

MC74AC02NG is characterized for CL = 50 pF, with propagation delays guaranteed up to that load. While it can drive higher capacitance (e.g., 100 pF), timing degrades linearly - tPLH/tPHL increases ~1.5 ns per additional 10 pF beyond 50 pF. For loads exceeding 75 pF, consider adding a buffer stage or selecting a higher-drive variant. The 24 mA output capability ensures stable edge rates into typical PCB traces and moderate fan-out, but layout-dependent parasitics must be minimized to preserve the 4.0 ns (typ) performance.

Does MC74AC02NG require external pull-up or pull-down resistors on unused inputs?

Yes - unused inputs on MC74AC02NG must be terminated to VCC or GND to prevent floating nodes, which cause increased ICC, noise susceptibility, and potential oscillation. Because the NOR gate output is active-low, tying an unused input to VCC forces the corresponding output low; tying to GND leaves the output controlled only by the other input. A 10 kΩ resistor to VCC or GND is recommended. Leaving inputs unconnected violates the Absolute Maximum Ratings (VI limits) and risks erratic behavior, especially at temperature extremes.