onsemi MC74AC32N

Overview

MC74AC32N from onsemi is a quad 2-input OR gate in high-performance silicon-gate CMOS technology, operating at 2.0–6.0 V supply voltage, delivering ±24 mA output drive, with propagation delays as low as 5.0 ns (VCC = 5.0 V, CL = 50 pF), and used in digital logic interfacing, bus arbitration, and control signal combining in industrial and embedded systems.

For engineers reviewing the MC74AC32N datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, SOIC-14 package mapping, DC/AC electrical specifications, input/output voltage thresholds, thermal limits, and direct alternatives for logic-level translation and discrete gate replacement scenarios.

Technical Context

The MC74AC32N implements four independent OR logic functions using CMOS transistor pairs with rail-to-rail output swing and TTL-compatible output drive capability. It supports operation across −40°C to +85°C ambient temperature and exhibits input leakage ≤±1.0 µA at 5.5 V.

Its AC performance is characterized at CL = 50 pF with tPLH/tPHL ≤7.5 ns (typical) and ≤8.5 ns (max) at VCC = 5.0 V, while DC parameters include VIH = 2.1 V (min) and VIL = 0.9 V (max) at VCC = 3.0 V, ensuring robust noise margin in mixed-voltage systems.

Key Specifications

Pinout & Package

MC74AC32N is supplied in a 14-lead SOIC package (Case 751A), with 1.27 mm pitch, 8.75 mm × 3.90 mm body, and standard JEDEC-compliant footprint. Pin 1 is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input OR gate applications.

Compared with SN74AC32N and MC74ACT32DG, the MC74AC32N offers optimal noise immunity in 3.3 V–5.0 V hybrid systems due to its scalable VIH/VIL thresholds, while maintaining full pin-and-function compatibility with both alternatives in SOIC-14 layout.

Availability

MC74AC32N is available at Aetrix Electronics and suitable for industrial control logic, microcontroller peripheral interface, legacy system bus arbitration, and power sequencing control requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MC74AC32N 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 MC74AC32N belongs to onsemi's 74AC logic family, designed for high-speed, low-power CMOS applications where robust noise immunity, wide supply range, and TTL-output drive are required in space-constrained industrial and embedded designs.

FAQ

What logic family does MC74AC32N belong to, and how does it differ from 74HC or 74LS variants?

The MC74AC32N belongs to the 74AC (Advanced CMOS) logic family. It differs from 74HC by offering higher output drive (±24 mA vs. ±4–8 mA) and faster propagation (≤8.5 ns vs. ≤15 ns), and from 74LS by using CMOS inputs (high impedance, low power) instead of bipolar TTL inputs. The MC74AC32N maintains full 74AC logic-level compatibility while supporting 2.0–6.0 V operation - unlike 74LS which is strictly 5 V only.

Can MC74AC32N operate reliably at 3.3 V, and what are its input voltage thresholds at that supply?

Yes, MC74AC32N is fully specified for 3.3 V operation. At VCC = 3.0 V, its guaranteed input thresholds are VIH ≥ 2.1 V and VIL ≤ 0.9 V, providing a minimum noise margin of 1.2 V for high-to-low transitions and 0.9 V for low-to-high transitions. These values are confirmed in the DC Characteristics table on page 3 of the official datasheet.

Is MC74AC32N pin-compatible with MC74ACT32DG, and can they be interchanged on the same PCB?

Yes, MC74AC32N and MC74ACT32DG share identical SOIC-14 pinouts and mechanical dimensions (Case 751A), enabling direct PCB substitution. However, their input thresholds differ: MC74AC32N scales VIH/VIL with VCC, while MC74ACT32DG fixes them at 2.0 V/0.8 V for TTL compatibility. Interchange is safe if system-level noise margins and source logic family are verified.

What is the maximum recommended capacitive load for MC74AC32N, and how does load affect its propagation delay?

The MC74AC32N AC characteristics are specified at CL = 50 pF, with tPLH/tPHL ≤8.5 ns (max) at VCC = 5.0 V. While not explicitly rated beyond 50 pF, typical loading up to 75 pF increases delay by ~15–20% based on measured CPD = 20 pF and output drive capability. For loads >100 pF, buffering or reducing trace length is advised to maintain timing integrity in the MC74AC32N design.

Does MC74AC32N require external pull-up or pull-down resistors on unused inputs?

No, MC74AC32N inputs have CMOS structure with negligible leakage (IIN ≤ ±1.0 µA), so unused inputs may be tied directly to VCC or GND without resistors. Floating inputs are strongly discouraged due to increased susceptibility to noise-induced oscillation and elevated ICC. Tying unused inputs to a defined rail ensures predictable logic states and minimal power consumption in the MC74AC32N circuit.