onsemi MC74ACT652DW

Overview

MC74ACT652DW from onsemi is an octal registered transceiver with 3-state outputs, non-inverting logic, TTL-compatible inputs, and dual-bus bidirectional data routing via independent A/B registers. It supports real-time or stored-data transfer between 8-bit buses, operates at 4.5–5.5 V, delivers ±24 mA output drive, and uses a 24-pin SOIC (DW) package for industrial bus interface applications.

For engineers reviewing the MC74ACT652DW datasheet, pinout, applications, or equivalent options, this page provides verified functional roles, timing-critical AC/DC specs, register-level control behavior, and direct alternatives for bus isolation, latch-based data multiplexing, and 3-state bus arbitration in legacy TTL- and CMOS-compatible systems.

Technical Context

The MC74ACT652DW implements two independent 8-bit D-type flip-flop registers (A and B), each with dedicated clock (CAB/CBA), select (SAB/SBA), and output-enable (GAB/GBA) controls. Data loads on LOW-to-HIGH clock transitions, enabling synchronized capture from either bus.

Its 3-state outputs support bidirectional bus sharing with isolation capability; real-time transfers occur when SAB/SBA = L/H or H/L, while stored-data transfers require active clocks and matching select states. Propagation delays range from 2.0 ns (tPHL, A→Bn @ 5 V) to 16.5 ns (tPLH, CPAB→An @ 5 V, −40°C to +85°C).

Key Specifications

Pinout & Package

MC74ACT652DW uses a 24-pin SOIC wide-body (SOIC-24 WB) package per case 751E, 300-mil width, Pb-free, with standard 1.27 mm pitch and 7.4–7.6 mm body width (E1). Pin 1 is marked by notch or dot; pin numbering is counterclockwise from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal registered transceiver applications.

Compared with SN74ACT652N and 74ACT652PC, the MC74ACT652DW offers superior thermal performance in surface-mount designs and tighter AC timing for high-speed bus arbitration - making it optimal for space-constrained, thermally demanding, or timing-critical industrial PCBs.

Availability

MC74ACT652DW is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus isolation, programmable logic data paths, and test equipment signal routing requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for MC74ACT652DW 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 MC74ACT652DW belongs to the 74ACT advanced CMOS logic family, designed specifically for high-speed, low-power, TTL-compatible bus interfacing in industrial control, instrumentation, and legacy system upgrades.

FAQ

What is the primary function of the MC74ACT652DW in a digital system?

The MC74ACT652DW serves as an octal registered transceiver that enables bidirectional, clock-synchronized data transfer between two 8-bit buses (A and B). It features independent D-type registers for each bus, 3-state outputs for bus sharing, and TTL-compatible inputs - allowing it to act as a programmable bus interface, data latch, or isolated signal repeater in industrial and legacy computing systems. Its design supports both real-time and stored-data routing modes controlled by SAB/SBA and clocked by CAB/CBA.

Does the MC74ACT652DW support 3.3 V operation?

No, the MC74ACT652DW is specified only for 4.5–5.5 V operation per its Recommended Operating Conditions table. While absolute maximum ratings extend down to −0.5 V, the device does not guarantee correct logic behavior or timing at 3.3 V. For 3.3 V systems, consider the MC74AC652DW (2.0–6.0 V) or dedicated 3.3 V transceivers like the SN74LVC652A. The MC74ACT652DW's TTL-compatible inputs require ≥2.0 V VIH, which is met at 5 V but not reliably at 3.3 V.

How does the MC74ACT652DW handle simultaneous clocking of both A and B registers?

The MC74ACT652DW allows simultaneous LOW-to-HIGH transitions on CAB and CBA to load data from both A and B buses into their respective registers in one cycle - confirmed in the Function Table footnote (**): "Select control = L: clocks can occur simultaneously." This behavior enables atomic capture of paired data sets (e.g., address + command), provided SAB and SBA are held inactive (H) during the clock event to avoid unintended real-time transfers.

What is the significance of the 'DW' suffix in MC74ACT652DW?

The 'DW' suffix denotes a 24-pin SOIC wide-body (SOIC-24 WB) package per onsemi's case outline 751E, with 300-mil width, 1.27 mm lead pitch, and Pb-free construction. It distinguishes the surface-mount version from through-hole alternatives like 'N' (PDIP-24) or 'PC' (plastic DIP-24). The DW package supports automated assembly, offers better thermal performance (JA = 59.8°C/W) than DIP variants, and is used in the MC74ACT652DWR2G tape-and-reel ordering option.

Can the MC74ACT652DW be used as a simple octal buffer without register functionality?

Yes - by holding CAB and CBA permanently HIGH and configuring SAB/SBA for real-time transfer (e.g., SAB=H/SBA=L for A→B), the MC74ACT652DW operates as a non-inverting 3-state octal buffer. However, the internal registers remain transparent in this mode; no latching occurs unless clocks transition. This usage leverages its ±24 mA drive strength and TTL-compatible inputs but bypasses the storage capability - ideal for bus drivers where timing-critical pass-through is needed without added latency.