onsemi MC74ACT652DWG

Overview

MC74ACT652DWG from onsemi is an octal registered bus transceiver with 3-state non-inverting outputs, designed for bidirectional data flow between A and B buses in high-speed digital systems. It features independent A/B registers, real-time and stored-data multiplexing, TTL-compatible inputs, ±24 mA output drive, and operates at 4.5–5.5 V supply. It is used in address/data bus isolation and register-controlled data routing in industrial control backplanes.

For engineers reviewing the MC74ACT652DWG datasheet, pinout, applications, or equivalent options, key selection criteria include clock-controlled register loading (CAB/CBA), dual-direction 3-state enable (GAB/GBA), transmit/receive select (SAB/SBA), propagation delay ≤16.5 ns at 5 V, and SOIC-24 package compatibility with legacy 74ACT logic families.

Technical Context

The MC74ACT652DWG implements two independent 8-bit D-type flip-flop registers-one per bus-synchronized to LOW-to-HIGH transitions on CAB (load A bus → register) and CBA (load B bus → register). Its control logic supports four distinct data-handling modes: real-time A→B or B→A transfer, register-to-bus output, and simultaneous register load from either bus.

Each direction uses dedicated 3-state output enables (GAB for A→B outputs, GBA for B→A outputs) and directional select inputs (SAB for A→B path selection, SBA for B→A path selection). All inputs are TTL-compatible (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V), ensuring interoperability with standard 5 V logic families.

Key Specifications

Pinout & Package

MC74ACT652DWG is housed in a 24-pin SOIC (Small Outline Integrated Circuit) package, case 751E, 300-mil width, Pb-free, with standard JEDEC-compliant dimensions (D = 15.25–15.54 mm, E1 = 7.40–7.60 mm, e = 1.27 mm pitch).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC74ACT652DWG, SN74ACT652N offers identical logic functionality but inferior thermal performance and larger footprint, while 74LVTH16652DGGR delivers higher speed and density at the cost of 5 V incompatibility and doubled pin count - making MC74ACT652DWG the optimal choice for cost-sensitive, mixed-voltage industrial upgrades.

Availability

MC74ACT652DWG is available at Aetrix Electronics and suitable for industrial backplane isolation, microcontroller I/O expansion, test equipment signal routing, and legacy bus bridging requiring stable component supply and long-term obsolescence management.

Supply support for MC74ACT652DWG 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 silicon solutions for automotive, industrial, cloud computing, and IoT applications.

The MC74ACT652DWG belongs to the 74ACT advanced CMOS logic family, engineered for high-speed, low-power, TTL-compatible operation in industrial control and instrumentation systems where reliability and pin-for-pin upgrade paths matter.

FAQ

What is the maximum operating frequency supported by the MC74ACT652DWG?

The MC74ACT652DWG does not specify a maximum clock frequency directly, but its worst-case propagation delay is 16.5 ns (at VCC = 5.0 V, TA = −40°C to +85°C, CL = 50 pF). This supports reliable operation in bus systems with cycle times ≥33 ns, corresponding to a practical upper limit of approximately 30 MHz for synchronous register-to-bus transfers. Real-time pass-through operation may achieve higher effective throughput depending on system-level timing margins.

Does the MC74ACT652DWG support simultaneous loading of both A and B registers?

Yes, the MC74ACT652DWG supports simultaneous register loading: when both CAB and CBA receive LOW-to-HIGH transitions in the same clock cycle, data from A0–A7 and B0–B7 is latched into their respective registers concurrently. The function table confirms this behavior under "Store A and B Data" (GAB = L, GBA = H, CAB = ⇑, CBA = ⇑), enabling atomic snapshot capture of bidirectional bus states.

Can the MC74ACT652DWG be used with a 3.3 V supply?

No, the MC74ACT652DWG is not rated for 3.3 V operation. Its recommended VCC range is strictly 4.5–5.5 V, and absolute maximum ratings prohibit operation below 4.5 V. Using 3.3 V will result in undefined logic levels, excessive propagation delay, and potential failure to meet VIH/VIL thresholds. For 3.3 V systems, consider the 74LVT or 74LVTH families instead.

How does the MC74ACT652DWG handle bus contention during direction switching?

The MC74ACT652DWG prevents bus contention via independent 3-state enables: GAB controls B0–B7 drivers, GBA controls A0–A7 drivers. To avoid conflict, designers must ensure one side is disabled (GAB or GBA = HIGH) before enabling the opposite direction. The fast output disable time (tPLZ/tPHZ ≤14 ns) minimizes overlap, but proper sequencing in firmware or control logic remains essential for robust operation.

Is the MC74ACT652DWG pin-compatible with the MC74AC652DWG?

Yes, the MC74ACT652DWG is pin-compatible and functionally identical to the MC74AC652DWG in the same SOIC-24 package, differing only in input threshold specifications: MC74ACT652DWG has TTL-compatible inputs (VIH = 2.0 V min), while MC74AC652DWG uses CMOS thresholds (VIH = 3.15 V min at VCC = 4.5 V). This makes MC74ACT652DWG a direct drop-in replacement where interfacing with TTL or microcontroller GPIOs is required.