Texas Instruments CD74ACT651M96

Overview

CD74ACT651M96 from Texas Instruments is a high-speed CMOS octal bus transceiver with 3-state outputs and non-inverting data paths, operating at 4.5–5.5 V supply, with propagation delay of 8.5 ns typical at 5 V and ±24 mA output drive capability. It serves as bidirectional data interface in microprocessor address/data bus isolation and memory expansion systems.

For engineers reviewing the CD74ACT651M96 datasheet, CD74ACT651M96 pinout, CD74ACT651M96 application, or CD74ACT651M96 equivalent, key selection considerations include its TTL-compatible input thresholds, symmetric output drive strength, 24-pin SOIC (DW) package, -55°C to +125°C operating range, and compatibility with ACT logic family timing and noise margins.

Technical Context

This device implements dual 4-bit bidirectional transceivers with separate control for direction (DIR) and output enable (OE) on each half, enabling independent flow control across two 4-bit data channels. Its ACT logic family ensures 5-V TTL-level compatibility while maintaining CMOS power efficiency and noise immunity.

The CD74ACT651M96 features balanced rise/fall times (typ. 7.5 ns), guaranteed AC/DC parametric performance over full military temperature range, and bus-hold circuitry on all inputs to eliminate external pull-ups in floating-bus applications.

Key Specifications

Pinout & Package

CD74ACT651M96 is housed in a 24-pin SOIC (DW) package with 300-mil body width, gull-wing leads, and RoHS-compliant NiPdAu finish. Pin 1 orientation follows Q1 quadrant per TI tape-and-reel specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT245N and CD74ACT652M96, the CD74ACT651M96 uniquely supports independent 4-bit channel control and preserves data polarity-critical for modular bus architectures requiring granular flow arbitration and signal integrity across split data paths.

Availability

CD74ACT651M96 is available at Aetrix Electronics and suitable for microprocessor bus isolation, memory expansion interfaces, industrial backplane interconnects, and legacy system data bridges requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for CD74ACT651M96 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

Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and logic solutions with emphasis on reliability, longevity, and industrial-grade qualification.

The CD74ACT651M96 belongs to TI's Advanced CMOS (ACT) logic family, engineered for high-noise-immunity, TTL-compatible 5-V digital interfacing in mission-critical military, aerospace, and industrial control systems.

FAQ

What is the function of the DIR and OE pins on CD74ACT651M96?

The CD74ACT651M96 uses DIR (direction) and OE (output enable) pins to control data flow per 4-bit channel. DIR determines whether data passes from A to B or B to A; OE disables all outputs to high-impedance state. Both signals are active-high and operate independently for each half of the device, enabling flexible bus arbitration in complex systems where CD74ACT651M96 is deployed.

Does CD74ACT651M96 support operation at 3.3 V?

No, CD74ACT651M96 is specified only for 4.5 V to 5.5 V supply operation. Its TTL-compatible input thresholds and ACT-family design require nominal 5-V rails. Attempting 3.3-V operation results in undefined logic thresholds, degraded noise margins, and potential failure to meet AC timing specs. For 3.3-V systems, consider TI's LVC or AUC logic families instead of CD74ACT651M96.

Is CD74ACT651M96 pin-compatible with CD74ACT652M96?

Yes, CD74ACT651M96 and CD74ACT652M96 share identical 24-pin SOIC (DW) package, pin assignments, and control signal mapping. The sole functional difference is data polarity: CD74ACT651M96 is non-inverting, while CD74ACT652M96 inverts data on both channels. No PCB changes are needed when substituting, but system-level logic must account for the inversion introduced by CD74ACT652M96 versus CD74ACT651M96.

What does "bus-hold" mean for CD74ACT651M96 inputs?

Bus-hold circuitry in CD74ACT651M96 actively retains the last valid logic state on each input pin when driven to high-impedance, eliminating floating nodes without external pull-up or pull-down resistors. This feature reduces component count, improves noise immunity during bus contention, and prevents spurious transitions during power-up or hot-swap events - a key reliability advantage in systems using CD74ACT651M96 for critical interconnects.

What is the maximum clock frequency supported by CD74ACT651M96 in a data bus application?

CD74ACT651M96 does not operate on a clock signal - it is an asynchronous transceiver. Its usable data rate depends on propagation delay (8.5 ns max) and system timing margins. In practice, CD74ACT651M96 reliably supports bus handshaking up to ~100 MHz in well-designed layouts with controlled impedance and proper termination. The actual maximum frequency in any given application must be validated against setup/hold timing of connected devices, not derived from CD74ACT651M96 alone.