Texas Instruments CD74HC652EN

Overview

CD74HC652EN from Texas Instruments is a high-speed CMOS octal-bus transceiver/register with non-inverting three-state outputs, independent A/B bus registers, and real-time/stored data selection. It operates from 2V to 6V, delivers 12ns typical propagation delay at 5V/15pF, and supports -55°C to +125°C industrial/military temperature range for bidirectional data routing in bus-hold or registered transfer applications.

For engineers reviewing the CD74HC652EN datasheet, CD74HC652EN pinout, CD74HC652EN application, or CD74HC652EN equivalent, key selection criteria include its dual-clock edge-triggered D-type flip-flops, simultaneous OEAB/OEBA control for bus isolation, SAB/SBA-selectable real-time vs. stored data paths, and PDIP-24 package compatibility with legacy LSTTL systems requiring low-power CMOS timing integrity.

Technical Context

The CD74HC652EN integrates two independent octal D-type flip-flop banks (A and B), dual clock inputs (CAB, CBA), and dual select controls (SAB, SBA) to enable four distinct bus management modes: real-time bidirectional transfer, stored-data bidirectional transfer, A-to-B register load with B hold, and B-to-A register load with A hold. Its logic eliminates multiplexer decoding glitches during mode transitions via synchronous select control.

All I/O pins support three-state output control via OEAB (A→B enable) and OEBA (B→A enable), while input leakage remains ≤±1µA over full temperature range. The device uses silicon-gate CMOS technology to achieve LSTTL-compatible speed (up to 60MHz at 5V/15pF) with CMOS power efficiency (ICC ≤160µA max at 125°C).

Key Specifications

Pinout & Package

CD74HC652EN is supplied in a 24-lead plastic dual in-line package (PDIP) with 0.3-inch body width and standard through-hole mounting. Pin 12 is GND; Pin 24 is VCC. Thermal resistance θJA is 67°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT652N and 74LVX652M, CD74HC652EN uniquely balances 2V–6V operation, -55°C to +125°C qualification, and 12ns timing - making it the sole option for legacy 5V industrial controllers needing drop-in CMOS upgrades with full environmental compliance.

Availability

CD74HC652EN is available at Aetrix Electronics and suitable for industrial PLC backplanes, military avionics data buses, and automotive engine control units requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD74HC652EN 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 specializing in analog, embedded processing, and logic solutions for industrial, automotive, and aerospace markets.

The CD74HC652EN belongs to TI's High-Speed CMOS Logic family, designed specifically for robust, low-power bus interfacing in harsh-environment systems where reliability across extreme temperatures and voltage variations is mandatory.

FAQ

What is the maximum operating frequency of CD74HC652EN at 5V supply?

The CD74HC652EN supports a maximum clock frequency of 60MHz when VCC = 5V and load capacitance CL = 15pF, as specified in the switching characteristics table. This value reflects real-time data transfer performance; registered transfer (clocked mode) is limited to 23MHz at the same conditions due to added flip-flop propagation delay. Always verify timing margins against actual board-level CL and signal integrity.

Does CD74HC652EN support true bidirectional data flow without external direction control?

Yes, CD74HC652EN enables true bidirectional data flow using independent OEAB and OEBA controls - OEAB LOW enables A→B transfer while OEBA LOW enables B→A transfer. Both can be active simultaneously for bidirectional real-time exchange, or selectively enabled for unidirectional isolation. No external direction line is needed, unlike basic transceivers.

How does the SAB/SBA pin configuration affect data routing in CD74HC652EN?

In CD74HC652EN, SAB = LOW selects real-time A→B transfer; SAB = HIGH selects stored A→B transfer from internal D flip-flops. Similarly, SBA = LOW enables real-time B→A; SBA = HIGH enables stored B→A. When both are LOW, full bidirectional real-time transfer occurs; when both are HIGH, stored-data bidirectional transfer occurs - all without glitches due to synchronous select logic.

Can CD74HC652EN operate reliably at -55°C ambient temperature?

Yes, CD74HC652EN is fully characterized and guaranteed to operate across -55°C to +125°C, as confirmed in the Absolute Maximum Ratings and Operating Conditions tables. All DC and AC specifications - including VIH/VIL thresholds, propagation delays, and three-state leakage - are validated over this full range, making it suitable for space, defense, and downhole industrial applications.

What is the purpose of simultaneous OEAB and OEBA assertion in CD74HC652EN?

Asserting both OEAB and OEBA LOW in CD74HC652EN configures the device for bus-hold mode: each bus (A and B) reinforces its own signal state. When all other drivers on the bus are high-impedance, this prevents floating lines and maintains last-valid data - critical for power-loss recovery and hot-swap scenarios. This behavior is explicitly documented in the Functional Diagram notes.