Texas Instruments CY74FCT2652CTQCT

Overview

CY74FCT2652CTQCT from Texas Instruments is an 8-bit registered transceiver with 3-state outputs, designed for bidirectional bus interfacing in TTL-compatible systems. It features independent A/B registers, real-time/stored data multiplexing, 5.4 ns propagation delay (max), 25-Ω on-chip series output termination, and I_off support for partial-power-down operation in mixed-voltage environments.

For engineers reviewing the CY74FCT2652CTQCT datasheet, CY74FCT2652CTQCT pinout, CY74FCT2652CTQCT application, or CY74FCT2652CTQCT equivalent, this device delivers deterministic timing control, noise-suppressed edge-rate performance, and glitch-free select transitions-critical for high-reliability bus arbitration, memory-mapped I/O expansion, and legacy system upgrades requiring FCT-family compatibility.

Technical Context

The CY74FCT2652CTQCT integrates dual 8-bit D-type flip-flop registers (A and B sides), asynchronous 3-state enable logic (GAB/GBA), and select-control inputs (SAB/SBA) that eliminate multiplexer decoding glitches during real-time ↔ stored data mode transitions. Its architecture supports simultaneous clocking of both registers or staggered loading depending on select-state configuration.

It implements edge-rate control circuitry to limit dV/dt at outputs, matched rise/fall times (<1 ns typical), and 25-Ω integrated series resistors per output to suppress transmission-line reflections. The I_off feature disables outputs and blocks current backflow when V_CC = 0 V, enabling safe hot-insertion and partial power-down in multi-rail systems.

Key Specifications

Pinout & Package

Package: 24-pin QSOP (SSOP-DBQ), 0.154" body width, 0.025" pitch, RoHS-compliant NIPDAU finish, MSL Level-2-260°C-1 year.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY74FCT2652ATQCT, the CY74FCT2652CTQCT offers tighter timing for high-throughput bus cycles; compared with SN74FCT2652CTSO, it provides higher density and improved thermal performance in space-constrained layouts-making CY74FCT2652CTQCT optimal for new surface-mount designs demanding speed and miniaturization.

Availability

CY74FCT2652CTQCT is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, legacy microcontroller I/O expansion, and automated test equipment requiring stable component supply, long-lifecycle support, and guaranteed FCT-family compatibility.

Supply support for CY74FCT2652CTQCT 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, with decades of heritage in high-reliability industrial and automotive IC design.

The CY74FCT2652CTQCT belongs to TI's FCT logic family-engineered for noise-immune, 5-V TTL-compatible bus interfacing in mission-critical systems where signal integrity, timing predictability, and power sequencing safety are non-negotiable.

FAQ

What is the maximum clock frequency supported by CY74FCT2652CTQCT for reliable register operation?

The CY74FCT2652CTQCT does not specify a maximum clock frequency in its datasheet; instead, it defines minimum pulse width (2 ns) and setup/hold times (1.5 ns/5 ns). For reliable operation, the maximum usable clock frequency is determined by the sum of t_su + t_PLH/t_PHL + t_h, yielding ~125 MHz for continuous register loading under worst-case conditions. CY74FCT2652CTQCT is typically deployed in systems with clock rates up to 80 MHz to maintain timing margin.

Does CY74FCT2652CTQCT support hot-swap or live-insertion in powered-backplane systems?

Yes, CY74FCT2652CTQCT supports partial-power-down via its I_off circuitry, which limits current to ±1 µA when V_CC = 0 V while bus lines remain active. This prevents damaging back-current flow during hot-insertion into live 5-V backplanes-provided V_CC ramp-up sequencing follows TI's recommended guidelines. CY74FCT2652CTQCT is qualified for such use in industrial and automotive modules.

Can CY74FCT2652CTQCT operate with 3.3-V input signals while powered at 5 V?

No-CY74FCT2652CTQCT is a 5-V-only device with TTL-compatible input thresholds (V_IH ≥ 2.0 V, V_IL ≤ 0.8 V). While 3.3-V logic outputs may meet V_IH margin, they risk marginal noise immunity and are not guaranteed per datasheet. For mixed-voltage systems, TI recommends level translators or 3.3-V–compatible alternatives like the LVC-series. CY74FCT2652CTQCT requires 5-V input sources for full specification compliance.

How does the "real-time reinforcement" mode work in CY74FCT2652CTQCT when GAB and GBA are both low?

When GAB = GBA = L, CY74FCT2652CTQCT enters real-time reinforcement mode: each output actively drives its corresponding input, maintaining bus state even when other drivers are high-Z. This occurs without clocking or register involvement-data flows directly from A↔B pins. It is used to latch bus states during arbitration pauses. CY74FCT2652CTQCT maintains this behavior regardless of SAB/SBA states, making it ideal for fail-safe hold functions.

Is CY74FCT2652CTQCT pin-compatible with older CY74FCT652T devices?

Yes-CY74FCT2652CTQCT is explicitly documented as function- and pin-compatible with CY74FCT652T, sharing identical pinout, logic behavior, and package dimensions. The key upgrade is integrated 25-Ω output series resistors, which reduce system noise without layout changes. CY74FCT2652CTQCT can directly replace CY74FCT652T in existing designs to improve signal integrity.