Texas Instruments CY74FCT2541CTQCT

Overview

CY74FCT2541CTQCT from Texas Instruments is an octal noninverting 3-state buffer/line driver with 25-Ω integrated output series resistors, designed for memory address driving, clock distribution, and bus-transceiver applications in 5-V TTL/CMOS systems. It features 4.1 ns max propagation delay, ±15 mA output drive, Ioff partial-power-down support, and ESD protection exceeding 2000-V HBM.

For engineers reviewing the CY74FCT2541CTQCT datasheet, CY74FCT2541CTQCT pinout, CY74FCT2541CTQCT application, or CY74FCT2541CTQCT equivalent, key selection considerations include its 20-pin QSOP (DBQ) package, 25-Ω on-die termination for reflection suppression, matched rise/fall times, and compatibility with both TTL input thresholds and CMOS output levels without external components.

Technical Context

This device implements dual active-low 3-state enable inputs (OEA and OEB) controlling eight noninverting buffered outputs. Its edge-rate control circuitry limits slew rate to reduce simultaneous switching noise, while internal 25-Ω series resistors at each output suppress transmission-line reflections without requiring external termination.

The Ioff feature disables all outputs when VCC = 0 V, preventing backflow current during partial power-down - a critical requirement in hot-swap and mixed-voltage system designs. Input thresholds are TTL-compatible (VIL = 0.8 V, VIH = 2.0 V), and output VOH/VOL specs (3.3 V typ / 0.55 V max) ensure robust interfacing with 5-V CMOS loads.

Key Specifications

Pinout & Package

Package: 20-pin QSOP (SSOP, DBQ), 0.65 mm pitch, 7.4–7.6 mm width, 12.6–13.0 mm length, 2.65 mm max height.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal 3-state buffer applications.

Compared with SN74FCT244DBR and 74ACT244SCX, the CY74FCT2541CTQCT uniquely combines 4.1 ns speed, ±15 mA drive, integrated 25-Ω termination, and Ioff - making it optimal for noise-sensitive, hot-pluggable 5-V bus systems where layout simplicity and power sequencing robustness are design priorities.

Availability

CY74FCT2541CTQCT is available at Aetrix Electronics and suitable for memory subsystems, clock distribution networks, and industrial bus interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for CY74FCT2541CTQCT 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 interface and timing ICs.

The CY74FCT2541CTQCT belongs to TI's FCT logic family, engineered specifically for noise-immune, high-speed 5-V digital interfacing in industrial, communications, and computing equipment where signal integrity and power sequencing resilience are critical.

FAQ

What is the maximum operating frequency supported by the CY74FCT2541CTQCT?

The CY74FCT2541CTQCT has a maximum propagation delay of 4.1 ns (tPLH/tPHL), supporting reliable operation up to approximately 240 MHz in well-terminated 50-pF load conditions. Actual usable frequency depends on board layout, trace length, and termination - the integrated 25-Ω resistors help maintain signal fidelity at these speeds without external components. The CY74FCT2541CTQCT is not characterized for AC parameters above 250 MHz.

Does the CY74FCT2541CTQCT require external pull-up or pull-down resistors on its inputs?

No, the CY74FCT2541CTQCT does not include internal weak pull-ups or pull-downs, and external resistors are not required for normal operation. All inputs are TTL-compatible and must be driven to valid logic levels (VIH ≥ 2.0 V, VIL ≤ 0.8 V); floating inputs are undefined and must be avoided. The CY74FCT2541CTQCT datasheet explicitly states that unused inputs must be tied to VCC or GND to ensure proper function.

Can the CY74FCT2541CTQCT be used in mixed-voltage systems with 3.3-V logic?

The CY74FCT2541CTQCT is specified only for 4.75–5.25 V operation and is not 3.3-V tolerant. Its inputs exceed absolute maximum ratings if exposed to 3.3-V signals without level translation, and its outputs swing to ~3.3 V (typ) - insufficient to reliably drive 3.3-V CMOS inputs requiring VIH ≥ 2.0 V under worst-case conditions. For 3.3-V interfacing, use a dedicated level translator or a 3.3-V logic family; the CY74FCT2541CTQCT is intended strictly for 5-V systems.

How does the Ioff feature of the CY74FCT2541CTQCT protect the device during partial power-down?

The Ioff circuitry in the CY74FCT2541CTQCT disables all output buffers when VCC = 0 V, limiting leakage current to ±1 µA even if outputs are biased to 4.5 V from an active bus. This prevents destructive backflow current through the device during hot-swap or staggered power sequencing - a key requirement in modular backplanes and redundant power architectures. The CY74FCT2541CTQCT remains safe as long as VCC is fully de-energized before applying voltage to I/O pins.

Is the CY74FCT2541CTQCT pin-compatible with the CY74FCT541T?

Yes, the CY74FCT2541CTQCT is functionally and pin-compatible with the CY74FCT541T, sharing identical pinout, logic behavior, and electrical specifications - except the CY74FCT2541CTQCT adds integrated 25-Ω output series resistors and improved noise characteristics via edge-rate control. The CY74FCT2541CTQCT can directly replace the CY74FCT541T in existing designs to reduce reflection noise without PCB changes, provided the 4.1 ns speed grade meets timing requirements.