Texas Instruments CY74FCT540CTQCTE4

Overview

CY74FCT540CTQCTE4 from Texas Instruments is an 8-bit inverting buffer/line driver with 3-state outputs, designed for memory address and clock distribution, bus transceivers, and TTL/CMOS interface applications. It delivers 4.1 ns propagation delay (max), ±32 mA output source/sink capability, and operates across –40°C to +85°C with 4.75 V–5.25 V supply. Its Ioff circuitry enables partial-power-down mode in mixed-voltage systems.

For engineers reviewing the CY74FCT540CTQCTE4 datasheet, CY74FCT540CTQCTE4 pinout, CY74FCT540CTQCTE4 application, or CY74FCT540CTQCTE4 equivalent, key selection criteria include 3-state enable timing (tPZH/tPLZ ≤ 5.8 ns), matched rise/fall times, edge-rate control for noise suppression, and compatibility with TTL input thresholds and 3.3 V–5 V logic levels.

Technical Context

This device implements dual active-low 3-state output enables (OEA and OEB) controlling eight inverting buffered channels. Each channel features TTL-compatible inputs, CMOS-level outputs, and independent edge-rate control circuitry that reduces simultaneous switching noise without external components.

The Ioff specification (±1 µA at VCC = 0 V, VOUT = 4.5 V) ensures safe back-drive immunity during partial power-down, while matched tPLH/tPHL (1.5–4.1 ns) and tPZH/tPLZ (1.5–5.8 ns) support high-speed synchronous bus operation in industrial and embedded control systems.

Key Specifications

Pinout & Package

Package: 20-pin SSOP (DBQ), 0.209" body width, 0.025" pitch, RoHS-compliant NiPdAu lead finish, MSL Level-2-260°C-1 year.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit inverting 3-state buffer applications.

Compared with SN74FCT540CTQCT and 74ACT540SCX, CY74FCT540CTQCTE4 uniquely combines industrial temperature range, Ioff-enabled power sequencing, and 4.1 ns performance in a drop-in SSOP package-making it the sole option for robust, mixed-rail embedded bus interfaces.

Availability

CY74FCT540CTQCTE4 is available at Aetrix Electronics and suitable for industrial automation, embedded instrumentation, and legacy bus interface applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for CY74FCT540CTQCTE4 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 connectivity solutions with emphasis on reliability, longevity, and industrial-grade qualification.

CY74FCT540CTQCTE4 belongs to the FCT logic family, engineered for high-speed, low-noise, mixed-voltage system interfacing in industrial control, test equipment, and military/aerospace subsystems.

FAQ

What is the maximum operating temperature range for CY74FCT540CTQCTE4?

CY74FCT540CTQCTE4 is specified for continuous operation from –40°C to +85°C ambient temperature. This industrial temperature grade supports deployment in harsh environments such as factory-floor PLCs, motor drives, and outdoor telemetry units where thermal cycling and extended uptime are critical. The device maintains full electrical performance-including 4.1 ns propagation delay and 32 mA output drive-across this entire range.

Does CY74FCT540CTQCTE4 support partial-power-down operation?

Yes, CY74FCT540CTQCTE4 includes Ioff circuitry that limits current to ±1 µA when VCC = 0 V and outputs are biased to 4.5 V. This feature enables safe insertion/removal in live backplanes and allows selective powering of subsystems without risking back-drive damage to unpowered ICs-critical in modular industrial controllers and hot-swappable I/O modules using CY74FCT540CTQCTE4 as a bus isolator.

What is the pin compatibility status of CY74FCT540CTQCTE4 with CY54FCT540T devices?

CY74FCT540CTQCTE4 shares identical pinout and logic function with CY54FCT540T variants (e.g., CY54FCT540CTLMB), but differs in temperature rating (–40°C to +85°C vs –55°C to +125°C) and package (SSOP vs LCC/CDIP). While electrically and functionally compatible, mechanical mounting and thermal design must account for the SSOP footprint and 68°C/W θJA. No PCB redesign is needed if replacing CY74FCT540CTQCTE4 with another Q-packaged FCT540 variant.

How does the edge-rate control in CY74FCT540CTQCTE4 reduce system noise?

CY74FCT540CTQCTE4 integrates on-die edge-rate control that limits output slew rate without external resistors. This reduces di/dt-induced ground bounce and crosstalk on densely routed PCBs-especially beneficial in clock distribution networks and parallel data buses where simultaneous switching of multiple outputs would otherwise generate >100 mV noise spikes. Measured noise reduction exceeds 40% versus standard FCT buffers under identical 50 pF load conditions.

Can CY74FCT540CTQCTE4 directly interface with 3.3 V CMOS logic?

Yes, CY74FCT540CTQCTE4 outputs deliver VOH = 3.3 V (typical) at –32 mA load, meeting the VIH requirement of standard 3.3 V CMOS devices (VIH ≥ 2.0 V). Its TTL-compatible inputs (VIH = 2.0 V min) also accept 3.3 V logic highs directly. This eliminates level-shifters in mixed-voltage systems-enabling seamless integration of CY74FCT540CTQCTE4 between 5 V microcontrollers and 3.3 V peripherals like ADCs or flash memory.