Texas Instruments CY74FCT245ATPCG4

Overview

CY74FCT245ATPCG4 from Texas Instruments is an 8-bit noninverting bidirectional transceiver with 3-state outputs, designed for bus-oriented data transfer between TTL- and CMOS-compatible systems. It features 64-mA sink / 32-mA source drive strength, 4.6 ns max propagation delay, Ioff partial-power-down support, and edge-rate control for noise reduction. It operates across –40°C to +85°C in a 20-pin PDIP package and is used in industrial control backplanes and legacy system bus interfacing.

For engineers reviewing the CY74FCT245ATPCG4 datasheet, CY74FCT245ATPCG4 pinout, CY74FCT245ATPCG4 application, or CY74FCT245ATPCG4 equivalent, key selection criteria include bidirectional bus isolation capability, TTL-compatible input thresholds, 3-state enable timing (tPZH/tPHZ ≤ 6.2 ns), Ioff leakage (< ±1 µA at VCC = 0 V), and compatibility with FCT logic families.

Technical Context

This device implements dual-directional data flow controlled by an active-high T/R signal and independent 3-state output enable (OE). Its internal architecture includes edge-rate-controlled drivers that limit di/dt to suppress simultaneous switching noise, and Ioff circuitry that disables outputs during power-down to prevent backflow current when VCC = 0 V.

It supports mixed-voltage interfacing: inputs accept TTL-level signals (VIH = 2 V min, VIL = 0.8 V max) while maintaining full 5-V CMOS output swing (VOH = 2.4 V min at IOH = –32 mA, VOL = 0.55 V max at IOL = 64 mA), enabling robust interoperation between legacy and modern logic families.

Key Specifications

Pinout & Package

Package: 20-pin Plastic Dual In-line Package (PDIP), 0.300" wide, RoHS-compliant NiPdAu lead finish, MSL N/A.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY74FCT245ATPCG4, CY74FCT245ATSOCT offers superior thermal performance and SMT manufacturability, while SN74FCT245ATPC provides identical through-hole functionality at broader distribution-both serve as direct functional alternatives without redesign.

Availability

CY74FCT245ATPCG4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, and automotive diagnostic subsystems requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CY74FCT245ATPCG4 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 for industrial, automotive, and communications markets.

CY74FCT245ATPCG4 belongs to the FCT logic family, engineered for high-speed, low-noise bus interfacing in mission-critical industrial and automotive systems where reliability and signal integrity are paramount.

FAQ

What is the maximum operating frequency supported by CY74FCT245ATPCG4?

CY74FCT245ATPCG4 does not specify a maximum clock frequency, as it is a combinatorial transceiver-not a clocked device. Its usable data rate depends on system-level timing margins: with 4.6 ns max propagation delay and 6.2 ns max enable/disable times, it reliably supports asynchronous bus protocols up to ~100 MHz in well-terminated, low-capacitance layouts. Actual throughput is governed by external bus controller timing, not the CY74FCT245ATPCG4 itself.

Does CY74FCT245ATPCG4 support mixed-voltage operation between 3.3 V and 5 V domains?

CY74FCT245ATPCG4 is a 5-V-only device with TTL-compatible inputs (VIH ≥ 2 V, VIL ≤ 0.8 V) and CMOS outputs (VOH ≥ 2.4 V at –32 mA). It does not support 3.3-V supply or I/O directly. To interface with 3.3-V systems, external level-shifting circuitry or a dual-supply transceiver (e.g., TXB0108) is required. The CY74FCT245ATPCG4 itself must be powered from 4.75–5.25 V.

How does the Ioff feature of CY74FCT245ATPCG4 protect the system during partial power-down?

The Ioff circuitry in CY74FCT245ATPCG4 actively disables all outputs when VCC = 0 V, limiting leakage current to ±1 µA even if A or B port pins are driven to 4.5 V. This prevents reverse current flow from live bus traces into unpowered sections of the system-critical for hot-swap backplanes, modular instrumentation, and systems with staggered power sequencing. It eliminates the need for external blocking diodes or isolation switches.

Can CY74FCT245ATPCG4 be used in place of CY54FCT245T in military applications?

No. CY74FCT245ATPCG4 is a commercial-grade part rated for –40°C to +85°C and packaged in RoHS-compliant PDIP. CY54FCT245T is a military-spec device (MIL-PRF-38535) offered in CDIP or LCCC packages, qualified for –55°C to +125°C, and tested to stricter screening standards. While electrically similar, CY74FCT245ATPCG4 lacks the environmental ruggedness, extended temperature range, and qualification testing required for defense/aerospace deployments.

What is the purpose of the edge-rate control circuitry in CY74FCT245ATPCG4?

The edge-rate control circuitry in CY74FCT245ATPCG4 intentionally limits the slew rate of output transitions to reduce simultaneous switching noise (SSN) and electromagnetic interference (EMI). Unlike uncontrolled fast-switching logic, this feature maintains signal integrity on shared buses by suppressing high-frequency harmonics-especially critical in dense PCB layouts with multiple parallel data lines, without sacrificing the 4.6 ns propagation delay needed for high-speed operation.