Texas Instruments CY74FCT245ATSOC

Overview

CY74FCT245ATSOC from Texas Instruments is an 8-bit noninverting bidirectional transceiver with 3-state outputs, designed for bus-oriented data routing between TTL-compatible systems. It features 64-mA sink / 32-mA source drive strength, 4.6 ns max propagation delay (tPLH/tPHL), Ioff partial-power-down support, and edge-rate control for noise suppression. It operates across –40°C to +85°C in SOIC-20 package and is used in industrial backplane interfaces and legacy system bus isolation.

For engineers reviewing the CY74FCT245ATSOC datasheet, CY74FCT245ATSOC pinout, CY74FCT245ATSOC application, or CY74FCT245ATSOC equivalent, key selection criteria include its 5-V supply compatibility, direction-controlled bidirectional flow (T/R input), high-impedance state enable (OE), and guaranteed 3.3-V typical VOH under load - critical for mixed-voltage bus bridging and hot-swap-capable subsystems.

Technical Context

The CY74FCT245ATSOC implements a dual-bus transceiver architecture with independent A↔B data paths controlled by T/R (transmit/receive) and OE (output enable). Its logic is fully TTL-compatible: inputs accept standard TTL thresholds (VIH = 2 V min, VIL = 0.8 V max), and outputs drive TTL loads directly without level-shifting circuitry.

It integrates Ioff circuitry that disables outputs and blocks current backflow when VCC = 0 V, enabling safe partial-power-down operation. Edge-rate control ensures matched rise/fall times (typical 3.5 ns) and significantly reduces simultaneous switching noise - a requirement for EMI-sensitive industrial and telecom backplanes.

Key Specifications

Pinout & Package

Package: SOIC-20 (DW), 7.5 mm × 12.8 mm body, 1.27 mm pitch, 2.65 mm max height, RoHS-compliant NIPDAU lead finish, MSL Level-1 (unlimited reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74FCT245ATPWR and 74ACT245SCX, the CY74FCT245ATSOC offers optimal balance of industrial temperature range, proven Ioff safety, SOIC-20 manufacturability, and native TTL interoperability - making it the preferred choice for reliability-critical legacy upgrades and backplane interfaces.

Availability

CY74FCT245ATSOC is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus isolation, memory expansion bridges, and test equipment signal routing requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY74FCT245ATSOC 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 experience in industrial-grade interface ICs.

The CY74FCT245ATSOC belongs to TI's FCT logic family, engineered specifically for robust, noise-immune bus interfacing in harsh industrial and telecom environments where reliability, ESD resilience, and mixed-voltage compatibility are mandatory.

FAQ

What is the maximum operating frequency supported by the CY74FCT245ATSOC?

The CY74FCT245ATSOC does not specify a maximum clock frequency in its datasheet because it is a combinatorial transceiver, not a clocked device. Its usable data rate depends on propagation delay (4.6 ns max) and system timing margins. In practice, it reliably supports bus cycles up to ~100 MHz in well-designed layouts with controlled impedance and proper termination - verified by TI's switching characteristics under 50-pF load conditions.

Does the CY74FCT245ATSOC support hot-swap operation?

Yes, the CY74FCT245ATSOC supports hot-swap operation through its Ioff circuitry, which disables outputs and limits reverse current to ±1 µA when VCC = 0 V. This feature is explicitly tested and guaranteed per JESD78, enabling safe insertion/removal in powered-backplane systems - a key design requirement confirmed in the datasheet's "Partial-Power-Down Mode Operation" section.

Can the CY74FCT245ATSOC interface directly between 5-V and 3.3-V systems?

The CY74FCT245ATSOC operates from a 5-V supply and provides TTL-compatible outputs (VOH ≈ 3.3 V typ), making it suitable for driving 3.3-V inputs with adequate noise margin. However, its inputs require ≥2 V for logic high - so 3.3-V outputs can safely drive it. It is not a bidirectional level shifter; for true 3.3-V-to-5-V translation with output protection, a dedicated level translator is recommended alongside the CY74FCT245ATSOC.

What is the purpose of the edge-rate control in the CY74FCT245ATSOC?

The edge-rate control in the CY74FCT245ATSOC limits the slew rate of output transitions to reduce simultaneous switching noise (SSN) and electromagnetic interference (EMI). This is achieved via internal circuitry that shapes rise/fall times to ~3.5 ns (typical), preventing excessive di/dt spikes that could corrupt adjacent signals - a documented feature critical for high-density industrial PCBs and compliance with CISPR 22 Class A emissions limits.

Is the CY74FCT245ATSOC pin-compatible with other FCT245 variants like CY74FCT245CTSOC?

Yes, the CY74FCT245ATSOC is pin-compatible with all CY74FCT245x variants in SOIC-20 (DW) package, including CY74FCT245CTSOC and CY74FCT245TSOC. They share identical pinout, footprint, and function table. The primary difference is propagation delay: 'AT' grade = 4.6 ns max, 'CT' = 4.1 ns, 'T' = 7 ns - all use the same SOIC-20 mechanical interface and electrical pin assignments.