Texas Instruments CY74FCT245CTQCT

Overview

CY74FCT245CTQCT from Texas Instruments is an 8-bit noninverting bidirectional transceiver with 3-state outputs, designed for bus-oriented data transfer between two TTL-compatible logic domains. It features 64-mA sink / 32-mA source drive strength, 4.1-ns max propagation delay (tPLH/tPHL), Ioff partial-power-down support, and edge-rate controlled outputs for noise reduction. It operates across –40°C to 85°C in QSOP-20 package and is used in industrial control backplanes and legacy system bus isolation.

For engineers reviewing the CY74FCT245CTQCT datasheet, CY74FCT245CTQCT pinout, CY74FCT245CTQCT application, or CY74FCT245CTQCT equivalent, key selection criteria include bidirectional direction control via T/R input, simultaneous 3-state enable via OE, guaranteed 5-V TTL compatibility, and validated Ioff behavior at VCC = 0 V for hot-swap safety.

Technical Context

The CY74FCT245CTQCT implements dual-bus bidirectional buffering using a single transmit/receive (T/R) control line to determine data flow direction (A→B or B→A), while output enable (OE) independently places both A and B ports into high-impedance state. Its FCT-family architecture ensures function, pinout, and drive compatibility with industry-standard FCT and F logic families.

Edge-rate control circuitry limits slew rate to suppress switching noise, and the Ioff feature actively disables outputs when VCC = 0 V, preventing current backflow during partial power-down sequences. Input thresholds (VIH = 2 V min, VIL = 0.8 V max) and output levels (VOH = 2.4 V min at –32 mA, VOL = 0.55 V max at 64 mA) are fully specified for 5-V TTL interfacing.

Key Specifications

Pinout & Package

Package: QSOP-20 (DBQ), 0.64 mm pitch, 7.2 mm × 5.3 mm body, 1.2 mm max height, 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 bidirectional bus transceiver applications.

Compared with SN74FCT245CTSOCT and 74ACT245SCX, CY74FCT245CTQCT uniquely balances compact QSOP packaging, robust 64-mA drive, Ioff-enabled hot-swap safety, and proven FCT interoperability - making it optimal for space-constrained industrial bus nodes requiring reliability under dynamic power conditions.

Availability

CY74FCT245CTQCT is available at Aetrix Electronics and suitable for industrial backplane isolation, legacy system bus extension, and microcontroller peripheral interface applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for CY74FCT245CTQCT 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.

The CY74FCT245CTQCT belongs to TI's FCT logic family, engineered specifically for robust, low-noise, bidirectional bus interfacing in commercial and industrial systems operating at 5 V with TTL-compatible signaling.

FAQ

What is the maximum propagation delay specification for CY74FCT245CTQCT?

The maximum propagation delay (tPLH/tPHL) for CY74FCT245CTQCT is 4.1 ns under recommended operating conditions (VCC = 4.75 V to 5.25 V, TA = –40°C to +85°C). This value is measured from input transition (A or B) to corresponding output transition (B or A) with CL = 50 pF and applies to both directions of data flow. The CY74FCT245CTQCT achieves this performance while maintaining full 5-V TTL compatibility and edge-rate control.

Does CY74FCT245CTQCT support partial-power-down operation?

Yes, CY74FCT245CTQCT supports partial-power-down operation via its Ioff circuitry. When VCC = 0 V, the Ioff feature disables all outputs, limiting leakage current to ±1 µA even if valid logic signals are present on A or B ports. This prevents damaging current backflow and ensures safe hot-swap capability - a key differentiator versus standard TTL or ACT transceivers that lack Ioff.

What package type and dimensions does CY74FCT245CTQCT use?

CY74FCT245CTQCT uses the QSOP-20 (DBQ) package: 20-pin, 0.64 mm lead pitch, 7.2 mm × 5.3 mm body size, and 1.2 mm maximum height. It features NiPdAu lead finish, complies with RoHS, and carries MSL Level-2-260°C-1 year rating. The pin 1 quadrant is Q1, and tape-and-reel packaging uses 2500 units per reel on 16.4-mm-wide carrier tape.

How does the T/R and OE control logic work on CY74FCT245CTQCT?

On CY74FCT245CTQCT, the T/R input controls data direction: T/R = high enables A→B transfer; T/R = low enables B→A transfer. The OE input is active-low - when OE = high, both A and B ports enter high-impedance state regardless of T/R state. When OE = low, direction is determined solely by T/R. This dual-control scheme allows independent bus arbitration and directional flexibility in complex multi-master systems.

Is CY74FCT245CTQCT compatible with standard TTL logic levels?

Yes, CY74FCT245CTQCT is fully compatible with standard TTL input and output logic levels. Its VIH (min 2.0 V) and VIL (max 0.8 V) thresholds match TTL specifications, and VOH (min 2.4 V at –32 mA) and VOL (max 0.55 V at 64 mA) meet or exceed TTL output drive requirements. This ensures seamless interoperability with legacy 5-V TTL devices without level-shifting circuitry.