Texas Instruments CY74FCT2543CTSOC

Overview

CY74FCT2543CTSOC from Texas Instruments is an 8-bit latched transceiver with 3-state outputs in SOIC-24 package, supporting bidirectional data flow between two 8-bit buses. It features independent A-to-B and B-to-A latch enable (LEAB/LEBA) and output enable (OEAB/OEBA) controls, 25-Ω on-chip series output resistors for reflection noise reduction, 5.5 ns max propagation delay (tPLH/tPHL), and Ioff support for partial-power-down mode operation.

For engineers reviewing the CY74FCT2543CTSOC datasheet, CY74FCT2543CTSOC pinout, CY74FCT2543CTSOC application, or CY74FCT2543CTSOC equivalent, key selection criteria include bidirectional latch timing control, TTL-compatible logic levels, 3.3 V typical VOH, 12 mA sink / 15 mA source drive strength, and SOIC-24 thermal performance (θJA = 46°C/W).

Technical Context

The CY74FCT2543CTSOC integrates two independent sets of eight D-type latches with separate CEAB/CEBA enable inputs and LEAB/LEBA latch-enable controls, enabling asynchronous bidirectional data capture. Its edge-rate control circuitry and matched rise/fall times reduce system-level EMI, while internal 25-Ω series termination resistors suppress transmission-line reflections without external components.

Ioff functionality disables outputs when VCC = 0 V, limiting reverse current to ±1 µA and enabling safe hot-insertion or partial-power-down in mixed-voltage systems. The device operates across –40°C to +85°C with 4.75–5.25 V supply, fully compatible with TTL input thresholds (VIL = 0.8 V, VIH = 2.0 V) and output drive levels.

Key Specifications

Pinout & Package

SOIC-24 package (DW), 7.5 mm × 15.4 mm body, 1.27 mm pitch, RoHS-compliant NIPDAU finish, MSL Level-1 (unlimited reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY74FCT2543CTSOC, CY74FCT2543ATSOC trades 1 ns of speed for lower cost in identical SOIC-24 packaging, while SN74FCT2543CTSO offers identical electrical and timing performance with TI-native documentation and lifecycle management-making it ideal for production continuity planning.

Availability

CY74FCT2543CTSOC is available at Aetrix Electronics and suitable for industrial control backplanes, legacy bus bridging, memory expansion subsystems, and automated test equipment requiring stable component supply and guaranteed long-term sourcing.

Supply support for CY74FCT2543CTSOC 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 with emphasis on reliability, longevity, and industrial-grade qualification.

The CY74FCT2543CTSOC belongs to TI's FCT (Fast CMOS TTL-compatible) logic family, designed specifically for noise-immune, high-drive bidirectional bus interfacing in industrial, telecom, and instrumentation systems operating at 5 V.

FAQ

What is the maximum propagation delay specification for CY74FCT2543CTSOC?

The CY74FCT2543CTSOC has a maximum propagation delay (tPLH/tPHL) of 5.5 ns under recommended operating conditions (VCC = 4.75–5.25 V, TA = –40°C to +85°C). This value applies to both A→B and B→A signal paths and is measured with CL = 50 pF load. The 5.5 ns rating makes CY74FCT2543CTSOC suitable for high-speed 8-bit bus applications requiring sub-10 ns timing margins.

Does CY74FCT2543CTSOC support partial-power-down operation?

Yes, CY74FCT2543CTSOC supports partial-power-down via its Ioff circuitry. When VCC = 0 V, the outputs are disabled and leakage current is limited to ±1 µA even if up to 4.5 V is applied at any I/O pin. This feature protects downstream circuitry during power sequencing, hot-swap events, or mixed-supply system operation-enabling safe use in modular backplane architectures.

What package type and dimensions does CY74FCT2543CTSOC use?

CY74FCT2543CTSOC uses the SOIC-24 (DW) package: 7.5 mm × 15.4 mm body size, 1.27 mm lead pitch, 2.35 mm nominal height. It is supplied in tube packaging (25 units per tube), RoHS-compliant with NIPDAU lead finish, and rated MSL Level-1 (unlimited floor life at ≤30°C/60% RH). Thermal resistance is θJA = 46°C/W.

How does the on-chip 25-Ω series termination in CY74FCT2543CTSOC improve signal integrity?

The CY74FCT2543CTSOC integrates 25-Ω series resistors at each output driver to match typical PCB trace impedance (50–75 Ω in parallel configuration), thereby reducing transmission-line reflections that cause ringing, overshoot, and timing uncertainty. This eliminates the need for 8 discrete 25-Ω resistors on the board, simplifying layout, lowering BOM cost, and improving consistency across all 16 I/O lines without manual tuning.

Can CY74FCT2543CTSOC replace CY74FCT543T in existing designs?

Yes, CY74FCT2543CTSOC is functionally and pinout-compatible with CY74FCT543T and can serve as a drop-in replacement to reduce system noise. Both devices share identical pin assignments, logic behavior, and DC specifications. However, CY74FCT2543CTSOC adds 25-Ω output series resistors and improved edge-rate control-providing superior noise immunity without requiring PCB changes or firmware updates.