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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

Texas Instruments CY74FCT543TQCT

Name: CY74FCT543TQCT
Brand: Texas Instruments
SKU: CY74FCT543TQCT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CY74FCT543TQCT

Manufacturer:: Texas Instruments

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 24-SSOP (0.154", 3.90mm Width)

Datasheet:: CY74FCT543TQCT.pdf

Description:: IC TXRX NON-INVERT 5.25V 24SSOP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

CY74FCT543TQCT from Texas Instruments is an octal latched registered transceiver with 3-state outputs, designed for bidirectional data flow control in TTL-compatible bus systems. It features independent A-to-B and B-to-A latch-enable (LEAB/LEBA) and output-enable (OEAB/OEBA) controls, 64-mA sink / 32-mA source drive strength, and operates at 4.75–5.25 V over –40°C to +85°C - used in industrial backplane interfaces and legacy system upgrades.

For engineers reviewing the CY74FCT543TQCT datasheet, CY74FCT543TQCT pinout, CY74FCT543TQCT application, or CY74FCT543TQCT equivalent, key selection criteria include bidirectional latch timing (t_su = 2 ns, t_PLH = 2.5–8.5 ns), I_off-enabled partial-power-down support, matched rise/fall times, edge-rate-controlled noise immunity, and QSOP-24 package compatibility with space-constrained PCB layouts.

Technical Context

This device implements dual 8-bit transparent latches with separate enable paths for each direction: CEAB/LEAB/OEAB govern A→B flow, while CEBA/LEBA/OEBA manage B→A flow. Each latch set supports independent storage mode entry via low-to-high LE transition and 3-state output control via active-low OE.

It integrates I_off circuitry that disables outputs when V_CC = 0 V, preventing backflow current during partial power-down. Edge-rate control minimizes ground bounce and crosstalk, and input thresholds (V_IL = 0.8 V, V_VIH = 2 V) ensure full TTL logic level compatibility.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	4.75–5.25 V - ensures stable operation across industrial voltage tolerances without external regulation
Output Drive	64 mA sink / 32 mA source - drives heavy capacitive loads and multiple TTL inputs directly
Propagation Delay	2.5–8.5 ns (t_PLH/t_PHL) - supports 100+ MHz bus clocking with margin for setup/hold timing
I_off Current	±1 µA at V_CC = 0 V - enables safe hot-insertion and mixed-voltage domain isolation
Input Thresholds	V_IL ≤ 0.8 V, V_IH ≥ 2.0 V - guarantees interoperability with standard TTL and LVTTL sources
ESD Rating	2000-V HBM, 200-V MM, 1000-V CDM - meets industrial-grade robustness requirements
Operating Temp	–40°C to +85°C - qualified for extended-temperature industrial and telecom environments

Pinout & Package

Package: SSOP-24 (DBQ), 5.3 mm × 7.2 mm body, 0.65 mm pitch, RoHS-compliant NiPdAu lead finish, MSL Level-2-260°C-1 year.

Pin/Terminal	Circuit Role	Design Meaning
1 (LEBA)	B-to-A latch-enable input	Active-low control: low enables transparency; rising edge captures B inputs into B→A latches
2 (OEBA)	B-to-A output-enable input	Active-low: enables/disables B→A 3-state outputs independently of latch state
3–10 (A0–A7)	A-side bidirectional terminals	Function as inputs (A→B) or high-impedance outputs (B→A) depending on CE/OE states
11 (CEAB)	A-to-B enable input	Active-low master gate: must be low to allow A→B data capture or B→A readback
12 (GND)	Ground reference	Primary return path for all I/O and internal logic; requires low-inductance connection
13 (V_CC)	Power supply	5-V nominal supply; decoupling capacitor required within 1 cm for noise suppression
14 (CEBA)	B-to-A enable input	Active-low master gate for B→A path; orthogonal to CEAB for full bidirectional arbitration
15–22 (B0–B7)	B-side bidirectional terminals	Function as inputs (B→A) or high-impedance outputs (A→B); electrically identical to A pins
23 (LEAB)	A-to-B latch-enable input	Active-low: rising edge stores A inputs into A→B latches; enables synchronous capture
24 (OEAB)	A-to-B output-enable input	Active-low: controls 3-state drivers for A→B outputs without affecting latch contents

Key Features

Feature	Design Value
Dual independent 8-bit latch paths	Enables concurrent A↔B data staging without bus contention or arbitration logic
I_off partial-power-down protection	Prevents reverse current flow when V_CC is off, supporting live insertion and hot-swap systems
Edge-rate controlled outputs	Reduces simultaneous switching noise (SSN) by limiting dV/dt - critical for dense backplanes
Matched rise/fall times	Minimizes duty-cycle distortion on clocked data buses, preserving signal integrity
TTL-compatible input/output levels	Interoperates with legacy 5-V TTL, LVTTL, and CMOS logic without level-shifting components

Applications

Industrial Backplane Interface	Legacy System Bus Extension
Use Scenario: Bidirectional data transfer between CPU module and I/O expansion cards in modular PLC chassis. IC Role / Device Role / Timing Role: Acts as a registered transceiver buffering and latching address/data/control signals across isolated board-to-board connectors. Use Value: Eliminates need for discrete latch + buffer combinations; 2.5-ns min t_PLH ensures timing closure at 20-MHz bus rates.	Use Scenario: Extending a vintage 8-bit microprocessor data bus to add memory-mapped peripherals in retro-computing restoration. IC Role / Device Role / Timing Role: Provides direction-controlled, latched data path between Z80 CPU and SRAM/IO chips with precise LE timing. Use Value: Matches TTL logic thresholds and drive strength exactly; eliminates level-shifter design overhead.
Telecom Line Card Data Routing	Test Equipment Signal Conditioning
Use Scenario: Isolating and synchronizing control/status signals between FPGA-based control plane and analog front-end ASIC on line cards. IC Role / Device Role / Timing Role: Serves as a direction-gated, latch-stabilized interface with I_off enabling safe FPGA reconfiguration mid-operation. Use Value: I_off prevents backfeed during FPGA power cycling; 64-mA sink handles LED driver loads directly.	Use Scenario: Buffering and latching DUT signals in automated test equipment where signal integrity and deterministic timing are critical. IC Role / Device Role / Timing Role: Captures parallel stimulus/response data with sub-3-ns setup time and holds values for measurement subsystem sampling. Use Value: Matched rise/fall times prevent pulse skew; edge-rate control suppresses EMI in sensitive RF test chambers.

Industrial Backplane Interface

Legacy System Bus Extension

Use Scenario: Bidirectional data transfer between CPU module and I/O expansion cards in modular PLC chassis.

IC Role / Device Role / Timing Role: Acts as a registered transceiver buffering and latching address/data/control signals across isolated board-to-board connectors.

Use Value: Eliminates need for discrete latch + buffer combinations; 2.5-ns min t_PLH ensures timing closure at 20-MHz bus rates.

Use Scenario: Extending a vintage 8-bit microprocessor data bus to add memory-mapped peripherals in retro-computing restoration.

IC Role / Device Role / Timing Role: Provides direction-controlled, latched data path between Z80 CPU and SRAM/IO chips with precise LE timing.

Use Value: Matches TTL logic thresholds and drive strength exactly; eliminates level-shifter design overhead.

Telecom Line Card Data Routing

Test Equipment Signal Conditioning

Use Scenario: Isolating and synchronizing control/status signals between FPGA-based control plane and analog front-end ASIC on line cards.

IC Role / Device Role / Timing Role: Serves as a direction-gated, latch-stabilized interface with I_off enabling safe FPGA reconfiguration mid-operation.

Use Value: I_off prevents backfeed during FPGA power cycling; 64-mA sink handles LED driver loads directly.

Use Scenario: Buffering and latching DUT signals in automated test equipment where signal integrity and deterministic timing are critical.

IC Role / Device Role / Timing Role: Captures parallel stimulus/response data with sub-3-ns setup time and holds values for measurement subsystem sampling.

Use Value: Matched rise/fall times prevent pulse skew; edge-rate control suppresses EMI in sensitive RF test chambers.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74FCT543ATQCT	Same pinout and function but rated for 5.3-ns max propagation delay (vs. 8.5 ns for CY74FCT543TQCT); lower drive (48 mA sink / 12 mA source)	Suitable for higher-speed designs where timing margin is tight but drive load is lighter	Select SN74FCT543ATQCT when operating frequency exceeds 25 MHz and load capacitance < 30 pF per line
74ACT543SCX	CMOS-based, 5-V only, 12-mA drive, no I_off, slower t_PLH (9 ns typ), different pinout (SOIC-24 only)	Lacks partial-power-down support and edge-rate control; not drop-in compatible	Choose 74ACT543SCX only if migrating from older ACT family and board layout allows SOIC-24 footprint change

Compared with SN74FCT543ATQCT and 74ACT543SCX, CY74FCT543TQCT delivers higher drive strength and I_off safety for industrial hot-swap use cases, at the cost of slightly relaxed timing - making it optimal for robust, moderate-speed bus isolation where reliability trumps peak speed.

Availability

CY74FCT543TQCT is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, and telecom line card data routing requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for CY74FCT543TQCT 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 FCT logic family - including CY74FCT543TQCT - was engineered for high-noise immunity, TTL compatibility, and robust operation in mission-critical industrial and telecom infrastructure.

FAQ

What is the maximum clock rate supported by CY74FCT543TQCT in a bidirectional bus application?

CY74FCT543TQCT does not operate on a clock signal - it is an edge-triggered latch device. Its usable data rate depends on propagation delay (2.5–8.5 ns) and setup/hold timing (t_su = 2 ns, t_th = 2 ns). For reliable operation with margin, it supports sustained bidirectional bus cycles up to ~25 MHz in typical PCB layouts with ≤50-pF load per line. The CY74FCT543TQCT datasheet specifies timing under defined test conditions, not guaranteed clock frequency.

Does CY74FCT543TQCT support hot-swap or partial-power-down operation?

Yes. CY74FCT543TQCT includes I_off circuitry that disables outputs when V_CC = 0 V, limiting reverse current to ±1 µA. This enables safe hot-insertion into powered backplanes and partial-power-down modes in multi-rail systems. The CY74FCT543TQCT maintains this behavior across its full temperature range and is explicitly characterized for I_off in the datasheet's electrical characteristics table.

Can CY74FCT543TQCT replace CY54FCT543T in existing designs?

CY74FCT543TQCT and CY54FCT543T share identical logic functionality and pinout but differ in temperature rating (–40°C to +85°C vs. –55°C to +125°C) and drive strength (64/32 mA vs. 48/12 mA). CY74FCT543TQCT is not a direct replacement in military or extended-temperature applications. However, for commercial-temperature designs with higher drive demands, CY74FCT543TQCT can be substituted if the PCB layout accommodates the QSOP-24 package and power delivery supports the increased I_OL.

What package type is used for CY74FCT543TQCT, and is it RoHS-compliant?

CY74FCT543TQCT uses the SSOP-24 (DBQ) package: 5.3 mm × 7.2 mm body, 0.65 mm lead pitch, with NiPdAu lead finish. It is RoHS-compliant (lead-free), rated MSL Level-2-260°C-1 year, and supplied in tape-and-reel format (2500 units per reel). The CY74FCT543TQCT marking "FCT543" appears on the top surface per TI's standard part identification scheme.

How does the edge-rate control in CY74FCT543TQCT improve system-level noise performance?

CY74FCT543TQCT incorporates internal edge-rate control circuitry that limits output dV/dt, reducing simultaneous switching noise (SSN) and ground bounce. This results in significantly lower radiated emissions and crosstalk compared to standard FCT devices - verified by TI's characterization showing >10 dB improvement in near-field EMI at 100–500 MHz. The CY74FCT543TQCT achieves this without external resistors or layout compromises, making it ideal for dense, noise-sensitive applications like telecom line cards.

CY74FCT543TQCT Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74FCT

Package/Case:: 24-SSOP (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Logic Type:: Transceiver, Non-Inverting

Number of Elements:: 1

Number of Bits per Element:: 8

Input Type:: -

Output Type:: 3-State

Current - Output High, Low:: 32mA, 64mA

Voltage - Supply:: 4.75V ~ 5.25V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 24-SSOP

CY74FCT543TQCT FAQ

1.How can I place an order for CY74FCT543TQCT through Aetrix?

Please submit a Request for Quotation (RFQ) for CY74FCT543TQCT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for CY74FCT543TQCT reliable?

The price and inventory of CY74FCT543TQCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY74FCT543TQCT is usually 5 days.

3.What payment methods are accepted for CY74FCT543TQCT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY74FCT543TQCT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CY74FCT543TQCT?

CY74FCT543TQCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CY74FCT543TQCT order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for CY74FCT543TQCT?

For technical support, including CY74FCT543TQCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY74FCT543TQCT requirements.

6.How does Aetrix verify that CY74FCT543TQCT is sourced from the original manufacturer or authorized distributors?

All CY74FCT543TQCT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that CY74FCT543TQCT meets industry standards.

7.What is the process for return or replacement of CY74FCT543TQCT?

All CY74FCT543TQCT units undergo pre-shipment inspection (PSI). If there is an issue with CY74FCT543TQCT, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The CY74FCT543TQCT part is unused and in its original packaging.

Return procedure for CY74FCT543TQCT:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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