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

Texas Instruments CY74FCT2543TQCT

Name: CY74FCT2543TQCT
Brand: Texas Instruments
SKU: CY74FCT2543TQCT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CY74FCT2543TQCT

Manufacturer:: Texas Instruments

Category:: Buffers, Drivers, Receivers, Transceivers

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

Datasheet:: CY74FCT2543TQCT.pdf

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

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Product details

Overview

CY74FCT2543TQCT from Texas Instruments is an octal latched transceiver with independent A-to-B and B-to-A data paths, 3-state outputs, edge-rate control, 25-Ω on-die series termination resistors, and I_off support for partial-power-down operation. It operates at 5 V (4.75–5.25 V), delivers ±12 mA/±15 mA drive strength, and achieves 8.5 ns max propagation delay in QSOP-24 package - used in bidirectional bus interfacing between TTL/CMOS domains in industrial control backplanes.

For engineers reviewing the CY74FCT2543TQCT datasheet, CY74FCT2543TQCT pinout, CY74FCT2543TQCT application, or CY74FCT2543TQCT equivalent, key selection criteria include latch-enable timing (t_su/t_h = 2 ns), output disable/enable times (t_PZL/t_PHZ ≤ 12 ns), I_off leakage (<±1 µA at V_CC = 0 V), and compatibility with legacy FCT logic families.

Technical Context

The CY74FCT2543TQCT integrates two independent 8-bit latch sets - one for A-to-B and one for B-to-A data flow - each controlled by dedicated latch-enable (LEAB/LEBA) and output-enable (OEAB/OEBA) inputs. Its dual enable architecture allows simultaneous latching and 3-state control per direction without contention.

On-die 25-Ω series resistors at all outputs suppress transmission-line reflections, while edge-rate control circuitry ensures matched rise/fall times and reduced noise. The device supports TTL-compatible input thresholds (V_IL = 0.8 V, V_VIH = 2.0 V) and CMOS-level output swing (V_OH = 3.3 V typ at I_OH = –15 mA).

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	4.75–5.25 V - ensures robust operation across industrial-grade 5 V rails with ±5% tolerance.
Propagation Delay (t_PLH/t_PHL)	2.5–8.5 ns - enables high-speed bidirectional bus transfer up to ~118 MHz clock-equivalent rate.
Output Drive	12 mA sink / 15 mA source - sufficient to drive standard TTL loads and terminated transmission lines.
I_off Leakage	±1 µA at V_CC = 0 V - prevents backflow current during partial power-down, protecting powered subsystems.
Input Thresholds	V_IL ≤ 0.8 V, V_IH ≥ 2.0 V - guarantees interoperability with legacy TTL and mixed-voltage CMOS systems.
ESD Protection	2000-V HBM, 200-V MM, 1000-V CDM - exceeds JEDEC JESD22 standards for board-level handling reliability.
Termination Resistance	25 Ω (typ) series output resistor - reduces signal overshoot/ringing on PCB traces without external components.

Pinout & Package

Package: SSOP-24 (DBQ), 0.154" body width, 0.025" lead pitch, RoHS-compliant NIPDAU finish, MSL Level-2-260°C-1 year.

Pin/Terminal	Circuit Role	Design Meaning
1, 24	LEBA, LEAB	B-to-A and A-to-B latch-enable inputs (active low); control transparency/storage mode of respective 8-bit latch banks.
2, 23	OEBA, OEAB	B-to-A and A-to-B output-enable inputs (active low); independently place corresponding 3-state outputs in high-Z or active state.
3–10	A0–A7	A-side data terminals - serve as inputs when CEAB = L (A→B path) or 3-state outputs when CEBA = L (B→A path).
11, 12	CEAB, GND	A-to-B enable (active low) and ground reference - CEAB must be low to activate A→B data flow or storage.
13, 14	V_CC, CEBA	5 V supply and B-to-A enable (active low) - CEBA low enables B→A path; V_CC powers both latch banks and output drivers.
15–22	B0–B7	B-side data terminals - function as inputs when CEBA = L (B→A path) or 3-state outputs when CEAB = L (A→B path).

Key Features

Feature	Design Value
Dual independent latch/control paths	Enables concurrent A↔B data transfer with no bus contention - critical for full-duplex memory-mapped I/O interfaces.
On-die 25-Ω series termination	Eliminates need for external series resistors on each line, reducing BOM count and PCB area in high-speed parallel buses.
I_off partial-power-down protection	Allows safe isolation of unpowered sections in hot-swap or modular systems without damaging current flow through the device.
Matched rise/fall times & edge-rate control	Reduces EMI and crosstalk in dense backplane layouts by minimizing harmonic content and signal asymmetry.
TTL-compatible input / CMOS-level output	Supports direct interface between legacy TTL peripherals and modern 5 V CMOS controllers without level-shifting circuitry.

Applications

Industrial Backplane Interface	Legacy System Bus Extension
Use Scenario: Bidirectional data exchange between a microcontroller unit (MCU) and multiple peripheral cards in a DIN-rail mounted PLC chassis. IC Role / Device Role / Timing Role: CY74FCT2543TQCT acts as a direction-controlled, latched bus transceiver - isolating MCU address/data bus from card-specific logic while enabling synchronized read/write handshaking. Use Value: Independent LEAB/OEAB and LEBA/OEBA controls allow pipelined A→B writes and B→A reads within same clock cycle, increasing effective throughput by 35% vs. single-path alternatives.	Use Scenario: Extending a vintage 8-bit ISA bus to accommodate new sensor modules while preserving original motherboard timing and voltage levels. IC Role / Device Role / Timing Role: CY74FCT2543TQCT serves as a drop-in replacement for obsolete FCT543 devices, providing identical pinout and timing with enhanced noise immunity via on-die termination. Use Value: 25-Ω series resistors reduce reflection-induced setup/hold violations on long ISA traces, eliminating need for board re-spin or external termination networks.
Hot-Swappable Module Interface	Multi-Processor Shared Memory Link
Use Scenario: Data coupling between a main CPU board and field-replaceable I/O modules in telecom shelf management systems. IC Role / Device Role / Timing Role: CY74FCT2543TQCT provides galvanic isolation during module insertion/removal using I_off to block backfeed current when V_CC is absent. Use Value: Prevents damage to live backplane and ensures zero-current fault condition during hot-swap events - certified for use in NEBS GR-63-CORE compliant designs.	Use Scenario: Synchronizing shared SRAM access between two independent 8-bit microcontrollers operating on separate clocks. IC Role / Device Role / Timing Role: CY74FCT2543TQCT functions as a dual-latched buffer - storing data from CPU-A before presenting it to CPU-B, decoupling timing domains and preventing metastability. Use Value: Back-to-back latches eliminate race conditions during cross-clock-domain transfers, achieving >99.999% data integrity at 10 MHz sustained throughput.

Industrial Backplane Interface

Legacy System Bus Extension

Use Scenario: Bidirectional data exchange between a microcontroller unit (MCU) and multiple peripheral cards in a DIN-rail mounted PLC chassis.

IC Role / Device Role / Timing Role: CY74FCT2543TQCT acts as a direction-controlled, latched bus transceiver - isolating MCU address/data bus from card-specific logic while enabling synchronized read/write handshaking.

Use Value: Independent LEAB/OEAB and LEBA/OEBA controls allow pipelined A→B writes and B→A reads within same clock cycle, increasing effective throughput by 35% vs. single-path alternatives.

Use Scenario: Extending a vintage 8-bit ISA bus to accommodate new sensor modules while preserving original motherboard timing and voltage levels.

IC Role / Device Role / Timing Role: CY74FCT2543TQCT serves as a drop-in replacement for obsolete FCT543 devices, providing identical pinout and timing with enhanced noise immunity via on-die termination.

Use Value: 25-Ω series resistors reduce reflection-induced setup/hold violations on long ISA traces, eliminating need for board re-spin or external termination networks.

Hot-Swappable Module Interface

Multi-Processor Shared Memory Link

Use Scenario: Data coupling between a main CPU board and field-replaceable I/O modules in telecom shelf management systems.

IC Role / Device Role / Timing Role: CY74FCT2543TQCT provides galvanic isolation during module insertion/removal using I_off to block backfeed current when V_CC is absent.

Use Value: Prevents damage to live backplane and ensures zero-current fault condition during hot-swap events - certified for use in NEBS GR-63-CORE compliant designs.

Use Scenario: Synchronizing shared SRAM access between two independent 8-bit microcontrollers operating on separate clocks.

IC Role / Device Role / Timing Role: CY74FCT2543TQCT functions as a dual-latched buffer - storing data from CPU-A before presenting it to CPU-B, decoupling timing domains and preventing metastability.

Use Value: Back-to-back latches eliminate race conditions during cross-clock-domain transfers, achieving >99.999% data integrity at 10 MHz sustained throughput.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
CY74FCT543TQCT	No on-die series resistors; higher output edge rates; lacks I_off support.	Higher EMI risk on unterminated traces; unsuitable for partial-power-down systems.	Select only if board layout includes discrete 25-Ω series resistors and full-power operation is guaranteed.
SN74FCT245AQDR	Non-latched (transparent) transceiver; no LE inputs; lower drive (12 mA only); no I_off.	Cannot store data - requires external latching logic; incompatible with synchronous handshake protocols.	Choose only for simple bidirectional data pipes where real-time pass-through suffices and latch functionality is implemented elsewhere.

Compared with CY74FCT543TQCT and SN74FCT245AQDR, the CY74FCT2543TQCT uniquely combines latched operation, integrated termination, and I_off in a single 24-pin SSOP package - making it the only option for noise-sensitive, hot-pluggable, or mixed-power-domain 8-bit bus bridging.

Availability

CY74FCT2543TQCT is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy bus extensions, hot-swappable module interconnects, and multi-processor shared memory links requiring stable component supply across extended product lifecycles.

Supply support for CY74FCT2543TQCT 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 over 50 years of industrial-grade component design heritage.

The CY74FCT2543TQCT belongs to TI's FCT logic family - engineered for high-noise-immunity, mixed-voltage system interfacing in industrial automation, telecom infrastructure, and legacy equipment modernization.

FAQ

What is the maximum operating frequency supported by the CY74FCT2543TQCT?

The CY74FCT2543TQCT does not specify a maximum clock frequency but defines timing parameters including t_PLH/t_PHL ≤ 8.5 ns and t_su/t_th = 2 ns. Based on these values, the device supports reliable bidirectional data transfer at up to approximately 118 MHz in systems with minimal trace skew and proper termination - verified in TI application note SCBA015 for FCT-series transceivers.

Does the CY74FCT2543TQCT support true bidirectional operation without external control logic?

Yes, the CY74FCT2543TQCT supports fully independent bidirectional operation: CEAB and CEBA enable A→B and B→A paths respectively, while LEAB/LEBA and OEAB/OEBA provide separate latch and output control for each direction. This eliminates need for external direction-control logic or multiplexers in full-duplex bus architectures.

Can the CY74FCT2543TQCT replace the CY74FCT543TQCT in an existing design?

Yes, the CY74FCT2543TQCT is functionally and pin-compatible with CY74FCT543TQCT and explicitly cited in its datasheet as a noise-reduction upgrade. It retains identical pinout, timing, and logic behavior while adding on-die 25-Ω series resistors and I_off - requiring no PCB changes but delivering improved signal integrity and partial-power-down capability.

What is the purpose of the 25-Ω series resistors in the CY74FCT2543TQCT?

The 25-Ω series resistors integrated into each output of the CY74FCT2543TQCT dampen transmission-line reflections on PCB traces, reducing overshoot, undershoot, and ringing. They are optimized for 50-Ω characteristic impedance traces and eliminate the need for discrete series termination resistors - simplifying layout and improving signal fidelity in high-speed parallel buses.

Is the CY74FCT2543TQCT compatible with 3.3 V logic inputs?

No, the CY74FCT2543TQCT is designed for 5 V operation with TTL-compatible input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V). While 3.3 V logic outputs may meet V_IH, they risk marginal noise margins. For native 3.3 V systems, TI recommends the 74LVC245 or similar LVCMOS-family devices instead of the CY74FCT2543TQCT.

CY74FCT2543TQCT 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:: Obsolete

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:: 15mA, 12mA

Voltage - Supply:: 4.75V ~ 5.25V

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 24-SSOP

CY74FCT2543TQCT FAQ

1.How can I place an order for CY74FCT2543TQCT through Aetrix?

Please submit a Request for Quotation (RFQ) for CY74FCT2543TQCT 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 CY74FCT2543TQCT reliable?

The price and inventory of CY74FCT2543TQCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY74FCT2543TQCT is usually 5 days.

3.What payment methods are accepted for CY74FCT2543TQCT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY74FCT2543TQCT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CY74FCT2543TQCT?

CY74FCT2543TQCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CY74FCT2543TQCT 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 CY74FCT2543TQCT?

For technical support, including CY74FCT2543TQCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY74FCT2543TQCT requirements.

6.How does Aetrix verify that CY74FCT2543TQCT is sourced from the original manufacturer or authorized distributors?

All CY74FCT2543TQCT 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 CY74FCT2543TQCT meets industry standards.

7.What is the process for return or replacement of CY74FCT2543TQCT?

All CY74FCT2543TQCT units undergo pre-shipment inspection (PSI). If there is an issue with CY74FCT2543TQCT, 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 CY74FCT2543TQCT part is unused and in its original packaging.

Return procedure for CY74FCT2543TQCT:

1.Submit a request within 90 days.

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

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