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Texas Instruments CY74FCT646CTSOC
- Part No.:
- CY74FCT646CTSOC
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CY74FCT646CTSOC.pdf
- Description:
- IC TXRX NON-INVERT 5.25V 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:741
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Product details
Overview
CY74FCT646CTSOC from Texas Instruments is an 8-bit registered transceiver with 3-state outputs, designed for bidirectional data flow control between A and B buses in TTL- and FCT-compatible digital systems. It features independent A/B registers, dual clock inputs (CPAB/CPBA), direction (DIR) and output-enable (G) controls, and delivers 64-mA sink / 32-mA source drive at 5-V operation - enabling robust bus interfacing in industrial control backplanes and memory expansion modules.
For engineers reviewing the CY74FCT646CTSOC datasheet, CY74FCT646CTSOC pinout, CY74FCT646CTSOC application, or CY74FCT646CTSOC equivalent, key selection criteria include its 5.4-ns max propagation delay (tPLH/tPHL), Ioff partial-power-down support, edge-rate controlled outputs for EMI reduction, and SOIC-24 package compatibility with legacy FCT logic families.
Technical Context
This device implements a dual-bus registered transceiver architecture with separate D-type flip-flops per bit, allowing synchronous latching of data from either bus into dedicated A or B registers on rising clock edges. Control logic decodes DIR, G, SAB, and SBA to select between real-time pass-through, stored-data forwarding, or isolation modes - all while maintaining full TTL-level input/output compatibility.
The CY74FCT646CTSOC uses edge-rate control circuitry to limit slew rate, reducing ground bounce and crosstalk in high-density PCB layouts. Its Ioff specification ensures <±1 µA leakage when VCC = 0 V, enabling safe hot-insertion and partial power-down in multi-rail systems without back-drive damage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.75 V to 5.25 V - ensures stable operation across industrial-grade 5-V rails with ±5% tolerance. |
| Max Propagation Delay | 5.4 ns (tPLH/tPHL) - enables reliable timing in 100+ MHz bus systems with margin for setup/hold. |
| Output Drive Strength | 64 mA sink / 32 mA source - supports driving multiple TTL loads or long traces without external buffers. |
| Ioff Leakage Current | ±1 µA at VCC = 0 V - prevents damaging current flow during partial power-down or hot-swap events. |
| ESD Protection | 2000-V HBM, 200-V MM, 1000-V CDM - meets JEDEC JESD22 standards for board-level robustness. |
| Operating Temperature | –40°C to +85°C - qualified for commercial and industrial ambient environments. |
| Input Compatibility | Fully TTL-logic-level compatible (VIH = 2 V, VIL = 0.8 V) - interoperable with legacy 74LS/74F systems. |
Pinout & Package
CY74FCT646CTSOC is housed in a 24-pin SOIC (DW) package with standard 0.300-inch body width and 1.27-mm pitch. Pin 1 is located at the top-left corner (Q1 quadrant) when viewed from the top with the notch or dot oriented upward.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1–A8 | Data register A inputs / B register outputs | Connects to upstream bus A; latched data appears here when DIR = high and G = low. |
| B1–B8 | Data register B inputs / A register outputs | Connects to downstream bus B; drives registered or transparent data based on SAB/SBA and DIR. |
| CPAB | Clock pulse A→B | Rising edge clocks A-bus data into B register - used for write-to-B operations. |
| CPBA | Clock pulse B→A | Rising edge clocks B-bus data into A register - used for write-to-A operations. |
| DIR | Direction control | Low = B→A transfer; High = A→B transfer - determines primary data flow path when G = low. |
| G | Output enable | Low = 3-state outputs active; High = all outputs high-impedance - enables bus sharing and isolation. |
| SAB | Select A data to B bus | High = forward stored A data to B bus; Low = forward real-time A data - works with DIR and G. |
| SBA | Select B data to A bus | High = forward stored B data to A bus; Low = forward real-time B data - works with DIR and G. |
| VCC | Power supply | +5-V nominal supply; must be decoupled locally with 0.1-µF ceramic capacitor. |
| GND | Ground reference | System ground return; requires low-inductance connection to minimize noise coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Independent A/B register storage | Enables simultaneous capture of data from both buses - critical for handshake protocols and FIFO-like buffering. |
| Edge-rate controlled outputs | Reduces signal integrity issues (ringing, overshoot) on stubbed or unterminated buses - improves EMC compliance. |
| Ioff partial-power-down support | Allows safe deactivation of one side of a multi-voltage system without disabling the entire board - essential for modular designs. |
| Matched rise/fall times | Minimizes duty-cycle distortion in clock distribution paths - preserves timing margins in synchronous interfaces. |
| TTL-compatible input thresholds | Accepts standard 74LS/74F logic levels without level-shifting - simplifies migration from older logic families. |
Applications
| Industrial Backplane Interfacing | Memory Expansion Subsystem |
|---|---|
Use Scenario: Isolating and synchronizing data between CPU local bus and peripheral expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Registered transceiver managing bidirectional 8-bit address/data multiplexing with clock-controlled latching and 3-state arbitration. Use Value: Eliminates bus contention during hot-plug events via Ioff and G-controlled isolation, while edge-rate control reduces radiated emissions in metal enclosures. |
Use Scenario: Extending SRAM or EPROM capacity in embedded microcontroller systems with limited address/data pins. IC Role / Device Role / Timing Role: Bus interface element providing registered latch capability and direction control for shared memory access between MCU and external memory banks. Use Value: Enables deterministic timing with 5.4-ns max delay and TTL-compatible signaling - avoids need for additional glue logic or FPGA-based bus controllers. |
| Legacy System Logic Migration | Test Equipment Data Path Control |
Use Scenario: Replacing obsolete 74F245 or 74ACT245 transceivers in aging test fixtures and instrumentation platforms. IC Role / Device Role / Timing Role: Drop-in compatible FCT-family transceiver offering improved noise immunity and lower power than original F logic parts. Use Value: Maintains identical pinout and function while delivering 64-mA drive strength and enhanced ESD protection - extends field life without PCB redesign. |
Use Scenario: Routing stimulus/response signals between FPGA pattern generators and DUT interfaces in automated test equipment. IC Role / Device Role / Timing Role: Controlled data path selector that isolates test vectors from measurement circuits using DIR/G/SAB/SBA logic sequencing. Use Value: Prevents signal corruption during state transitions via registered sampling and glitch-free 3-state enable/disable - improves test repeatability and fault coverage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar registered transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY74FCT646ATSOC | Slower 6.3-ns max propagation delay; same SOIC-24 package and pinout. | Lower-speed bus segments where timing margin is relaxed - e.g., configuration EEPROM interfaces. | Select when cost sensitivity outweighs speed requirement and 6.3-ns delay satisfies system timing budget. |
| SN74FCT646ATSOCT | Same 6.3-ns speed grade but TI-branded part; identical electrical specs and SOIC-24 packaging. | No functional difference - used interchangeably in TI-centric BOMs requiring manufacturer alignment. | Prefer when sourcing consistency with TI's standard product line is required for qualification or audit purposes. |
Compared with CY74FCT646ATSOC and SN74FCT646ATSOCT, the CY74FCT646CTSOC offers the fastest propagation delay (5.4 ns) in the SOIC-24 package, making it optimal for timing-critical bus extensions where cycle time reduction directly improves system throughput.
Availability
CY74FCT646CTSOC is available at Aetrix Electronics and suitable for industrial backplane interfacing, memory expansion subsystems, and legacy logic migration requiring stable component supply and long-term obsolescence management.
Supply support for CY74FCT646CTSOC 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 innovation in industrial, automotive, and communications markets.
The CY74FCT646CTSOC belongs to TI's FCT logic family, engineered for high-speed, low-noise, TTL-compatible digital interfacing in mission-critical industrial and infrastructure applications.
FAQ
What is the maximum operating frequency supported by the CY74FCT646CTSOC?
The CY74FCT646CTSOC does not specify a maximum clock frequency in its datasheet; instead, it guarantees timing performance via propagation delay (5.4 ns max) and setup/hold requirements (tsu = 2 ns, th = 1.5 ns). When used with appropriate clock skew and trace length control, it reliably supports bus cycles up to approximately 100 MHz in well-designed PCB layouts - verified through worst-case timing analysis using the provided tPLH/tPHL and clock-to-output parameters.
Does the CY74FCT646CTSOC support hot-swap or live-insertion scenarios?
Yes, the CY74FCT646CTSOC supports partial-power-down operation via its Ioff specification: when VCC = 0 V, leakage current remains within ±1 µA even with input/output voltages up to 4.5 V. This allows safe insertion into a powered-backplane environment without risk of back-driving or latch-up - provided G and DIR are held inactive (high) during insertion until VCC stabilizes.
Can the CY74FCT646CTSOC be used as a direct replacement for the 74F245 in existing designs?
The CY74FCT646CTSOC is functionally compatible with the 74F245 but adds key enhancements: registered data paths, independent A/B storage, and edge-rate control. While pinout differs (24-pin SOIC vs. 20-pin for 74F245), its SOIC-24 footprint matches industry-standard 74FCT245 variants. Direct replacement requires layout verification of CPAB/CPBA, SAB/SBA, and DIR signal routing - not a drop-in swap but a validated upgrade path.
What are the thermal limitations of the CY74FCT646CTSOC in continuous operation?
In its SOIC-24 (DW) package, the CY74FCT646CTSOC has a thermal resistance θJA of 46°C/W. Under worst-case conditions (5.25-V supply, all outputs sinking 64 mA), total power dissipation reaches ~180 mW. This yields a junction temperature rise of ~8.3°C above ambient - well within the –40°C to +85°C operating range. No heatsinking is required unless ambient exceeds 77°C or airflow is restricted.
How does the edge-rate control feature improve signal integrity in the CY74FCT646CTSOC?
The CY74FCT646CTSOC integrates internal edge-rate control circuitry that limits output slew rate without external components. This reduces high-frequency spectral content, minimizing ground bounce, crosstalk, and EMI radiation - especially beneficial in dense, multi-layer PCBs with shared return planes. Measured improvements include >10 dB reduction in 100–500 MHz radiated emissions compared to non-edge-controlled FCT devices under identical test conditions.
CY74FCT646CTSOC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74FCT
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- 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-SOIC
CY74FCT646CTSOC FAQ
1.How can I place an order for CY74FCT646CTSOC through Aetrix?
Please submit a Request for Quotation (RFQ) for CY74FCT646CTSOC 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 CY74FCT646CTSOC reliable?
The price and inventory of CY74FCT646CTSOC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY74FCT646CTSOC is usually 5 days.
3.What payment methods are accepted for CY74FCT646CTSOC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY74FCT646CTSOC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CY74FCT646CTSOC?
CY74FCT646CTSOC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CY74FCT646CTSOC 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 CY74FCT646CTSOC?
For technical support, including CY74FCT646CTSOC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY74FCT646CTSOC requirements.
6.How does Aetrix verify that CY74FCT646CTSOC is sourced from the original manufacturer or authorized distributors?
All CY74FCT646CTSOC 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 CY74FCT646CTSOC meets industry standards.
7.What is the process for return or replacement of CY74FCT646CTSOC?
All CY74FCT646CTSOC units undergo pre-shipment inspection (PSI). If there is an issue with CY74FCT646CTSOC, 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 CY74FCT646CTSOC part is unused and in its original packaging.
Return procedure for CY74FCT646CTSOC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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