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Texas Instruments CY74FCT646ATSOCT
- Part No.:
- CY74FCT646ATSOCT
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CY74FCT646ATSOCT.pdf
- Description:
- IC TXRX NON-INVERT 5.25V 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,997
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Product details
Overview
CY74FCT646ATSOCT from Texas Instruments is an 8-bit registered transceiver with 3-state outputs, designed for bidirectional data routing between A and B buses in TTL- and FCT-compatible digital systems. It features independent A/B registers, edge-rate controlled outputs (reducing noise), Ioff partial-power-down support, and 64 mA sink / 32 mA source drive capability at 5 V. It is used in bus isolation, register-based data multiplexing, and legacy system interface bridging.
For engineers reviewing the CY74FCT646ATSOCT datasheet, CY74FCT646ATSOCT pinout, CY74FCT646ATSOCT application, or CY74FCT646ATSOCT equivalent, key selection criteria include its 6.3 ns propagation delay (max), 3.3 V typical VOH, matched rise/fall times, dual-clock control (CPAB/CPBA), and SOIC-24 package compatibility with industrial temperature range (–40°C to +85°C).
Technical Context
The CY74FCT646ATSOCT implements a dual-bus registered transceiver architecture with separate clock inputs (CPAB, CPBA) enabling independent latching of A- or B-bus data on rising edges. Its DIR and G inputs configure real-time or stored-data transfer direction and 3-state output enable/disable states.
It integrates edge-rate control circuitry to limit slew rate and suppress switching noise, supports Ioff protection during partial power-down, and maintains full TTL input/output voltage compatibility (VIH = 2 V min, VOL = 0.55 V max at IOL = 64 mA). The device operates within 4.75–5.25 V supply range and delivers 1.5–6.3 ns propagation delays depending on signal path and timing condition.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | FCT (Fast CMOS TTL-compatible), 5 V only |
| Bus Width | 8-bit bidirectional with independent A and B registers |
| Max Propagation Delay | 6.3 ns (A↔B path, CPAB/CPBA→output, TA = 85°C) |
| Output Drive | 64 mA sink / 32 mA source at VCC = 5 V - sufficient for driving multiple TTL loads |
| Supply Voltage Range | 4.75 V to 5.25 V - tight regulation required for stable timing and noise margin |
| Ioff Support | Yes - prevents backflow current when VCC = 0 V, enabling safe hot-insertion and partial power-down |
| ESD Protection | 2000-V HBM, 200-V MM, 1000-V CDM - meets JEDEC JESD22 standards for robust handling |
Pinout & Package
Package: SOIC-24 (DW), 15.4 mm × 7.5 mm body, 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, MSL Level-1 (unlimited reflow).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 inputs/outputs | Data register A port - bidirectional I/O; driven by B bus or internal A register |
| 9, 10, 11, 13, 14, 15, 16, 17 | B1–B8 inputs/outputs | Data register B port - bidirectional I/O; driven by A bus or internal B register |
| 12 | GND | Ground reference for all logic and power domains |
| 24 | VCC | 5 V supply input - must be decoupled locally per high-speed digital practice |
| 18 | G | Output-enable control - high = 3-state (high-Z), low = active output |
| 19 | DIR | Direction control - low = B→A transfer, high = A→B transfer (when G = low) |
| 20 | CPAB | Active-high clock for latching A-bus data into B register |
| 21 | CPBA | Active-high clock for latching B-bus data into A register |
| 22 | SAB | Selects A-bus data source - low = real-time A, high = stored A register |
| 23 | SBA | Selects B-bus data source - low = real-time B, high = stored B register |
Key Features
| Feature | Design Value |
|---|---|
| Edge-rate controlled outputs | Reduces simultaneous switching noise (SSN) and EMI without external series resistors |
| Independent A/B register clocks (CPAB/CPBA) | Enables asynchronous latching of data from either bus - critical for pipeline staging and bus arbitration |
| Ioff partial-power-down protection | Disables outputs and blocks current flow when VCC = 0 V - essential for hot-swap and multi-rail systems |
| Matched rise/fall times | Minimizes duty-cycle distortion in clock/data paths - improves setup/hold margin in synchronous designs |
| TTL-compatible input thresholds | VIH = 2 V min, VIL = 0.8 V max - ensures interoperability with legacy 5 V TTL, LSTTL, and earlier FCT devices |
Applications
| Industrial PLC Backplane Interface | Legacy System Bus Isolation |
|---|---|
|
Use Scenario: Interfacing microcontroller-based I/O modules to a 5 V parallel backplane with mixed timing domains and noise-sensitive analog sections. IC Role / Device Role / Timing Role: Registered transceiver providing synchronized, noise-suppressed data transfer between isolated A and B segments while supporting partial power-down during module sleep. Use Value: Eliminates need for discrete buffers and RC filters; 6.3 ns delay enables 80+ MHz bus operation; Ioff prevents backfeed during hot-swap maintenance. |
Use Scenario: Bridging a vintage 80C88 CPU bus to modern FPGA-based peripheral controllers in retro-computing or test equipment upgrades. IC Role / Device Role / Timing Role: Bidirectional bus repeater with latch capability - stores CPU address/data during wait states and forwards it to peripherals without skew. Use Value: Matches TTL voltage levels and drive strength; 3-state outputs prevent bus contention; SAB/SBA controls allow mixing real-time and registered data streams. |
| Automotive Body Control Module | Test Equipment Data Multiplexer |
|
Use Scenario: Managing communication between multiple sensor clusters and a central MCU in a 12 V automotive environment with strict EMC requirements. IC Role / Device Role / Timing Role: Noise-hardened bus transceiver isolating CAN/LIN subsystems from main diagnostic bus - operated in isolation mode (G = high) with selective register storage. Use Value: Edge-rate control reduces radiated emissions; 2000-V HBM ESD rating withstands assembly and field handling; –40°C to +85°C rating meets AEC-Q100 Grade 3 thermal profile. |
Use Scenario: Routing stimulus/response signals between DUT and ATE in automated functional testers requiring precise timing alignment across 8-bit data lanes. IC Role / Device Role / Timing Role: Registered data multiplexer - captures DUT outputs on CPAB edge, holds them, then forwards to tester logic on CPBA edge with deterministic latency. Use Value: 1.5 ns min tPLH/tPHL ensures sub-ns timing resolution; matched rise/fall preserves pulse symmetry; 50 pF load-driven specs match standard ATE termination. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar registered transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY74FCT646TTSOCT | Slower speed grade: 9 ns max propagation delay vs. 6.3 ns; identical pinout, drive, and feature set | Lower-cost option for non-critical timing paths where >100 MHz bus operation is not required | Select when timing budget allows ≥9 ns delay and cost sensitivity outweighs performance margin |
| CY74FCT646CTSOCT | Faster speed grade: 5.4 ns max propagation delay; same SOIC-24 package and electrical specs | Required for high-speed backplanes or systems demanding <8 ns clock-to-output timing | Choose when operating frequency exceeds 100 MHz or when tighter setup/hold margins are needed |
Compared with CY74FCT646ATSOCT, the T-version trades speed for cost in legacy interfaces, while the C-version delivers best-in-class timing for demanding synchronous buses - all three share identical register architecture, Ioff, and noise-control features.
Availability
CY74FCT646ATSOCT is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, legacy system upgrades, and automated test equipment requiring stable component supply across extended temperature and long-lifecycle programs.
Supply support for CY74FCT646ATSOCT 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 decades of heritage in high-reliability 5 V logic families.
CY74FCT646ATSOCT belongs to TI's FCT logic portfolio, engineered for noise-immune, TTL-compatible bus interfacing in industrial, automotive, and test instrumentation applications where signal integrity and power-down safety are critical.
FAQ
What is the maximum operating frequency supported by CY74FCT646ATSOCT?
CY74FCT646ATSOCT does not specify a maximum clock frequency directly, but its 6.3 ns maximum propagation delay (tPLH/tPHL) and 2 ns minimum pulse width (tw) imply reliable operation up to approximately 80 MHz in synchronous bus applications. Timing margins must account for setup/hold (tsu = 2 ns, th = 1.5 ns) and board-level signal integrity.
Does CY74FCT646ATSOCT support mixed-voltage operation (e.g., 3.3 V inputs with 5 V supply)?
No. CY74FCT646ATSOCT is a 5 V-only device with VIH = 2 V min and VIL = 0.8 V max - it accepts 3.3 V logic-high signals safely, but is not designed for 3.3 V supply operation. Its absolute maximum ratings prohibit VCC below 4.75 V, and output VOH is specified only at 4.75–5.25 V.
How does the Ioff feature function in CY74FCT646ATSOCT during partial power-down?
In CY74FCT646ATSOCT, Ioff disables all outputs when VCC = 0 V, limiting leakage current to ±1 µA even if A or B bus voltages reach 4.5 V. This prevents damaging reverse current flow through the device, enabling safe hot-plug operation and isolation of powered-down subsystems in multi-rail systems.
Can CY74FCT646ATSOCT operate in transparent (non-registered) mode?
Yes. When CPAB and CPBA are held static (not clocked), and DIR/G are asserted to enable real-time transfer, CY74FCT646ATSOCT passes data directly between A and B buses without latching - functioning as a standard 3-state transceiver. SAB/SBA inputs determine whether real-time or registered data is selected at outputs.
What is the thermal resistance (θJA) of CY74FCT646ATSOCT in SOIC-24 package?
The SOIC-24 (DW) package for CY74FCT646ATSOCT has a specified junction-to-ambient thermal resistance (θJA) of 46°C/W under standard JEDEC test conditions. This value assumes a 1-inch² copper pad with two vias; actual PCB layout significantly impacts thermal performance in high-current or high-density applications.
CY74FCT646ATSOCT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74FCT
- Package/Case:
- 24-SOIC (0.295", 7.50mm 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-SOIC
CY74FCT646ATSOCT FAQ
1.How can I place an order for CY74FCT646ATSOCT through Aetrix?
Please submit a Request for Quotation (RFQ) for CY74FCT646ATSOCT 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 CY74FCT646ATSOCT reliable?
The price and inventory of CY74FCT646ATSOCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY74FCT646ATSOCT is usually 5 days.
3.What payment methods are accepted for CY74FCT646ATSOCT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY74FCT646ATSOCT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CY74FCT646ATSOCT?
CY74FCT646ATSOCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CY74FCT646ATSOCT 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 CY74FCT646ATSOCT?
For technical support, including CY74FCT646ATSOCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY74FCT646ATSOCT requirements.
6.How does Aetrix verify that CY74FCT646ATSOCT is sourced from the original manufacturer or authorized distributors?
All CY74FCT646ATSOCT 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 CY74FCT646ATSOCT meets industry standards.
7.What is the process for return or replacement of CY74FCT646ATSOCT?
All CY74FCT646ATSOCT units undergo pre-shipment inspection (PSI). If there is an issue with CY74FCT646ATSOCT, 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 CY74FCT646ATSOCT part is unused and in its original packaging.
Return procedure for CY74FCT646ATSOCT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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