My Inquiry
My Account
Texas Instruments CY74FCT821ATSOCT
- Part No.:
- CY74FCT821ATSOCT
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CY74FCT821ATSOCT.pdf
- Description:
- IC FF D-TYPE SNGL 10BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,181
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
CY74FCT821ATSOCT from Texas Instruments is a 10-bit positive-edge-triggered bus-interface register with 3-state outputs, designed for high-capacitance load drive and low-bus-loading operation in 5-V TTL-compatible systems. It features 6 ns propagation delay (tPLH/tPHL), 64 mA sink / 32 mA source output drive, Ioff support for partial-power-down mode, and edge-rate control for improved noise immunity.
For engineers reviewing the CY74FCT821ATSOCT datasheet, CY74FCT821ATSOCT pinout, CY74FCT821ATSOCT application, or CY74FCT821ATSOCT equivalent, this device is selected for high-IOL/IOH output port buffering, wide data/address bus expansion, and industrial control I/O interfacing where TTL-level compatibility and robust 3-state bus isolation are required.
Technical Context
This device implements ten independent D-type flip-flops synchronized to the rising edge of CP, with separate 3-state output enable (OE) controlling all Y outputs simultaneously. Its architecture supports simultaneous data latching and bus release without internal contention.
Edge-rate control circuitry actively limits slew rate to reduce simultaneous switching noise, while matched rise/fall times ensure clean signal transitions. The Ioff feature disables outputs when VCC = 0 V, blocking reverse current flow during partial power-down - critical for hot-swap and mixed-voltage system designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Propagation Delay (tPLH/tPHL) | 10 ns max at CL = 50 pF - enables reliable timing in 100-MHz bus cycles with margin |
| Output Drive Strength | 64 mA sink / 32 mA source - drives heavy capacitive loads (e.g., >100 pF buses) without signal degradation |
| Ioff Current | ±1 µA at VCC = 0 V - prevents backflow damage during partial power-down sequences |
| Input Voltage Thresholds | VIL = 0.8 V, VIH = 2.0 V - fully compatible with standard TTL logic levels |
| Supply Voltage Range | 4.75 V to 5.25 V - tight regulation ensures stable operation across industrial temperature range |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded and control applications |
| ESD Protection | 2000-V HBM, 200-V MM, 1000-V CDM - exceeds JEDEC 22 requirements for board-level robustness |
Pinout & Package
Package: 24-pin SOIC (DW), body width 7.5 mm, RoHS-compliant, moisture sensitivity level 1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Output Enable input | Active-low control: OE = L enables Y outputs; OE = H places all Y pins in high-impedance state |
| 2–11 (D0–D9) | Data inputs | Synchronous parallel data inputs latched on CP rising edge; CMOS/TTL-compatible voltage thresholds |
| 12 (GND) | Ground reference | Primary return path for all internal logic and output drivers; must be low-impedance |
| 13 (CP) | Clock input | Positive-edge-triggered register clock; data sampled only on low-to-high transition |
| 14–23 (Y0–Y9) | 3-state registered outputs | True (non-inverted) outputs reflecting latched D values when OE = L; high-Z when OE = H |
| 24 (VCC) | Power supply | +5 V nominal supply; decoupling capacitor required within 1 cm for noise suppression |
Key Features
| Feature | Design Value |
|---|---|
| Edge-Rate Control | Actively limits output slew rate to suppress simultaneous switching noise (SSN) on shared buses |
| Matched Rise/Fall Times | Ensures symmetrical signal edges (<1 ns skew), minimizing jitter and setup/hold violations |
| Ioff Partial-Power-Down Support | Blocks current flow between powered and unpowered sections in mixed-supply systems |
| TTL-Compatible Input/Output Levels | Accepts standard TTL VIH/VIL and delivers TTL VOH/VOL - eliminates level-shifting components |
| Low Input/Output Capacitance | Ci = 5–10 pF, Co = 9–12 pF - minimizes loading on driving sources and downstream receivers |
Applications
| Industrial PLC I/O Expansion | Memory Address Bus Buffering |
|---|---|
|
Use Scenario: Expanding digital I/O capacity in programmable logic controllers by adding parallel output ports for relay/solenoid control. IC Role / Device Role / Timing Role: Acts as a latch-and-drive interface between microcontroller GPIO and high-current field devices, synchronized to system clock. Use Value: Delivers 64 mA per output to directly drive industrial loads while maintaining bus isolation via 3-state control during idle cycles. |
Use Scenario: Buffering 10-bit segments of memory address buses in legacy 80x86 or Z80-based systems with long trace runs. IC Role / Device Role / Timing Role: Registers and re-drives address signals to maintain signal integrity across multi-load PCB traces. Use Value: 10 ns propagation delay and matched edge rates prevent address skew that could cause memory access errors. |
| Backplane Data Bus Interface | Test Equipment Digital Pattern Generator |
|
Use Scenario: Isolating and driving 10-bit data lanes on modular backplanes connecting CPU and peripheral modules. IC Role / Device Role / Timing Role: Provides controlled bus access using OE to prevent contention during module hot-swap or reset sequences. Use Value: Ioff protection ensures safe operation when one module is powered down while others remain active on shared bus lines. |
Use Scenario: Generating precise, synchronized 10-bit digital stimulus patterns for IC functional testing. IC Role / Device Role / Timing Role: Captures pattern data on CP edge and presents it via high-drive 3-state outputs under test controller OE command. Use Value: 32 mA source / 64 mA sink capability drives multiple DUT inputs simultaneously without external buffers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit registered bus-interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY74FCT821BTSOCT | Slower 7.5 ns max propagation delay; identical pinout, package, and Ioff functionality | Better suited for cost-sensitive industrial systems where timing margin allows relaxed speed | Select when system clock frequency ≤ 80 MHz and lower dynamic power is prioritized |
| CY74FCT821CTSOCT | Faster 6 ns max propagation delay; same SOIC-24 package and electrical interface | Required for high-speed data acquisition or real-time control loops demanding minimal latency | Choose when tPLH/tPHL < 7 ns is mandatory and full 100-MHz bus timing closure is needed |
Compared with CY74FCT821BTSOCT and CY74FCT821CTSOCT, the CY74FCT821ATSOCT offers balanced performance: faster than the 'B' variant for improved timing margin, yet more power-efficient than the 'C' variant due to optimized drive strength - ideal for mid-speed industrial interfaces requiring reliability over raw speed.
Availability
CY74FCT821ATSOCT is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, memory address bus buffering, and backplane data bus interface applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for CY74FCT821ATSOCT 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 expertise in industrial-grade interface and timing products.
The CY74FCT821ATSOCT belongs to TI's FCT logic family - engineered for robust 5-V TTL-compatible bus interfacing in industrial automation, test equipment, and legacy computing systems where noise immunity and partial-power-down safety are essential.
FAQ
What is the maximum clock frequency supported by CY74FCT821ATSOCT?
CY74FCT821ATSOCT does not specify a maximum clock frequency in its datasheet; instead, it guarantees timing parameters including 10 ns max tPLH/tPHL and 4 ns min tsu (setup time). Based on these, the device reliably operates up to approximately 80 MHz in typical 50-pF load conditions - sufficient for most industrial bus and control applications. System-level timing analysis must include board trace delays and load capacitance.
Does CY74FCT821ATSOCT support hot-swap or live-insertion?
Yes, CY74FCT821ATSOCT supports partial-power-down operation via its Ioff feature: when VCC = 0 V, Ioff limits reverse current to ±1 µA, preventing damage during hot-swap events. However, proper sequencing of OE deassertion before power removal and use of series resistors on Y lines are recommended for full hot-swap robustness in backplane applications.
Can CY74FCT821ATSOCT drive a 150-pF bus capacitance?
CY74FCT821ATSOCT is characterized for CL = 50 pF and 300 pF loads, with tPLH/tPHL increasing from 10 ns to 20 ns at 300 pF. While it can drive 150-pF loads, timing margins will degrade - expect ~15 ns propagation delay and potential edge rounding. For guaranteed 150-pF operation, verify signal integrity with oscilloscope measurements and consider adding series termination if ringing occurs.
Is CY74FCT821ATSOCT pin-compatible with older 74FCT821 variants?
Yes, CY74FCT821ATSOCT shares identical 24-pin SOIC (DW) pinout and function mapping with CY74FCT821BTSOCT and CY74FCT821CTSOCT - all three use the same D0–D9, CP, OE, Y0–Y9, VCC, and GND assignments. This allows direct substitution in existing layouts without PCB changes, provided timing and drive requirements are verified.
What is the purpose of the edge-rate control circuitry in CY74FCT821ATSOCT?
The edge-rate control circuitry in CY74FCT821ATSOCT actively limits the slew rate of output transitions to reduce simultaneous switching noise (SSN) on shared buses. This minimizes crosstalk and ground bounce in dense digital systems - especially critical in industrial environments with multiple high-drive devices sharing common return paths and long PCB traces.
CY74FCT821ATSOCT 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:
- Obsolete
- Function:
- Standard
- Type:
- D-Type
- Output Type:
- Tri-State, Non-Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 10
- Clock Frequency:
- -
- Max Propagation Delay @ V, Max CL:
- 20ns @ 5V, 300pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 32mA, 64mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 200 µA
- Input Capacitance:
- 5 pF
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
CY74FCT821ATSOCT FAQ
1.How can I place an order for CY74FCT821ATSOCT through Aetrix?
Please submit a Request for Quotation (RFQ) for CY74FCT821ATSOCT 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 CY74FCT821ATSOCT reliable?
The price and inventory of CY74FCT821ATSOCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY74FCT821ATSOCT is usually 5 days.
3.What payment methods are accepted for CY74FCT821ATSOCT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY74FCT821ATSOCT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CY74FCT821ATSOCT?
CY74FCT821ATSOCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CY74FCT821ATSOCT 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 CY74FCT821ATSOCT?
For technical support, including CY74FCT821ATSOCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY74FCT821ATSOCT requirements.
6.How does Aetrix verify that CY74FCT821ATSOCT is sourced from the original manufacturer or authorized distributors?
All CY74FCT821ATSOCT 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 CY74FCT821ATSOCT meets industry standards.
7.What is the process for return or replacement of CY74FCT821ATSOCT?
All CY74FCT821ATSOCT units undergo pre-shipment inspection (PSI). If there is an issue with CY74FCT821ATSOCT, 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 CY74FCT821ATSOCT part is unused and in its original packaging.
Return procedure for CY74FCT821ATSOCT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
CY74FCT821ATSOCT Tags
-
SN74HC74DR
Texas Instruments
-
SN74HC74PWR
Texas Instruments
-
74LVC1G74GT,115
Nexperia USA Inc.
-
SN74LVC2G74DCUR
Texas Instruments
-
CD4013BM96
Texas Instruments
-
SN74HCT273PWR
Texas Instruments
-
SN74LVC1G74DCUR
Texas Instruments
-
SN74HC574DWR
Texas Instruments
-
74LVC1G74DC,125
Nexperia USA Inc.
-
SN74HC273DWR
Texas Instruments
-
SN74HCT574DWR
Texas Instruments
-
SN74LVC1G74DCTR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
