CY74FCT821BTPC Equivalent & Substitute Parts

Part Overview

The CY74FCT821BTPC is a D-Type flip-flop logic integrated circuit manufactured by Texas Instruments, featuring 1 element with 10-bit capacity and tri-state, non-inverted output configuration. This component is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and procurement continuity. The part operates within the 74FCT logic series standard, designed for applications requiring positive edge-triggered flip-flop functionality in through-hole mounting configurations.

Substiute Parts

CY74FCT821BTPC

Texas InstrumentsIn Stock: 2187CY74FCT821BTPC Datasheet

Current PartRFQ

CY74FCT821BTSOC

Texas InstrumentsIn Stock: 1787CY74FCT821BTSOC Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CY74FCT821BTPC is determined by strict equivalence across the following critical parameters:

• Logic Function: D-Type flip-flop with 1 element, 10-bit configuration, positive edge trigger
• Output Configuration: Tri-state, non-inverted output
• Electrical Specifications: Supply voltage 4.75V ~ 5.25V, output current capability 32mA/64mA, quiescent current 200 µA
• Base Product Number: 74FCT821 (core functional designation)
• Compliance: ROHS3 compliant, REACH unaffected

The substitute part CY74FCT821BTSOC maintains functional and electrical equivalence to the main part while differing in mounting technology (surface mount versus through-hole) and package form factor (24-SOIC versus 24-DIP). Both parts share identical logic function, trigger characteristics, and core electrical parameters within their respective package constraints.

Parameter Comparison

Engineering Selection Recommendations

The CY74FCT821BTSOC serves as a direct functional substitute for the obsolete CY74FCT821BTPC. Both parts maintain identical logic function, electrical performance within their respective package constraints, and regulatory compliance status (ROHS3 compliant, REACH unaffected).

Selection between these parts depends on board-level design requirements:

• Through-hole applications requiring the original 24-DIP form factor must source remaining CY74FCT821BTPC inventory or redesign for surface-mount compatibility.
• New designs or redesigns should specify CY74FCT821BTSOC, which offers active product status and surface-mount advantages while maintaining functional equivalence.
• Propagation delay differences reflect package-dependent load conditions (6ns @ 50pF for DIP versus 15ns @ 5V, 300pF for SOIC) and do not indicate functional incompatibility.

Both parts comply with ROHS3 and REACH requirements, supporting equivalent environmental and regulatory qualification pathways.

Frequently Asked Questions (FAQ)

Q: Can CY74FCT821BTSOC directly replace CY74FCT821BTPC in existing through-hole designs?

A: Functionally, yes. Electrically and logically, the parts are equivalent. However, CY74FCT821BTSOC uses surface-mount packaging (24-SOIC), requiring board redesign or adapter solutions for through-hole PCB layouts. Direct socket substitution is not possible without mechanical adaptation.

Q: What is the significance of the propagation delay difference (6ns versus 15ns)?

A: The propagation delay values reflect different measurement conditions tied to package parasitics. The 6ns specification for CY74FCT821BTPC is measured at 50pF load, while the 15ns for CY74FCT821BTSOC is measured at 5V supply with 300pF load. Both values are within the 74FCT series performance envelope and do not indicate functional degradation.

Q: Why is CY74FCT821BTPC listed as obsolete?

A: The CY74FCT821BTPC is obsolete due to market transition toward surface-mount technology. CY74FCT821BTSOC represents the active product continuation within the same 74FCT821 base product family.

Q: Are there any compliance or certification differences between these parts?

A: No. Both parts are ROHS3 compliant and REACH unaffected, supporting identical environmental and regulatory qualification requirements.

Q: What are the key parameters that determine substitution eligibility?

A: Substitution is determined by equivalence in logic function (D-Type flip-flop, 1 element, 10-bit), output configuration (tri-state, non-inverted), trigger type (positive edge), supply voltage range (4.75V ~ 5.25V), output current capability (32mA/64mA), and base product number (74FCT821). Package form factor and mounting technology are design-dependent considerations, not functional barriers.