PI74FCT646ATQ Equivalent & Substitute Parts

Part Overview

The PI74FCT646ATQ is a non-inverting transceiver logic IC manufactured by Diodes Incorporated, designed for 8-bit bidirectional data transfer with 3-state output capability. Operating within the 4.75V to 5.25V supply range, this component is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing design requirements and production continuity.

Substiute Parts

PI74FCT646ATQ

Diodes IncorporatedIn Stock: 910PI74FCT646ATQ Datasheet

Current PartRFQ

CY74FCT646ATQCT

Texas InstrumentsIn Stock: 2363CY74FCT646ATQCT Datasheet

MFR RecommendedRFQ

CY74FCT646CTQCT

Texas InstrumentsIn Stock: 1081CY74FCT646CTQCT Datasheet

MFR RecommendedRFQ

74FCT543ATQG

Renesas Electronics CorporationIn Stock: 132974FCT543ATQG Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the PI74FCT646ATQ are classified based on strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

• Logic Type: Transceiver, Non-Inverting
• Number of Elements: 1
• Number of Bits per Element: 8
• Output Type: 3-State
• Voltage - Supply: 4.75V ~ 5.25V
• Operating Temperature: -40°C ~ 85°C (TA)
• Package / Case: 24-SSOP (0.154", 3.90mm Width)
• Mounting Type: Surface Mount

Substitute Classification:

MFR Recommended Substitutes meet all primary electrical parameters and are actively supported by their manufacturers. These parts demonstrate full functional equivalence with enhanced compliance certifications.

Parametric Equivalents match all primary electrical and mechanical parameters but may differ in product lifecycle status or output current specifications within acceptable operational ranges.

Parameter Comparison

Engineering Selection Recommendations

CY74FCT646ATQCT (Texas Instruments) is the primary recommended substitute. This part maintains full electrical equivalence across all critical parameters while offering active product status and ROHS3 compliance. The increased output high current specification (32mA versus 15mA) provides enhanced drive capability without compromising circuit compatibility. Moisture sensitivity level MSL-2 requires standard handling procedures for a one-year shelf life.

CY74FCT646CTQCT (Texas Instruments) provides equivalent electrical performance and compliance characteristics but carries discontinued status at DiGi Electronics, limiting long-term availability assurance.

74FCT543ATQG (Renesas Electronics Corporation) matches the original output current specifications (15mA, 64mA) and maintains MSL-1 moisture sensitivity rating. Product status is Last Time Buy, indicating limited future availability. This part is suitable for applications where output current specifications must remain unchanged from the original design.

For new designs and production continuity, CY74FCT646ATQCT is the preferred selection based on active product status and regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can CY74FCT646ATQCT replace PI74FCT646ATQ in existing designs?

A: Yes. Both parts share identical logic type, element count, bit width, output type, supply voltage range, operating temperature range, and package specifications. The increased output high current (32mA versus 15mA) is a performance enhancement that does not create compatibility issues in standard applications.

Q: What is the significance of the MSL rating difference between PI74FCT646ATQ (MSL-1) and CY74FCT646ATQCT (MSL-2)?

A: MSL-1 indicates unlimited shelf life under controlled storage conditions. MSL-2 requires component use within one year of manufacture under specified humidity and temperature conditions. CY74FCT646ATQCT requires standard moisture control procedures during storage and handling but presents no functional limitation for circuit operation.

Q: Why is 74FCT543ATQG classified as a parametric equivalent rather than a direct substitute?

A: While 74FCT543ATQG matches all primary electrical and mechanical parameters, it carries Last Time Buy status, indicating discontinued production. This classification reflects availability constraints rather than functional incompatibility.

Q: Are there package compatibility considerations between these substitutes?

A: All substitute parts use the 24-SSOP package with identical physical dimensions (0.154", 3.90mm Width). Direct PCB footprint compatibility is confirmed across all listed alternatives.

Q: What compliance advantages do the Texas Instruments substitutes offer?

A: Both CY74FCT646ATQCT and CY74FCT646CTQCT carry ROHS3 compliance certification, meeting current regulatory requirements for electronic component manufacturing and distribution. The original PI74FCT646ATQ is RoHS non-compliant.