74HCT640DB,112 Equivalent & Substitute Parts

Part Overview

The 74HCT640DB,112 is a logic transceiver IC manufactured by NXP Semiconductors, designed for inverting signal transmission with 3-state output capability. This component features 1 element with 8 bits per element, operating across a 4.5V to 5.5V supply voltage range. The part is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

74HCT640DB,112

NXP SemiconductorsIn Stock: 89774HCT640DB,112 Datasheet

Current PartRFQ

CD74HCT640M

Texas InstrumentsIn Stock: 3271CD74HCT640M Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74HCT640DB,112 is determined by strict alignment of the following electrical and mechanical parameters:

Critical Substitution Parameters:

• Logic type: Transceiver, Inverting
• Number of elements: 1
• Bits per element: 8
• Output type: 3-State
• Output current capability: 6mA (high and low)
• Supply voltage range: 4.5V ~ 5.5V
• Series compatibility: 74HCT

Package Considerations: The 74HCT640DB,112 uses a 20-SSOP package. Substitute parts may employ alternative 20-pin surface mount packages (such as 20-SOIC) provided that pin configuration, electrical characteristics, and board-level compatibility remain functionally equivalent.

Compliance Requirements: All substitute parts must maintain ROHS3 compliance and MSL rating of 1 or better to ensure compatibility with modern manufacturing and storage protocols.

Parameter Comparison

Engineering Selection Recommendations

The CD74HCT640M from Texas Instruments qualifies as a direct functional substitute for the 74HCT640DB,112. Both components share identical logic functionality, electrical specifications, and compliance certifications. The CD74HCT640M offers the advantage of active product status, ensuring continued availability and manufacturing support.

The primary design consideration is package geometry. The CD74HCT640M employs a 20-SOIC package (0.295" width) compared to the 20-SSOP package (0.209" width) of the original part. This difference requires PCB layout verification to confirm footprint compatibility and clearance with adjacent components.

The CD74HCT640M supports an extended operating temperature range (-55°C to 125°C) compared to the original part (-40°C to 125°C), providing additional thermal margin for demanding applications.

Frequently Asked Questions (FAQ)

Q: Can the CD74HCT640M directly replace the 74HCT640DB,112 without circuit modification?

A: Electrical substitution is direct. Pin configuration and signal levels are identical. PCB layout modification is required due to package size difference (20-SOIC versus 20-SSOP).

Q: What is the primary difference between these two parts?

A: The main differences are product status (obsolete versus active), package type (SSOP versus SOIC), and operating temperature range (-40°C to 125°C versus -55°C to 125°C). Electrical functionality and output specifications are identical.

Q: Are both parts RoHS compliant?

A: Yes. Both the 74HCT640DB,112 and CD74HCT640M are ROHS3 compliant with MSL rating of 1 (unlimited moisture sensitivity protection).

Q: Does package size affect electrical performance?

A: No. Package type does not alter electrical characteristics, output current capability, or supply voltage requirements. Package selection is determined by PCB layout constraints and manufacturing capabilities.

Q: Is the extended temperature range of the CD74HCT640M beneficial for all applications?

A: The extended range (-55°C to 125°C versus -40°C to 125°C) provides additional thermal margin. Applications operating at lower temperatures benefit from this specification. Standard applications within -40°C to 125°C experience no functional difference.