74HC646D,653 Equivalent & Substitute Parts

Part Overview

The 74HC646D,653 is a non-inverting transceiver logic integrated circuit manufactured by NXP USA Inc. in a 24-SO surface mount package. This component functions as a single-element, 8-bit transceiver with 3-state output capability, operating across a 2V to 6V supply voltage range. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity.

Substiute Parts

74HC646D,653

NXP USA Inc.In Stock: 104474HC646D,653 Datasheet

Current PartRFQ

74ACT11245DWR

Texas InstrumentsIn Stock: 89774ACT11245DWR Datasheet

MFR RecommendedRFQ

SN74HC646DW

Texas InstrumentsIn Stock: 2409SN74HC646DW Datasheet

MFR RecommendedRFQ

SN74HC646DWR

Texas InstrumentsIn Stock: 3982SN74HC646DWR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74HC646D,653 is determined by the following critical parameters:

Core Functional Requirements:

• Logic type: Transceiver, Non-Inverting
• Number of elements: 1
• Bits per element: 8
• Output type: 3-State
• Package / Case: 24-SOIC (0.295", 7.50mm Width)
• Mounting type: Surface Mount

Electrical Compatibility Criteria:

• Supply voltage range must accommodate the original 2V ~ 6V specification or provide overlap
• Output current capability (7.8mA minimum for 74HC series)
• Operating temperature range must support -40°C minimum

Compliance Requirements:

• RoHS3 compliance
• MSL rating of 1 (Unlimited)

The substitute parts listed below meet these core requirements while maintaining functional and mechanical compatibility with the 74HC646D,653.

Parameter Comparison

Engineering Selection Recommendations

SN74HC646DWR (Recommended Primary Substitute)

The SN74HC646DWR from Texas Instruments is the preferred substitute for the 74HC646D,653. This part maintains identical electrical specifications (2V ~ 6V supply, 7.8mA output current) and mechanical compatibility (24-SOIC package). The SN74HC646DWR holds Active product status, ensuring long-term availability and supply chain stability. RoHS3 compliance and MSL 1 rating match the original specification. Tape & Reel packaging supports automated assembly processes.

SN74HC646DW (Secondary Substitute)

The SN74HC646DW provides equivalent electrical and mechanical compatibility with Last Time Buy status. This part is suitable for applications where existing inventory can support near-term demand. Tube packaging may require manual handling in assembly operations compared to Tape & Reel format.

74ACT11245DWR (Alternative for Higher Output Current Requirements)

The 74ACT11245DWR from Texas Instruments offers increased output current capability (24mA versus 7.8mA) within a compatible 24-SOIC package. This substitute is applicable only when designs require higher drive current. The supply voltage range is restricted to 4.5V ~ 5.5V, limiting compatibility to systems operating within this narrower window. Active product status ensures availability.

Frequently Asked Questions (FAQ)

Q: Can the 74ACT11245DWR directly replace the 74HC646D,653 in all applications?

A: The 74ACT11245DWR is functionally compatible but operates within a narrower supply voltage range (4.5V ~ 5.5V versus 2V ~ 6V). Direct substitution is only appropriate for designs operating within the 4.5V ~ 5.5V window. The increased output current (24mA) is beneficial for high-drive applications but not required for standard 74HC646 designs.

Q: What is the difference between SN74HC646DW and SN74HC646DWR?

A: Both parts are electrically and mechanically identical. The primary difference is packaging format: SN74HC646DW is supplied in Tube packaging, while SN74HC646DWR is supplied in Tape & Reel (TR) format. Tape & Reel packaging is optimized for automated assembly processes, whereas Tube packaging is suitable for manual handling and lower-volume applications.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (SN74HC646DW, SN74HC646DWR, and 74ACT11245DWR) are RoHS3 compliant with MSL 1 (Unlimited) rating, matching the original 74HC646D,653 specification.

Q: Why is the operating temperature range different for some substitutes?

A: The SN74HC646DW and SN74HC646DWR operate to -40°C ~ 85°C, compared to the original -40°C ~ 125°C. This represents a reduced upper temperature limit. Applications requiring operation above 85°C must retain the original 74HC646D,653 or identify alternative solutions outside this substitute group.

Q: Is the 24-SOIC package footprint identical across all parts?

A: Yes. All substitute parts use the 24-SOIC (0.295", 7.50mm Width) package, ensuring mechanical and PCB footprint compatibility with the original 74HC646D,653 design.