74HC646D,652 Equivalent & Substitute Parts

Part Overview

The 74HC646D,652 is a non-inverting transceiver IC manufactured by NXP USA Inc., designed for 8-bit data transmission with 3-state output capability. This component operates across a 2V to 6V supply voltage range and is housed in a 24-SOIC package. The part is currently classified as obsolete, making identification of functionally equivalent substitutes essential for ongoing system support and new design implementations.

Substiute Parts

74HC646D,652

NXP USA Inc.In Stock: 90374HC646D,652 Datasheet

Current PartRFQ

MC74AC646DWR2G

onsemiIn Stock: 22179MC74AC646DWR2G 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 eligibility for the 74HC646D,652 is determined by the following critical parameters:

• Logic Type: Transceiver, Non-Inverting
• Number of Elements: 1
• Number of Bits per Element: 8
• Output Type: 3-State
• Package / Case: 24-SOIC (0.295", 7.50mm Width)
• Voltage - Supply: 2V ~ 6V

Substitute parts must maintain identical functional architecture (1 element, 8-bit transceiver with 3-state output) and physical compatibility (24-SOIC package). Output current specifications may vary within acceptable design margins. Operating temperature ranges and product status are secondary considerations that may affect application suitability but do not preclude functional substitution.

Parameter Comparison

Engineering Selection Recommendations

SN74HC646DWR (Texas Instruments) is the primary substitute for new designs and ongoing support. This part maintains identical electrical specifications to the original 74HC646D,652, including output current (7.8mA), supply voltage range (2V ~ 6V), and moisture sensitivity level (MSL 1). The component carries Active product status, ensuring long-term availability and supply chain stability. ROHS3 compliance is maintained.

SN74HC646DW (Texas Instruments) provides an alternative with equivalent electrical performance. This part is classified as Last Time Buy, indicating limited future availability. It is suitable for legacy system repairs where supply constraints are not critical.

MC74AC646DWR2G (onsemi) offers functional substitution with elevated output current specifications (24mA versus 7.8mA). This part operates within the same supply voltage range and package footprint. The 74AC series exhibits higher drive capability, which may benefit applications requiring increased output current. However, the operating temperature range is reduced to -40°C ~ 85°C, and moisture sensitivity is elevated to MSL 3 (168 Hours). This substitute is suitable only when higher output current is required and the reduced temperature range and MSL rating are acceptable for the application.

Frequently Asked Questions (FAQ)

Q: Can the MC74AC646DWR2G replace the 74HC646D,652 in all applications?

A: The MC74AC646DWR2G provides functional substitution at the logic level but introduces three design considerations. The output current is increased to 24mA (compared to 7.8mA in the original), which may affect circuit behavior in current-limited designs. The operating temperature range is narrowed to -40°C ~ 85°C (versus -40°C ~ 125°C), making it unsuitable for high-temperature applications. The moisture sensitivity level is elevated to MSL 3, requiring stricter handling and storage protocols. Substitution is valid only when these parameter differences are acceptable for the specific application.

Q: Are all substitute parts pin-compatible with the 74HC646D,652?

A: All listed substitutes use the 24-SOIC package with identical physical dimensions (0.295", 7.50mm Width). Pin compatibility is maintained across all substitutes at the mechanical level. Electrical compatibility is confirmed through matching logic type, element count, bit width, and output type specifications.

Q: What is the difference between the 74HC and 74AC series?

A: Both series implement identical logic functions and pin configurations. The primary difference is output drive capability. The 74AC series (represented by MC74AC646DWR2G) provides higher output current (24mA) compared to the 74HC series (7.8mA). The 74AC series also operates at a reduced maximum temperature of 85°C versus 125°C for 74HC. Series selection depends on application requirements for output current and operating temperature range.

Q: Is the SN74HC646DWR suitable for new product designs?

A: Yes. The SN74HC646DWR carries Active product status, indicating current production and long-term availability. This part is the recommended choice for new designs requiring the 74HC646 transceiver function. It maintains full electrical and environmental compliance (ROHS3, REACH Unaffected) and is available in standard packaging formats (Tape & Reel).

Q: What does MSL 1 (Unlimited) mean compared to MSL 3 (168 Hours)?

A: Moisture Sensitivity Level (MSL) defines the maximum time a component can be exposed to ambient conditions (typically 30°C, 85% relative humidity) before requiring baking. MSL 1 (Unlimited) indicates no time restriction, allowing extended shelf storage without special handling. MSL 3 (168 Hours) limits exposure to 168 hours, after which the component must be baked to remove absorbed moisture before soldering. This affects supply chain logistics and manufacturing procedures.