74HC688D,652 8-Bit Identity Comparator Equivalent & Substitute Parts

Part Overview

The 74HC688D,652 is an 8-bit magnitude comparator with active-low output manufactured by Nexperia USA Inc. This logic IC performs identity comparison operations, outputting an A=B signal when input conditions are met. The device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Substiute Parts

74HC688D,652

Nexperia USA Inc.In Stock: 107474HC688D,652 Datasheet

Current PartRFQ

CD74HC688M

Harris CorporationIn Stock: 3085CD74HC688M Datasheet

UpgradeRFQ

CD74HC688M96

Texas InstrumentsIn Stock: 2916CD74HC688M96 Datasheet

UpgradeRFQ

SN74HC688DWR

Texas InstrumentsIn Stock: 3380SN74HC688DWR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 74HC688D,652 are qualified based on the following electrical and mechanical parameters:

Core Compatibility Criteria:

• Identical bit width: 8-bit comparator
• Identical output configuration: Active Low, A=B function
• Identical supply voltage range: 2V ~ 6V
• Identical output current specifications: 5.2mA / 5.2mA
• Identical quiescent current: 8 µA
• Identical package type: 20-SOIC form factor
• Surface mount mounting type

Substitution Categories:

Upgrade Parts (Enhanced specifications or active product status):

• CD74HC688M (Harris Corporation) – Obsolete status, RoHS non-compliant, extended temperature range (-55°C ~ 125°C)
• CD74HC688M96 (Texas Instruments) – Active product status, ROHS3 compliant, extended temperature range (-55°C ~ 125°C)

Similar Parts (Active alternatives with minor specification variations):

• SN74HC688DWR (Texas Instruments) – Active product status, ROHS3 compliant, restricted temperature range (-40°C ~ 85°C), slightly higher propagation delay (36ns vs 29ns)

All substitute parts maintain the 74HC series base product designation and are electrically and mechanically compatible within the specified parameter tolerances.

Parameter Comparison

Engineering Selection Recommendations

For RoHS3 Compliant Applications: CD74HC688M96 is the primary recommendation. This Texas Instruments part maintains ROHS3 compliance, active product status, and identical electrical specifications to the main part. The extended operating temperature range (-55°C ~ 125°C) provides additional thermal margin compared to the original specification.

For Extended Temperature Range Requirements: Both CD74HC688M and CD74HC688M96 support the expanded temperature range of -55°C ~ 125°C, compared to the main part's -40°C ~ 125°C specification. CD74HC688M96 is preferred due to active product status and RoHS compliance.

For Restricted Temperature Applications: SN74HC688DWR is suitable for applications limited to -40°C ~ 85°C operating range. This part is active, RoHS3 compliant, and carries MSL 1 rating. The propagation delay specification (36ns) is slightly higher than the main part (29ns) and must be evaluated against timing-critical circuit requirements.

For Legacy System Maintenance: CD74HC688M provides functional equivalence but carries RoHS non-compliance status and obsolete product designation. This part is suitable only for non-regulated applications or systems where RoHS compliance is not required.

Frequently Asked Questions (FAQ)

Q: Can CD74HC688M96 be used as a direct replacement for 74HC688D,652?

A: Yes. CD74HC688M96 is electrically and mechanically compatible. Both devices share identical bit width (8-bit), output configuration (active low, A=B function), supply voltage range (2V ~ 6V), output current (5.2mA), quiescent current (8 µA), and package type (20-SOIC). The extended temperature range and active product status make it a superior choice for new designs.

Q: What is the difference between the upgrade parts and the similar part?

A: Upgrade parts (CD74HC688M and CD74HC688M96) maintain the original 29ns propagation delay specification. The similar part (SN74HC688DWR) has a slightly higher propagation delay of 36ns at 6V with 50pF load. Additionally, SN74HC688DWR has a restricted operating temperature range (-40°C ~ 85°C) compared to the upgrade parts (-55°C ~ 125°C).

Q: Is the 20-SOIC package identical across all substitute parts?

A: Yes. All substitute parts use the 20-SOIC package with 0.295" width and 7.50mm height. PCB footprints and mounting procedures are identical.

Q: Which substitute part should be selected for new product designs?

A: CD74HC688M96 is recommended for new designs. It is manufactured by Texas Instruments, maintains active product status, is ROHS3 compliant, and carries unlimited moisture sensitivity level (MSL 1) rating. These factors ensure long-term availability and regulatory compliance.

Q: Are there any timing considerations when substituting SN74HC688DWR?

A: Yes. SN74HC688DWR has a maximum propagation delay of 36ns compared to 29ns for the main part and other upgrade parts. In timing-critical applications, this 7ns difference must be evaluated against circuit margin requirements and system clock specifications.

Q: What is the RoHS compliance status of each substitute?

A: CD74HC688M96 and SN74HC688DWR are ROHS3 compliant. CD74HC688M is RoHS non-compliant. The main part (74HC688D,652) is ROHS3 compliant. For regulated applications, only ROHS3 compliant parts should be selected.