SN74HC688N Equivalent & Substitute Parts

Part Overview

The SN74HC688N is an 8-bit identity comparator manufactured by Texas Instruments, designed to compare two 8-bit binary words and output an active-low signal when the inputs are equal. This component is classified as a logic IC with through-hole mounting in a 20-DIP package. The product maintains active status with full RoHS3 compliance and REACH unaffected certification. Substitute parts may be required due to inventory constraints, manufacturing discontinuation, or specific application requirements related to packaging, voltage specifications, or propagation delay characteristics.

Substiute Parts

SN74HC688N

Texas InstrumentsIn Stock: 7729SN74HC688N Datasheet

Current PartRFQ

74HCT02D,653

Nexperia USA Inc.In Stock: 899474HCT02D,653 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The identified substitute part 74HCT02D,653 is a NOR gate logic IC manufactured by Nexperia USA Inc. Substitution analysis is based on the following critical parameters:

Substitution Criteria:

• Logic family compatibility (74HC/74HCT series)
• Supply voltage range overlap
• Propagation delay performance
• Output current drive capability
• Operating temperature range
• RoHS3 compliance status
• REACH unaffected certification

The 74HCT02D,653 operates within a narrower supply voltage range (4.5V ~ 5.5V) compared to the SN74HC688N (2V ~ 6V). This represents a functional constraint for applications requiring operation below 4.5V. However, the substitute demonstrates superior propagation delay performance (19ns @ 4.5V, 50pF versus 36ns @ 6V, 50pF) and lower quiescent current (2 µA maximum versus 8 µA), making it suitable for timing-critical or power-constrained applications operating within its voltage specification.

Parameter Comparison

Engineering Selection Recommendations

Both the SN74HC688N and 74HCT02D,653 maintain active product status with full RoHS3 compliance and REACH unaffected certification, qualifying both for current design implementations. Selection between these components depends on application-specific constraints:

SN74HC688N is appropriate for applications requiring extended supply voltage operation (2V ~ 6V range), through-hole PCB assembly, or designs with lower operating temperature limits (-40°C ~ 85°C).

74HCT02D,653 is suitable for applications operating within the 4.5V ~ 5.5V supply range, surface-mount assembly processes, designs benefiting from reduced propagation delay, or systems requiring extended operating temperature range (-40°C ~ 125°C).

Both components carry equivalent regulatory compliance certifications and are suitable for direct component selection based on stated electrical and mechanical requirements.

Frequently Asked Questions (FAQ)

Q: Can the 74HCT02D,653 directly replace the SN74HC688N in all applications?

A: Direct substitution is limited by supply voltage range and package type. The 74HCT02D,653 operates only within 4.5V ~ 5.5V, whereas the SN74HC688N supports 2V ~ 6V. Additionally, the 74HCT02D,653 uses surface-mount packaging (14-SOIC) while the SN74HC688N uses through-hole packaging (20-DIP), requiring different PCB assembly methods.

Q: What are the key electrical differences between these parts?

A: The 74HCT02D,653 provides faster propagation delay (19ns versus 36ns) and lower quiescent current (2 µA maximum versus 8 µA). However, it operates within a narrower supply voltage range and delivers slightly lower output current (4mA versus 5.2mA).

Q: Are both parts suitable for new designs?

A: Yes. Both components maintain active product status with current RoHS3 compliance and REACH unaffected certification, making them appropriate for new design implementations.

Q: What packaging considerations apply to substitution?

A: The SN74HC688N uses through-hole 20-DIP packaging for traditional PCB assembly, while the 74HCT02D,653 uses surface-mount 14-SOIC packaging. PCB layout and assembly process compatibility must be verified before substitution.

Q: How do operating temperature ranges compare?

A: The SN74HC688N operates from -40°C to 85°C, while the 74HCT02D,653 extends to 125°C maximum. Applications requiring operation above 85°C must use the 74HCT02D,653 or identify alternative components.