CD74HC688NS Equivalent & Substitute Parts

Part Overview

The CD74HC688NS is an 8-bit identity comparator manufactured by Texas Instruments, designed for magnitude comparison applications with active low output. This logic component performs A=B comparison operations and is housed in a 20-SOIC surface mount package. The CD74HC688NS is currently discontinued at DiGi Electronics, making identification of equivalent substitute parts essential for ongoing design support and procurement continuity.

Substiute Parts

CD74HC688NS

Texas InstrumentsIn Stock: 1055CD74HC688NS Datasheet

Current PartRFQ

CD74HC688NSR

Texas InstrumentsIn Stock: 4436CD74HC688NSR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CD74HC688NS is determined by strict equivalence across the following critical parameters:

Functional Parameters:

• 8-bit identity comparator architecture
• A=B output function
• Active low output logic level

Electrical Parameters:

• Supply voltage range: 2V ~ 6V
• Output current capability: 5.2mA (both high and low states)
• Propagation delay: 29ns @ 6V, 50pF load
• Quiescent current: 8 µA
• Operating temperature: -55°C ~ 125°C

Physical Parameters:

• Package type: 20-SOIC with 0.209" (5.30mm) width
• Surface mount mounting type

Compliance Parameters:

• ROHS3 compliance
• MSL rating: 1 (Unlimited)

The CD74HC688NSR qualifies as a direct substitute based on identical electrical specifications, functional characteristics, and package configuration. The primary distinction is packaging format (Tape & Reel versus individual packaging) and product status (Active versus Discontinued).

Parameter Comparison

Engineering Selection Recommendations

The CD74HC688NSR is a direct functional and electrical equivalent to the CD74HC688NS. All critical parameters—including bit width, output function, electrical characteristics, temperature range, and package dimensions—are identical.

Selection Basis:

The CD74HC688NSR is recommended for new designs and procurement due to its Active product status. The original CD74HC688NS is discontinued at DiGi Electronics, limiting future availability and support.

Packaging Consideration:

The CD74HC688NSR is supplied in Tape & Reel (TR) format, which is standard for high-volume manufacturing and automated assembly. If individual unit packaging is required, the TR format can be processed into individual components through standard component handling procedures.

Compliance Status:

Both parts maintain ROHS3 compliance and MSL Level 1 (Unlimited) rating, ensuring compatibility with modern manufacturing processes and long-term storage without moisture sensitivity constraints.

Frequently Asked Questions (FAQ)

Q: Can CD74HC688NSR be used as a direct replacement for CD74HC688NS in existing designs?

A: Yes. The CD74HC688NSR is electrically and functionally identical to the CD74HC688NS. All electrical parameters, output characteristics, and package dimensions match exactly. The only difference is packaging format (Tape & Reel versus individual) and product status (Active versus Discontinued).

Q: What is the difference between CD74HC688NS and CD74HC688NSR?

A: The primary differences are packaging format and product availability. CD74HC688NS uses individual packaging and is discontinued. CD74HC688NSR uses Tape & Reel packaging and is currently in active production. Electrical and functional specifications are identical.

Q: Is the 20-SOIC package compatible between both parts?

A: Yes. Both parts use the identical 20-SOIC package with 0.209" (5.30mm) width. PCB footprints, land patterns, and assembly processes are interchangeable.

Q: What are the key parameters that determine substitution eligibility?

A: Substitution eligibility is determined by: 8-bit identity comparator function, A=B output operation, active low output logic, 2V ~ 6V supply voltage range, 5.2mA output current capability, 29ns propagation delay at 6V with 50pF load, 8 µA quiescent current, -55°C to 125°C operating temperature, 20-SOIC package configuration, and ROHS3 compliance.

Q: Are there any compliance or certification differences?

A: No. Both parts maintain identical ROHS3 compliance status and MSL Level 1 (Unlimited) rating. No additional certifications or compliance considerations apply to the substitution.

Q: Can CD74HC688NSR be used in high-volume manufacturing?

A: Yes. The Tape & Reel packaging format of the CD74HC688NSR is optimized for automated assembly and high-volume production environments. This format is standard in modern manufacturing processes.