CD74HCT166MT Equivalent & Substitute Parts

Part Overview

The CD74HCT166MT is an 8-bit parallel-in/serial-out shift register manufactured by Texas Instruments, housed in a 16-SOIC surface mount package. This component is classified as discontinued at DiGi Electronics, making identification of equivalent and substitute parts essential for ongoing design support and production continuity. The part operates within the 74HCT logic family, which maintains compatibility across multiple manufacturers through standardized electrical and mechanical specifications.

Substiute Parts

CD74HCT166MT

Texas InstrumentsIn Stock: 878CD74HCT166MT Datasheet

Current PartRFQ

CD74HCT166M96

Texas InstrumentsIn Stock: 9435CD74HCT166M96 Datasheet

Parametric EquivalentRFQ

74HC85D,653

Nexperia USA Inc.In Stock: 450774HC85D,653 Datasheet

MFR RecommendedRFQ

74HCT166D,653

Nexperia USA Inc.In Stock: 321274HCT166D,653 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CD74HCT166MT is determined by strict adherence to the following parameters:

Primary Substitution Criteria:

• Logic Type: Shift Register (8-bit, 1 element)
• Function: Parallel or Serial to Serial conversion
• Output Type: Push-Pull
• Package: 16-SOIC surface mount
• Voltage Supply Range: 4.5V ~ 5.5V
• Series Compatibility: 74HCT logic family

Substitute Parts Identified:

1. CD74HCT166M96 (Texas Instruments) — Parametric equivalent with identical electrical specifications and 16-SOIC packaging. Differs only in packaging format (Tape & Reel vs. Cut Tape) and product status (Active vs. Discontinued).

2. 74HCT166D,653 (Nexperia USA Inc.) — Functional equivalent within the 74HCT166 base product family. Maintains identical logic specifications, voltage supply range, and 16-SOIC package configuration. Product status is Active.

3. 74HC85D,653 (Nexperia USA Inc.) — This part is a magnitude comparator, not a shift register. It does not meet the primary substitution criteria and is not functionally equivalent to the CD74HCT166MT.

Parameter Comparison

Engineering Selection Recommendations

CD74HCT166M96 is the primary substitute for the CD74HCT166MT. Both parts are manufactured by Texas Instruments and share identical electrical and functional specifications. The only distinction is packaging format: CD74HCT166M96 is supplied in Tape & Reel format with Active product status, whereas the original part is Cut Tape format and Discontinued. This substitute provides direct functional replacement with improved availability.

74HCT166D,653 (Nexperia USA Inc.) is a secondary substitute option. It maintains full functional equivalence as a 74HCT166 base product family member with identical logic specifications and 16-SOIC packaging. The operating temperature range is narrower (-40°C ~ 125°C vs. -55°C ~ 125°C), which may be a consideration for applications requiring extended low-temperature operation. This part carries Active product status and ROHS3 compliance.

74HC85D,653 is not a suitable substitute. Despite sharing the same package format and logic family designation, it is a magnitude comparator with fundamentally different logic function and electrical characteristics. Selection of this part would result in circuit malfunction.

Frequently Asked Questions (FAQ)

Q: Can CD74HCT166M96 directly replace CD74HCT166MT in existing designs?

A: Yes. CD74HCT166M96 is a parametric equivalent with identical electrical specifications, logic function, voltage supply range, operating temperature range, and 16-SOIC package dimensions. The only difference is packaging format (Tape & Reel vs. Cut Tape), which does not affect circuit performance.

Q: What is the difference between CD74HCT166M96 and 74HCT166D,653?

A: Both are 8-bit parallel-in/serial-out shift registers with identical logic function and 16-SOIC packaging. CD74HCT166M96 is manufactured by Texas Instruments, while 74HCT166D,653 is manufactured by Nexperia USA Inc. The 74HCT166D,653 has a narrower operating temperature range (-40°C ~ 125°C vs. -55°C ~ 125°C). Both are ROHS3 compliant and carry Active product status.

Q: Why is 74HC85D,653 listed as a substitute but not recommended?

A: 74HC85D,653 is a magnitude comparator, not a shift register. It performs a different logic function and has different pin assignments and electrical behavior. It is not functionally equivalent to the CD74HCT166MT and would not operate correctly in circuits designed for shift register operation.

Q: Are all substitute parts in the same 16-SOIC package?

A: Yes. CD74HCT166M96 and 74HCT166D,653 are both housed in 16-SOIC (0.154", 3.90mm Width) surface mount packages, matching the original CD74HCT166MT package specification. This ensures mechanical and electrical compatibility on printed circuit boards.

Q: What compliance certifications apply to these substitute parts?

A: All substitute parts (CD74HCT166M96 and 74HCT166D,653) are ROHS3 compliant, REACH unaffected, and carry Moisture Sensitivity Level 1 (Unlimited). These certifications match the original CD74HCT166MT specifications.