SN74AS158D Equivalent & Substitute Parts

Part Overview

The SN74AS158D is a 4 x 2:1 multiplexer logic integrated circuit manufactured by Texas Instruments in a 16-SOIC surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The SN74AS158D serves applications requiring multiplexing of four independent 2-to-1 data paths with TTL-compatible logic levels and single supply operation.

Substiute Parts

SN74AS158D

Texas InstrumentsIn Stock: 780SN74AS158D Datasheet

Current PartRFQ

SN74ALS157AD

Texas InstrumentsIn Stock: 2282SN74ALS157AD Datasheet

Parametric EquivalentRFQ

SN74ALS158D

Texas InstrumentsIn Stock: 1110SN74ALS158D Datasheet

Parametric EquivalentRFQ

SN74AS157D

Texas InstrumentsIn Stock: 1199SN74AS157D Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74AS158D are determined by matching the following critical parameters:

• Circuit configuration: 4 x 2:1 multiplexer topology
• Package type: 16-SOIC surface mount
• Voltage supply range: 4.5V ~ 5.5V single supply
• Output current specifications: 400µA high, 8mA low
• Operating temperature range: 0°C ~ 70°C
• Mounting type: Surface mount
• Compliance: ROHS3, MSL 1

The substitute parts identified—SN74ALS157AD, SN74ALS158D, and SN74AS157D—maintain identical electrical and mechanical specifications across all critical parameters. Substitution is valid based on functional equivalence within the allowed parameter set.

Parameter Comparison

Engineering Selection Recommendations

For designs currently using the SN74AS158D, the following selection criteria apply based on product status and compliance:

SN74ALS158D is the primary substitute. This part is active in production status and maintains full electrical and mechanical compatibility with the SN74AS158D. ROHS3 compliance and MSL 1 rating ensure equivalent environmental and regulatory qualification.

SN74AS157D is an alternative substitute within the same 74AS series. This part is active in production and provides identical parameter specifications. Selection between SN74ALS158D and SN74AS157D depends on design requirements for series-specific performance characteristics, though both meet the electrical and mechanical criteria for direct substitution.

SN74ALS157AD is available as a substitute with last-time-buy status. While electrically and mechanically equivalent, this part's product status indicates limited future availability and should be considered only when SN74ALS158D or SN74AS157D are unavailable.

Frequently Asked Questions (FAQ)

Q: Can SN74ALS158D be used as a direct replacement for SN74AS158D?

A: Yes. The SN74ALS158D meets all critical electrical and mechanical parameters: 4 x 2:1 multiplexer configuration, 16-SOIC package, 4.5V ~ 5.5V supply, 400µA/8mA output current, 0°C ~ 70°C operating range, and ROHS3 compliance. Direct substitution is valid.

Q: What is the difference between SN74AS157D and SN74ALS158D?

A: Both parts are functionally equivalent multiplexers with identical electrical specifications and 16-SOIC packaging. The primary difference is series designation: SN74AS157D belongs to the 74AS logic family, while SN74ALS158D belongs to the 74ALS family. Both are active in production.

Q: Is the 16-SOIC package identical across all substitute parts?

A: Yes. All substitute parts use the 16-SOIC (0.154", 3.90mm Width) surface mount package. PCB footprints and assembly processes are interchangeable.

Q: Why is SN74ALS157AD marked as last-time-buy?

A: Last-time-buy status indicates the manufacturer is discontinuing this part number. While currently available, procurement should prioritize SN74ALS158D or SN74AS157D for new designs to ensure long-term supply continuity.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed carry ROHS3 compliance certification and MSL 1 rating, meeting equivalent environmental and regulatory requirements.