SN74AS648NT Equivalent & Substitute Parts

Part Overview

The SN74AS648NT is an inverting transceiver IC manufactured by Texas Instruments, designed for 8-bit bidirectional data transfer with 3-state output capability. This device operates within a 4.5V to 5.5V supply voltage range and is housed in a 24-pin DIP package for through-hole mounting applications.

The SN74AS648NT is classified as obsolete. Locating equivalent substitute parts is necessary to support legacy system maintenance, design updates, and procurement continuity when original stock becomes unavailable.

Substiute Parts

SN74AS648NT

Texas InstrumentsIn Stock: 2337SN74AS648NT Datasheet

Current PartRFQ

SN74ALS648ADW

Texas InstrumentsIn Stock: 1025SN74ALS648ADW Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SN74AS648NT is determined by the following critical parameters:

• Logic Function: Transceiver, Inverting configuration with 1 element and 8 bits per element
• Output Characteristics: 3-state output capability
• Electrical Performance: Supply voltage range 4.5V ~ 5.5V and operating temperature 0°C ~ 70°C
• Output Current Ratings: Output high current of 15mA and output low current specifications
• Compliance: ROHS3 compliance and REACH unaffected status

The SN74ALS648ADW qualifies as a functional equivalent based on matching logic type, element configuration, bit width, output type, supply voltage range, and operating temperature specifications. The primary distinction is the packaging format: the substitute uses surface-mount 24-SOIC technology instead of through-hole 24-DIP mounting.

Parameter Comparison

Engineering Selection Recommendations

The SN74ALS648ADW is an active product with current manufacturing support from Texas Instruments, providing supply chain continuity for the obsolete SN74AS648NT. Both devices maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment.

The primary consideration for selection is mounting technology. The SN74AS648NT uses through-hole 24-DIP packaging, while the SN74ALS648ADW uses surface-mount 24-SOIC packaging. This difference requires PCB redesign if direct socket replacement is required. The output low current specification differs between the two devices (48mA versus 24mA), which may impact circuit performance in applications with specific current-sinking requirements.

Frequently Asked Questions (FAQ)

Q: Can the SN74ALS648ADW directly replace the SN74AS648NT in existing PCB designs?

A: Direct socket replacement is not possible due to different mounting technologies. The SN74AS648NT is a through-hole 24-DIP device, while the SN74ALS648ADW is a surface-mount 24-SOIC device. PCB redesign is required for substitution.

Q: Are the electrical specifications compatible between these two parts?

A: Both devices share the same logic type, element configuration, bit width, output type, supply voltage range, and operating temperature specifications. The output low current differs: SN74AS648NT provides 48mA while SN74ALS648ADW provides 24mA. Verify that your application can operate within the lower current specification.

Q: What is the significance of the product status difference?

A: The SN74AS648NT is obsolete and no longer manufactured. The SN74ALS648ADW is an active product with ongoing manufacturing support, ensuring long-term availability and supply chain reliability.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the SN74AS648NT and SN74ALS648ADW are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic components.

Q: What are the package dimension differences?

A: The SN74AS648NT uses a 24-DIP package measuring 0.300" (7.62mm), while the SN74ALS648ADW uses a 24-SOIC package measuring 0.295" (7.50mm) in width. These are physically incompatible form factors.