SN74AS646NTG4 Equivalent & Substitute Parts

Part Overview

The SN74AS646NTG4 is a non-inverting transceiver IC manufactured by Texas Instruments, designed for 8-bit data transmission with 3-state output capability. This component 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 SN74AS646NTG4 carries an Obsolete product status. Locating equivalent substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or maintenance requirements for legacy systems utilizing this transceiver architecture.

Substiute Parts

SN74AS646NTG4

Texas InstrumentsIn Stock: 833SN74AS646NTG4 Datasheet

Current PartRFQ

SN74AS646DW

Texas InstrumentsIn Stock: 988SN74AS646DW Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74AS646NTG4 are identified based on functional and electrical equivalence within the 74AS646 product family. The following criteria determine valid substitution:

Functional Equivalence:

• Identical logic type: Transceiver, Non-Inverting
• Identical element and bit configuration: 1 Element, 8 Bits per Element
• Identical output type: 3-State

Electrical Equivalence:

• Matching output current specifications: 15mA (High), 48mA (Low)
• Matching supply voltage range: 4.5V ~ 5.5V
• Matching operating temperature range: 0°C ~ 70°C (TA)

Compliance Equivalence:

• RoHS3 Compliant status
• Moisture Sensitivity Level 1 (Unlimited)

The primary difference between the main part and its substitute lies in packaging and mounting technology. The SN74AS646NTG4 uses through-hole DIP packaging, while the substitute employs surface-mount SOIC packaging. Both share the same base product number (74AS646) and maintain identical electrical performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

The SN74AS646DW serves as the direct functional substitute for the SN74AS646NTG4. Both components maintain identical electrical specifications and compliance certifications, ensuring functional interchangeability at the circuit level.

The SN74AS646DW carries Active product status, providing superior long-term availability and supply chain stability compared to the Obsolete SN74AS646NTG4. Both parts maintain ROHS3 Compliant and REACH Unaffected certifications, supporting regulatory compliance requirements.

Selection between these parts depends on PCB assembly methodology. The SN74AS646NTG4 requires through-hole assembly techniques, while the SN74AS646DW requires surface-mount assembly capabilities. PCB design, manufacturing equipment, and assembly process constraints determine the appropriate choice for new designs or production transitions.

Frequently Asked Questions (FAQ)

Q: Can the SN74AS646DW directly replace the SN74AS646NTG4 in existing designs?

A: Electrical and functional replacement is direct. However, PCB layout and assembly process modifications are required. The SN74AS646NTG4 uses through-hole DIP packaging, while the SN74AS646DW uses surface-mount SOIC packaging. Footprint redesign and assembly process changes are necessary.

Q: Are the electrical specifications identical between these parts?

A: Yes. Both components share identical output current ratings (15mA High, 48mA Low), supply voltage range (4.5V ~ 5.5V), operating temperature range (0°C ~ 70°C), and logic functionality. Electrical performance is equivalent.

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

A: The SN74AS646NTG4 is Obsolete, indicating Texas Instruments no longer manufactures or supports this part. The SN74AS646DW is Active, meaning it remains in current production with ongoing manufacturer support and availability assurance.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the SN74AS646NTG4 and SN74AS646DW are ROHS3 Compliant, REACH Unaffected, and carry Moisture Sensitivity Level 1 (Unlimited). Regulatory compliance is equivalent.

Q: What are the package dimension differences?

A: The SN74AS646NTG4 uses 24-DIP packaging with 0.300" (7.62mm) pitch. The SN74AS646DW uses 24-SOIC packaging with 0.295" (7.50mm) width. These are distinct physical packages requiring different PCB footprints and assembly methods.