SN7438D NAND Gate IC Equivalent & Substitute Parts

Part Overview

The SN7438D is a 4-channel 2-input NAND gate IC with open collector output, manufactured by Texas Instruments in the 7400 logic series. This component is classified as Last Time Buy, indicating discontinued production with limited remaining inventory (1310 pcs). The SN7438D is packaged in 14-SOIC surface mount configuration and operates within the standard TTL voltage range of 4.75V to 5.25V.

Finding equivalent substitute parts is necessary due to the Last Time Buy status, which restricts future availability. Active production alternatives with identical electrical and mechanical specifications ensure design continuity and long-term supply chain reliability.

Substiute Parts

SN7438D

Texas InstrumentsIn Stock: 1349SN7438D Datasheet

Current PartRFQ

SN7438DR

Texas InstrumentsIn Stock: 48857SN7438DR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN7438D is determined by strict equivalence across the following critical parameters:

• Logic Function: NAND gate with 4 channels and 2 inputs per channel
• Output Configuration: Open collector topology
• Electrical Specifications: Supply voltage range (4.75V ~ 5.25V), quiescent current (8.5 mA max), output current (48mA max), input logic levels, and propagation delay (22ns @ 5V, 45pF)
• Package Format: 14-SOIC surface mount package with identical physical dimensions
• Compliance: ROHS3 compliance and MSL Level 1 rating

The SN7438DR qualifies as a direct substitute based on complete parameter alignment. The primary distinction is packaging format: SN7438D is supplied in Tube packaging with Last Time Buy status, while SN7438DR is supplied in Tape & Reel (TR) format with Active product status.

Parameter Comparison

Engineering Selection Recommendations

The SN7438DR is the recommended substitute for the SN7438D based on the following engineering criteria:

Product Status: The SN7438D carries Last Time Buy designation, signifying end-of-life production. The SN7438DR maintains Active status with continuous manufacturing support, ensuring long-term availability and supply chain stability.

Compliance Equivalence: Both parts maintain identical ROHS3 compliance and MSL Level 1 ratings, confirming regulatory and environmental compatibility across applications.

Electrical and Mechanical Parity: All functional parameters, electrical specifications, and package dimensions are identical. The 14-SOIC surface mount package, pin configuration, and electrical performance characteristics are fully equivalent.

Inventory Availability: The SN7438DR demonstrates significantly higher inventory levels (48775 pcs vs. 1310 pcs), reducing procurement risk and lead time variability.

Packaging Consideration: The transition from Tube to Tape & Reel (TR) packaging reflects standard manufacturing practices for active production. TR packaging is compatible with automated assembly processes and is the industry standard for high-volume production environments.

Frequently Asked Questions (FAQ)

Q: Can the SN7438DR be used as a direct replacement for the SN7438D in existing designs?

A: Yes. The SN7438DR is electrically and mechanically identical to the SN7438D. All electrical parameters, pin assignments, and package dimensions are equivalent. The only difference is the packaging format (Tape & Reel vs. Tube), which does not affect component functionality or performance.

Q: What is the significance of the Last Time Buy status on the SN7438D?

A: Last Time Buy indicates that Texas Instruments has discontinued production of the SN7438D. Existing inventory is limited to 1310 units. After depletion, this part number will no longer be available. The SN7438DR, with Active status, ensures continued availability for future production requirements.

Q: Are there any compatibility issues when transitioning from SN7438D to SN7438DR?

A: No compatibility issues exist. Both parts are from the same manufacturer (Texas Instruments), same logic series (7400), and share identical electrical specifications. The 14-SOIC package footprint is identical, allowing direct PCB compatibility without design modifications.

Q: How do the packaging formats differ between SN7438D and SN7438DR?

A: The SN7438D is supplied in Tube packaging, typically used for lower-volume or manual assembly applications. The SN7438DR is supplied in Tape & Reel (TR) format, optimized for automated pick-and-place assembly. TR packaging is the standard for production environments and offers improved handling efficiency.

Q: What are the key electrical parameters that define substitution eligibility for NAND gate ICs?

A: Substitution eligibility is determined by: logic function (4-channel 2-input NAND), output configuration (open collector), supply voltage range (4.75V ~ 5.25V), quiescent current (8.5 mA max), output current (48mA max), input logic levels (0.8V low, 2V high), propagation delay (22ns @ 5V, 45pF), and operating temperature range (0°C ~ 70°C). All these parameters must match exactly for functional equivalence.

Q: Is the SN7438DR suitable for new design implementations?

A: Yes. The SN7438DR is the recommended choice for new designs. Its Active product status ensures long-term availability, continuous manufacturing support, and stable supply chain performance. All electrical and mechanical specifications are identical to the SN7438D.