AT28HC256-12TU-T Equivalent & Substitute Parts

Part Overview

The AT28HC256-12TU-T is a 256Kbit parallel EEPROM memory IC manufactured by Microchip Technology, featuring 120 ns access time and 28-TSSOP surface mount packaging. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations. The substitute part maintains identical electrical specifications while offering different packaging configurations and active product status.

Substiute Parts

AT28HC256-12TU-T

Microchip TechnologyIn Stock: 1065AT28HC256-12TU-T Datasheet

Current PartRFQ

AT28HC256-12SU-T

Microchip TechnologyIn Stock: 725AT28HC256-12SU-T Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT28HC256-12TU-T is determined by strict equivalence across the following critical parameters:

• Memory capacity and organization (256Kbit, 32K x 8)
• Electrical interface specifications (parallel, 120 ns access time, 10ms write cycle)
• Supply voltage range (4.5V ~ 5.5V)
• Operating temperature range (-40°C ~ 85°C)
• Compliance certifications (ROHS3, MSL 3)

The AT28HC256-12SU-T qualifies as a direct substitute based on identical electrical and functional specifications. The primary difference is packaging configuration: the substitute uses 28-SOIC instead of 28-TSSOP, requiring PCB layout adjustment but maintaining full electrical compatibility.

Parameter Comparison

Engineering Selection Recommendations

The AT28HC256-12SU-T is the qualified substitute for the obsolete AT28HC256-12TU-T. Selection should be based on the following factors:

Product Status: The substitute part maintains active product status with Microchip Technology, ensuring continued availability and manufacturing support compared to the obsolete main part.

Compliance: Both parts maintain identical ROHS3 compliance and MSL 3 ratings, confirming equivalent environmental and regulatory qualification.

Packaging Consideration: The transition from 28-TSSOP to 28-SOIC packaging requires PCB footprint modification. The 28-SOIC package is narrower (7.50mm vs 11.80mm width) and uses different pin pitch geometry. Design teams must verify PCB layout compatibility before implementation.

Electrical Equivalence: Identical memory specifications, access timing, voltage requirements, and temperature ratings confirm full functional interchangeability at the circuit level.

Frequently Asked Questions (FAQ)

Q: Can AT28HC256-12SU-T directly replace AT28HC256-12TU-T without PCB modification?

A: No. While electrically equivalent, the packages differ: 28-TSSOP versus 28-SOIC. PCB footprint redesign is required. Pin assignments are identical, but physical dimensions and mounting geometry differ.

Q: Are the electrical specifications identical between these parts?

A: Yes. Both parts share identical memory capacity (256Kbit), access time (120 ns), write cycle time (10ms), supply voltage (4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C).

Q: What is the primary advantage of using the substitute part?

A: The AT28HC256-12SU-T maintains active product status, ensuring long-term availability and manufacturing support. The original AT28HC256-12TU-T is obsolete.

Q: Do both parts have the same compliance certifications?

A: Yes. Both are ROHS3 compliant with MSL 3 rating (168 hours), confirming equivalent environmental qualification.

Q: Is the 28-SOIC package smaller than 28-TSSOP?

A: Yes. The 28-SOIC package width is 7.50mm compared to 11.80mm for 28-TSSOP, resulting in a more compact footprint suitable for space-constrained applications.