AT28C256-15SC EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The AT28C256-15SC is a 256Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-SOIC surface mount package with 150 ns access time. This component is classified as obsolete, which necessitates identification of active equivalent parts for ongoing design support and procurement continuity. The part operates within a 4.5V to 5.5V supply voltage range and supports standard parallel memory interface protocols common in legacy embedded systems and industrial applications.

Substiute Parts

AT28C256-15SC

Microchip TechnologyIn Stock: 1289AT28C256-15SC Datasheet

Current PartRFQ

AT28C256-15SU

Microchip TechnologyIn Stock: 1290AT28C256-15SU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT28C256-15SC is determined by strict equivalence across the following critical parameters:

• Memory capacity and organization (256Kbit, 32K x 8 configuration)
• Parallel interface protocol and pin compatibility (28-SOIC package)
• Access time specification (150 ns)
• Write cycle time (10 ms)
• Supply voltage range (4.5V ~ 5.5V minimum overlap)
• Package mechanical dimensions and mounting type (28-SOIC surface mount)

The AT28C256-15SU qualifies as a direct substitute based on identical memory specifications, access timing, and package form factor. Differences in operating temperature range, product status, and compliance certifications do not affect functional substitutability for applications within the overlapping temperature specification (0°C ~ 70°C).

Parameter Comparison

Engineering Selection Recommendations

The AT28C256-15SU is the direct functional equivalent of the AT28C256-15SC. Selection between these parts should be based on the following criteria:

For new designs or redesigns: The AT28C256-15SU is the appropriate choice. It maintains active product status with Microchip Technology, carries ROHS3 compliance certification, and supports an extended operating temperature range (-40°C ~ 85°C) that exceeds the original part specification. The wider temperature range provides design margin for industrial and extended-temperature applications.

For legacy system maintenance: The AT28C256-15SU is compatible with existing designs specified for the AT28C256-15SC, provided the application operates within the overlapping temperature window (0°C ~ 70°C). The extended temperature capability of the substitute part does not introduce incompatibility.

Compliance considerations: The AT28C256-15SU meets ROHS3 compliance requirements, whereas the original part does not. For applications subject to RoHS directives or customer compliance mandates, the substitute part satisfies regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can the AT28C256-15SU directly replace the AT28C256-15SC in existing circuit designs?

A: Yes. Both parts share identical memory capacity (256Kbit), organization (32K x 8), access time (150 ns), write cycle time (10 ms), supply voltage range (4.5V ~ 5.5V), and 28-SOIC package form factor. Pin-for-pin compatibility is maintained.

Q: What is the significance of the different operating temperature ranges?

A: The AT28C256-15SC operates from 0°C to 70°C, while the AT28C256-15SU operates from -40°C to 85°C. For applications constrained to the 0°C to 70°C window, both parts are functionally equivalent. The substitute part's extended range provides additional design flexibility for temperature-critical applications without compromising compatibility.

Q: Does the RoHS3 compliance of the AT28C256-15SU affect compatibility?

A: No. RoHS3 compliance is a manufacturing and material standard that does not alter electrical or mechanical performance. The substitute part is fully compatible with designs specified for the original part.

Q: Are there packaging differences between these parts?

A: The AT28C256-15SU is supplied in tube packaging, while the original part packaging is not specified. Both use the same 28-SOIC surface mount package. Packaging format does not affect component functionality or circuit compatibility.

Q: Why is the original part classified as obsolete?

A: The AT28C256-15SC is no longer in active production by Microchip Technology. The AT28C256-15SU represents the current active equivalent, ensuring continued availability and support for this memory IC specification.