AT28C256-15SA EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The AT28C256-15SA is a 256Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-SOIC surface mount package. This device provides non-volatile memory storage with 150 ns access time and operates across the industrial temperature range of -40°C to 125°C. The part is currently classified as obsolete, making identification of compatible substitutes essential for ongoing system support and component procurement.

Substiute Parts

AT28C256-15SA

Microchip TechnologyIn Stock: 864AT28C256-15SA Datasheet

Current PartRFQ

AT28C256-15SU

Microchip TechnologyIn Stock: 1290AT28C256-15SU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

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

• Memory capacity: 256Kbit (32K x 8 organization)
• Interface type: Parallel
• Access time: 150 ns
• Write cycle time: 10ms
• Supply voltage range: 4.5V ~ 5.5V
• Package: 28-SOIC surface mount

The AT28C256-15SU meets all electrical and mechanical requirements for direct substitution. Both parts share identical memory specifications, timing characteristics, voltage requirements, and physical packaging. The primary distinction lies in product status and compliance certifications rather than functional parameters.

Parameter Comparison

Engineering Selection Recommendations

The AT28C256-15SU is the direct functional equivalent of the AT28C256-15SA. Both parts deliver identical electrical performance and occupy the same physical footprint. Selection between these parts depends on application requirements:

The AT28C256-15SA supports the extended industrial temperature range (-40°C to 125°C) and remains suitable for legacy systems already deployed with this component. However, the part is obsolete and subject to inventory depletion.

The AT28C256-15SU is the active production alternative, offering ROHS3 compliance and verified programmability status. The operating temperature range is limited to -40°C to 85°C. This substitution is appropriate for new designs and ongoing production where the reduced temperature ceiling does not conflict with system specifications.

Frequently Asked Questions (FAQ)

Q: Can AT28C256-15SU directly replace AT28C256-15SA in existing designs?

A: Yes, provided the application does not require operation above 85°C. All electrical parameters, memory capacity, access time, and physical packaging are identical. The primary difference is the maximum operating temperature specification.

Q: What is the significance of the temperature range difference?

A: The AT28C256-15SA operates to 125°C while the AT28C256-15SU operates to 85°C. Systems designed for extended temperature operation must verify that 85°C satisfies their thermal requirements before substitution.

Q: Are there packaging differences between these parts?

A: No. Both parts use 28-SOIC surface mount packaging with identical dimensions (0.295", 7.50mm width). PCB layout and reflow profiles remain unchanged.

Q: What does RoHS3 compliance mean for the AT28C256-15SU?

A: ROHS3 compliance indicates the part meets current Restriction of Hazardous Substances directives. The AT28C256-15SA is RoHS non-compliant, which may affect procurement for regulated applications or new product certifications.

Q: Are the memory specifications identical?

A: Yes. Both parts provide 256Kbit capacity organized as 32K x 8, with 150 ns access time, 10ms write cycle time, and parallel interface. Memory performance is equivalent.