AT28HC256E-90SC EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The AT28HC256E-90SC is a 256Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-SOIC surface mount package. This device operates with a 90 ns access time and supports 4.5V to 5.5V supply voltage across a 0°C to 70°C temperature range. The part is classified as obsolete, making identification of compatible substitutes essential for ongoing system support and component procurement.

Substiute Parts

AT28HC256E-90SC

Microchip TechnologyIn Stock: 1058AT28HC256E-90SC Datasheet

Current PartRFQ

AT28HC256E-90SU

Microchip TechnologyIn Stock: 1068AT28HC256E-90SU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the AT28HC256E-90SC is determined by the following critical parameters:

• Memory capacity (256Kbit) and organization (32K x 8)
• Parallel interface architecture
• Package type (28-SOIC with identical physical dimensions)
• Supply voltage compatibility (4.5V ~ 5.5V)
• Access time specification (90 ns or faster)
• Write cycle time (10 ms)

The AT28HC256E-90SU qualifies as a direct substitute based on matching all core electrical and mechanical specifications. This part maintains identical memory capacity, organization, interface type, package configuration, and timing parameters. The primary distinction is product status: AT28HC256E-90SU is active, whereas AT28HC256E-90SC is obsolete.

Parameter Comparison

Engineering Selection Recommendations

The AT28HC256E-90SU is the appropriate substitute for the obsolete AT28HC256E-90SC. Both parts share identical electrical specifications and package configurations, ensuring direct functional compatibility in existing circuit designs.

The AT28HC256E-90SU offers additional advantages: active product status ensures continued availability and manufacturing support, and ROHS3 compliance satisfies modern regulatory requirements. The extended operating temperature range (-40°C to 85°C) of the substitute provides broader environmental capability compared to the original part's 0°C to 70°C specification.

For applications requiring the original temperature range, the AT28HC256E-90SU remains fully compatible and suitable for deployment.

Frequently Asked Questions (FAQ)

Q: Can AT28HC256E-90SU directly replace AT28HC256E-90SC in existing designs?

A: Yes. Both parts are electrically and mechanically identical. The 28-SOIC package dimensions, pin configuration, memory capacity, access time, and supply voltage specifications are equivalent. No circuit modifications are required.

Q: What is the primary difference between these two parts?

A: The AT28HC256E-90SC is obsolete, while AT28HC256E-90SU is an active product. The substitute also features ROHS3 compliance and an extended operating temperature range (-40°C to 85°C versus 0°C to 70°C).

Q: Are there packaging differences between AT28HC256E-90SC and AT28HC256E-90SU?

A: No. Both parts use identical 28-SOIC surface mount packaging with 0.295" width (7.50mm). Pin count, spacing, and physical dimensions are the same.

Q: Does the extended temperature range of AT28HC256E-90SU affect compatibility?

A: No. The extended range (-40°C to 85°C) is a superset of the original specification (0°C to 70°C). The substitute operates correctly within the original temperature limits and beyond.

Q: Is RoHS compliance a functional requirement for substitution?

A: RoHS compliance is a regulatory and procurement consideration. The AT28HC256E-90SU's ROHS3 compliance satisfies modern environmental standards, whereas the original part does not. For new designs or systems with RoHS requirements, the substitute is the appropriate choice.