AT28HC256F-90SC EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The AT28HC256F-90SC is a 256Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-SOIC surface mount package with 90 ns access time. This component is classified as obsolete, making substitute parts necessary for new designs and ongoing production support. The part operates within a 4.5V to 5.5V supply voltage range and supports 32K x 8 memory organization with a 3ms write cycle time.

Substiute Parts

AT28HC256F-90SC

Microchip TechnologyIn Stock: 1054AT28HC256F-90SC Datasheet

Current PartRFQ

AT28HC256F-90SU

Microchip TechnologyIn Stock: 939AT28HC256F-90SU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the AT28HC256F-90SC is determined by strict equivalence across the following critical parameters:

• Memory capacity: 256Kbit
• Memory organization: 32K x 8
• Interface type: Parallel
• Access time: 90 ns
• Package: 28-SOIC surface mount
• Supply voltage: 4.5V ~ 5.5V compatible
• Write cycle time: 3ms

The AT28HC256F-90SU qualifies as a direct substitute based on identical electrical specifications and package configuration. The primary distinction lies in product status and operating temperature range, which affects suitability for different application environments.

Parameter Comparison

Engineering Selection Recommendations

The AT28HC256F-90SU is the qualified substitute for AT28HC256F-90SC based on the following factors:

Product Status: The AT28HC256F-90SU carries Active product status, ensuring continued manufacturer support and availability, whereas the AT28HC256F-90SC is obsolete.

Compliance: The AT28HC256F-90SU meets ROHS3 compliance requirements, compared to the non-compliant status of the main part. This is significant for applications subject to environmental regulations.

Operating Temperature Range: The AT28HC256F-90SU supports -40°C to 85°C operation, extending the lower and upper temperature limits beyond the AT28HC256F-90SC specification of 0°C to 70°C. This broader range accommodates industrial and extended-temperature applications.

Electrical Equivalence: Both parts maintain identical memory capacity, organization, access time, write cycle time, and supply voltage specifications, ensuring functional interchangeability at the circuit level.

Packaging: The AT28HC256F-90SU is supplied in Tube packaging, facilitating automated assembly processes.

Frequently Asked Questions (FAQ)

Q: Can AT28HC256F-90SU replace AT28HC256F-90SC in existing designs?

A: Yes. Both parts share identical electrical specifications including memory size, organization, access time, write cycle time, and supply voltage. The 28-SOIC package footprint is identical, enabling direct PCB substitution.

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

A: The AT28HC256F-90SC operates from 0°C to 70°C, while the AT28HC256F-90SU operates from -40°C to 85°C. The substitute part supports a wider temperature range, making it suitable for industrial, automotive, and extended-temperature environments where the main part may not be rated.

Q: Why is product status important for component selection?

A: The AT28HC256F-90SC is obsolete, indicating discontinued manufacturing and limited availability. The AT28HC256F-90SU is Active, ensuring ongoing production, manufacturer support, and reliable supply chain access for current and future production runs.

Q: Does RoHS compliance affect functional performance?

A: RoHS compliance does not alter electrical function. The AT28HC256F-90SU's ROHS3 compliance is a manufacturing and environmental requirement relevant for applications subject to regulatory restrictions on hazardous substances.

Q: Are there any package or pinout differences?

A: No. Both parts use the 28-SOIC package with identical 0.295" width and 7.50mm dimensions. Pinout and footprint are equivalent, supporting direct board-level substitution.

Q: What inventory considerations apply to these parts?

A: The AT28HC256F-90SC has 1041 pieces in stock as new original inventory. The AT28HC256F-90SU has 904 pieces available. Inventory levels may vary; consult current availability for production planning.