AT27C256R-45PI Equivalent & Substitute Parts

Part Overview

The AT27C256R-45PI is a 256Kbit EPROM (Erasable Programmable Read-Only Memory) IC manufactured by Microchip Technology, housed in a 28-DIP package with 45 ns access time. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and component procurement.

Substiute Parts

AT27C256R-45PI

Microchip TechnologyIn Stock: 1723AT27C256R-45PI Datasheet

Current PartRFQ

AT27C256R-45PU

Microchip TechnologyIn Stock: 1700AT27C256R-45PU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27C256R-45PI is determined by strict equivalence across the following parameters:

• Memory capacity: 256Kbit (32K x 8 organization)
• Memory interface: Parallel
• Access time: 45 ns
• Supply voltage range: 4.5V ~ 5.5V
• Operating temperature range: -40°C ~ 85°C
• Package type: 28-DIP through-hole
• Manufacturer: Microchip Technology (AT27C256 base product family)

The AT27C256R-45PU meets all these criteria and is identified as a direct substitute.

Parameter Comparison

Engineering Selection Recommendations

The AT27C256R-45PU is the direct functional equivalent of the AT27C256R-45PI. Both parts share identical electrical and mechanical specifications across all critical parameters. The primary distinction is product lifecycle status: the AT27C256R-45PI is obsolete, while the AT27C256R-45PU maintains active production status.

For new designs or component replenishment, the AT27C256R-45PU is the appropriate selection. This part also carries ROHS3 compliance, whereas the original part is non-compliant. Both parts are manufactured by Microchip Technology and maintain identical pinout, voltage requirements, and thermal operating ranges.

Frequently Asked Questions (FAQ)

Q: Can AT27C256R-45PU directly replace AT27C256R-45PI in existing designs?

A: Yes. Both parts are electrically and mechanically identical across all specified parameters. Pin configuration, voltage requirements, access time, and package dimensions are equivalent. Direct substitution is supported.

Q: What is the difference between the -45PI and -45PU suffix designations?

A: The suffix indicates packaging format. The PI designation denotes plastic DIP in tube packaging, while PU denotes plastic DIP in tube packaging as well. The electrical performance and pinout remain identical.

Q: Why is the AT27C256R-45PI listed as obsolete?

A: Product obsolescence reflects Microchip Technology's lifecycle management. The AT27C256R-45PU remains in active production and provides equivalent functionality for all applications.

Q: Are there RoHS compliance implications when substituting these parts?

A: The AT27C256R-45PI is RoHS non-compliant, while the AT27C256R-45PU is ROHS3 compliant. For applications subject to RoHS regulations, the AT27C256R-45PU is the required selection.

Q: Is the 28-DIP package footprint identical between both parts?

A: Yes. Both parts use the 28-DIP (0.600", 15.24mm) package with through-hole mounting. PCB layout and socket compatibility are identical.