AT27C256R-70PC Equivalent & Substitute Parts

Part Overview

The AT27C256R-70PC is a 256Kbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 28-DIP package with 70 ns access time. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and new designs. The AT27C256R-70PC operates within the 4.5V to 5.5V supply voltage range and supports industrial temperature applications from 0°C to 70°C.

Substiute Parts

AT27C256R-70PC

Microchip TechnologyIn Stock: 1454AT27C256R-70PC Datasheet

Current PartRFQ

AT27C256R-70PU

Microchip TechnologyIn Stock: 6959AT27C256R-70PU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27C256R-70PC is determined by strict equivalence across the following critical parameters:

• Memory capacity: 256Kbit (32K x 8 organization)
• Memory interface: Parallel access
• Access time: 70 ns
• Supply voltage: 4.5V ~ 5.5V
• Package: 28-DIP form factor
• Mounting: Through Hole

The AT27C256R-70PU qualifies as a direct substitute based on identical electrical specifications and package configuration. Both parts share the same base product number (AT27C256), memory architecture, and interface characteristics. Differences in product status, operating temperature range, and compliance certifications do not affect functional interchangeability within the specified electrical parameters.

Parameter Comparison

Engineering Selection Recommendations

The AT27C256R-70PU is the direct functional equivalent for the obsolete AT27C256R-70PC. Selection between these parts should be based on the following criteria:

AT27C256R-70PU is the preferred choice for new designs and ongoing production. This part carries Active product status, ensuring continued availability and supply chain stability. The AT27C256R-70PU meets ROHS3 compliance requirements and supports an extended operating temperature range of -40°C to 85°C, providing greater flexibility for diverse application environments compared to the 0°C to 70°C range of the AT27C256R-70PC.

AT27C256R-70PC may be retained only in legacy systems where component-level compatibility with existing assemblies is mandatory and where the narrower operating temperature range (0°C to 70°C) is acceptable. The obsolete status of this part presents supply chain risk for future procurement.

Both parts maintain identical electrical performance and physical form factor, ensuring pin-for-pin compatibility and functional interchangeability within the specified electrical parameters.

Frequently Asked Questions (FAQ)

Q: Can the AT27C256R-70PU directly replace the AT27C256R-70PC in existing designs?

A: Yes. Both parts are electrically and mechanically equivalent. They share identical memory capacity (256Kbit), organization (32K x 8), access time (70 ns), supply voltage (4.5V ~ 5.5V), and 28-DIP package configuration. The AT27C256R-70PU operates across a wider temperature range (-40°C to 85°C versus 0°C to 70°C), making it suitable for applications requiring extended temperature performance.

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

A: The AT27C256R-70PC is classified as obsolete, while the AT27C256R-70PU maintains Active product status. The AT27C256R-70PU also provides ROHS3 compliance and extended operating temperature specifications. Functionally, both parts deliver identical memory performance and interface characteristics.

Q: Are there any package or mounting differences?

A: Both parts use the 28-DIP (0.600", 15.24mm) package with through-hole mounting. The AT27C256R-70PU is supplied in tube packaging, while the AT27C256R-70PC packaging specification is not detailed. This difference does not affect electrical or mechanical compatibility.

Q: Which part should be selected for new product development?

A: The AT27C256R-70PU is the appropriate choice for new designs. Its Active product status ensures supply availability, and ROHS3 compliance aligns with current regulatory requirements. The extended temperature range also provides design flexibility for applications across broader environmental conditions.

Q: Does the extended temperature range of the AT27C256R-70PU affect its electrical performance?

A: No. The extended operating temperature range (-40°C to 85°C) of the AT27C256R-70PU does not alter its core electrical specifications. Access time, supply voltage requirements, and memory organization remain identical to the AT27C256R-70PC across all operating conditions within their respective temperature ranges.