AT27C040-12PI Equivalent & Substitute Parts

Part Overview

The AT27C040-12PI is a 4Mbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 32-DIP package. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and component procurement. The AT27C040-12PI operates with a 120 ns access time and is designed for applications requiring non-volatile memory storage in through-hole configurations.

Substiute Parts

AT27C040-12PI

Microchip TechnologyIn Stock: 1132AT27C040-12PI Datasheet

Current PartRFQ

AT27C040-70PU

Microchip TechnologyIn Stock: 2849AT27C040-70PU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27C040-12PI is determined by strict equivalence across the following critical parameters:

• Memory capacity and organization (4Mbit, 512K x 8)
• Memory technology (EPROM - OTP)
• Parallel interface architecture
• Package form factor (32-DIP, 0.600")
• Voltage supply range (4.5V ~ 5.5V)
• Operating temperature range (-40°C ~ 85°C)

The AT27C040-70PU meets all these requirements. While it features a faster access time (70 ns versus 120 ns), this represents an improvement in performance and does not compromise compatibility. Both parts share the same base product number (AT27C040), confirming their functional equivalence within the AT27C040 family.

Parameter Comparison

Engineering Selection Recommendations

The AT27C040-70PU is the direct substitute for the AT27C040-12PI. Selection of the AT27C040-70PU is supported by the following factors:

• Both parts are manufactured by Microchip Technology and share identical core specifications for memory capacity, organization, interface, and package.
• The AT27C040-70PU is in active product status, ensuring ongoing availability and supply chain continuity.
• The AT27C040-70PU achieves ROHS3 compliance, whereas the AT27C040-12PI is non-compliant, making the substitute preferable for regulatory requirements.
• The faster access time (70 ns) of the substitute provides performance headroom without introducing compatibility issues.
• Pin-to-pin compatibility and identical package dimensions ensure direct replacement without PCB modifications.

Frequently Asked Questions (FAQ)

Q: Can the AT27C040-70PU directly replace the AT27C040-12PI without PCB modifications?

A: Yes. Both parts use the 32-DIP package with identical pin assignments and physical dimensions (0.600", 15.24mm). Direct socket replacement is possible.

Q: What is the difference between the 120 ns and 70 ns access times?

A: Access time specifies the maximum delay from address input to valid data output. The AT27C040-70PU's 70 ns access time is faster than the AT27C040-12PI's 120 ns. This faster performance is backward compatible and does not create timing conflicts in systems designed for the slower part.

Q: Are there any voltage or temperature differences between these parts?

A: No. Both parts operate within identical voltage supply ranges (4.5V ~ 5.5V) and temperature ranges (-40°C ~ 85°C). They are fully compatible in these respects.

Q: Why is the AT27C040-12PI listed as obsolete?

A: The AT27C040-12PI has been discontinued by Microchip Technology. The AT27C040-70PU remains in active production and is the recommended alternative for new designs and component replacement.

Q: Does the AT27C040-70PU meet modern compliance standards?

A: Yes. The AT27C040-70PU is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. The AT27C040-12PI does not meet these standards.

Q: Are both parts programmable through DiGi-Electronics?

A: The AT27C040-70PU is verified as programmable through DiGi-Electronics. The AT27C040-12PI's programmability status is not verified.