AT28C64-12PI Equivalent & Substitute Parts

Part Overview

The AT28C64-12PI is a 64Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-DIP package with 120 ns access time. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and new designs. The AT28C64-12PI remains in stock inventory but is no longer in active production, making substitute parts critical for long-term component availability and supply chain continuity.

Substiute Parts

AT28C64-12PI

Microchip TechnologyIn Stock: 1421AT28C64-12PI Datasheet

Current PartRFQ

AT28C64B-15PU

Microchip TechnologyIn Stock: 3411AT28C64B-15PU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT28C64-12PI is determined by the following critical parameters:

• Memory Capacity & Organization: 64Kbit capacity with 8K x 8 organization is mandatory for functional equivalence
• Interface Type: Parallel interface is required for pin-compatible operation
• Package & Pinout: 28-DIP package with identical physical dimensions ensures mechanical and electrical compatibility
• Voltage Supply Range: 4.5V ~ 5.5V compatibility maintains circuit-level compatibility
• Operating Temperature Range: -40°C ~ 85°C ensures thermal compatibility with existing designs
• Access Time: Faster or equal access time (≤120 ns) ensures timing compatibility

The AT28C64B-15PU meets all substitution criteria. While it features a slower access time of 150 ns compared to the 120 ns of the AT28C64-12PI, this represents a backward-compatible specification change that does not compromise system functionality in applications where the original 120 ns timing was not a critical constraint.

Parameter Comparison

Engineering Selection Recommendations

The AT28C64B-15PU is the primary substitute for the AT28C64-12PI based on the following factors:

• Active Product Status: The AT28C64B-15PU is in active production, ensuring long-term availability and supply chain stability compared to the obsolete AT28C64-12PI
• RoHS3 Compliance: The substitute meets ROHS3 compliance requirements, whereas the original part is non-compliant, supporting modern manufacturing and environmental standards
• Functional Equivalence: Both parts share identical memory capacity, organization, interface type, package configuration, voltage supply range, and operating temperature range
• Timing Compatibility: The 150 ns access time of the substitute is slower than the 120 ns of the original part. This specification change is acceptable in applications where the original timing margin was not critical to system operation
• Pin Compatibility: Identical 28-DIP pinout ensures direct replacement without circuit board modifications

Selection of the AT28C64B-15PU is appropriate for new designs and legacy system support where component obsolescence requires substitution.

Frequently Asked Questions (FAQ)

Q: Can the AT28C64B-15PU directly replace the AT28C64-12PI without circuit modifications?

A: Yes. Both parts share identical pinout, package configuration, voltage supply range, and operating temperature range. Direct pin-for-pin substitution is possible on existing circuit boards.

Q: What is the impact of the 150 ns access time versus the original 120 ns specification?

A: The AT28C64B-15PU has a slower access time by 30 ns. This specification change is acceptable in applications where the original 120 ns timing was not a critical system constraint. Applications with strict timing requirements should evaluate whether the slower access time affects system performance.

Q: Why does the AT28C64B-15PU have a 10 ms write cycle time compared to 1 ms for the AT28C64-12PI?

A: The write cycle time difference reflects different internal programming algorithms between the two variants. Both parts meet the functional requirement of non-volatile memory storage. Applications should verify that the 10 ms write cycle time is compatible with system write operation timing.

Q: Is the AT28C64B-15PU suitable for new product designs?

A: Yes. The AT28C64B-15PU is in active production status and meets ROHS3 compliance requirements, making it suitable for new designs. The AT28C64-12PI, being obsolete and non-compliant, should not be used in new designs.

Q: Are there any packaging differences between the two parts?

A: Both parts use 28-DIP packaging with identical physical dimensions (0.600", 15.24mm). The AT28C64B-15PU is supplied in tube packaging, whereas the AT28C64-12PI packaging format is not specified in the provided data.