AT28C64-25PI Equivalent & Substitute Parts

Part Overview

The AT28C64-25PI is a 64Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-DIP package with 250 ns access time. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and new designs. The AT28C64-25PI operates within the 4.5V to 5.5V supply voltage range and supports through-hole mounting, making it suitable for legacy embedded systems and industrial applications requiring non-volatile parallel memory storage.

Substiute Parts

AT28C64-25PI

Microchip TechnologyIn Stock: 1412AT28C64-25PI Datasheet

Current PartRFQ

AT28C64B-15PU

Microchip TechnologyIn Stock: 3411AT28C64B-15PU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT28C64-25PI is determined by strict equivalence across the following critical parameters:

• Memory capacity and organization (64Kbit, 8K x 8 configuration)
• Parallel interface architecture
• Supply voltage compatibility (4.5V ~ 5.5V)
• Operating temperature range (-40°C ~ 85°C)
• Physical package form factor (28-DIP)
• Through-hole mounting compatibility

The AT28C64B-15PU qualifies as a direct substitute based on matching all mandatory electrical and mechanical parameters. While the AT28C64B-15PU exhibits improved access time (150 ns versus 250 ns) and write cycle time (10 ms versus 1 ms), these represent performance enhancements rather than incompatibilities. The substitute maintains identical memory capacity, organization, interface type, voltage range, temperature range, and package specifications.

Parameter Comparison

Engineering Selection Recommendations

The AT28C64B-15PU is the qualified substitute for the AT28C64-25PI based on product lifecycle and regulatory compliance considerations. The original AT28C64-25PI is classified as obsolete, creating supply chain risk for ongoing production and field support. The AT28C64B-15PU maintains active product status with verified availability, ensuring long-term sourcing capability.

From a regulatory perspective, the AT28C64B-15PU achieves ROHS3 compliance, whereas the AT28C64-25PI is non-compliant. This distinction is material for applications subject to RoHS directives or customer requirements mandating compliant component selection. Both parts maintain identical REACH and ECCN classifications.

The AT28C64B-15PU demonstrates superior electrical performance with 150 ns access time compared to the 250 ns specification of the AT28C64-25PI. This performance margin provides design headroom for timing-critical applications without introducing compatibility concerns.

Frequently Asked Questions (FAQ)

Q: Can the AT28C64B-15PU be used as a direct replacement for the AT28C64-25PI in existing designs?

A: Yes. Both parts share identical memory capacity (64Kbit), organization (8K x 8), parallel interface architecture, supply voltage range (4.5V ~ 5.5V), operating temperature range (-40°C ~ 85°C), and 28-DIP package form factor. Pin-for-pin compatibility is maintained, enabling direct substitution without circuit modification.

Q: What are the differences between these two parts?

A: The AT28C64B-15PU offers improved access time (150 ns versus 250 ns) and extended write cycle time (10 ms versus 1 ms). The AT28C64-25PI is obsolete while the AT28C64B-15PU maintains active product status. The AT28C64B-15PU is ROHS3 compliant; the AT28C64-25PI is not.

Q: Why is the AT28C64-25PI classified as obsolete?

A: Obsolescence reflects the manufacturer's discontinuation of this product line. The AT28C64B-15PU represents the current active equivalent within the Microchip AT28C64 family.

Q: Are there any package or mounting differences?

A: No. Both parts use identical 28-DIP (0.600", 15.24mm) packaging with through-hole mounting. PCB layout and socket compatibility remain unchanged.

Q: Does the improved access time of the AT28C64B-15PU affect system compatibility?

A: No. Faster access time represents a performance enhancement. Systems designed for 250 ns access time will operate correctly with the 150 ns substitute without timing violations.