AT27C1024-90PC EPROM Equivalent & Substitute Parts

Part Overview

The AT27C1024-90PC is a 1Mbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 40-pin DIP package. This part operates with a 90 ns access time and is designed for applications requiring non-volatile memory storage with parallel interface architecture.

The AT27C1024-90PC is classified as obsolete. Locating equivalent or substitute components is necessary for system maintenance, legacy equipment repair, and design updates where continued sourcing of this specific variant is unavailable.

Substiute Parts

AT27C1024-90PC

Microchip TechnologyIn Stock: 2070AT27C1024-90PC Datasheet

Current PartRFQ

AT27C1024-70PU

Microchip TechnologyIn Stock: 5401AT27C1024-70PU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27C1024-90PC is determined by the following critical parameters:

• Memory Capacity & Organization: Substitute parts must maintain 1Mbit capacity with 64K x 16 organization to ensure address and data line compatibility
• Memory Interface: Parallel interface is mandatory for direct pin-level compatibility
• Package & Pinout: 40-DIP package with identical physical dimensions (0.600", 15.24mm) and through-hole mounting
• Voltage Supply Range: 4.5V ~ 5.5V compatibility ensures power distribution compatibility
• Access Time: The 90 ns specification represents maximum allowable access time; parts with equal or faster access times are functionally compatible

The AT27C1024-70PU meets all substitution criteria, offering improved performance characteristics while maintaining full electrical and mechanical compatibility.

Parameter Comparison

Engineering Selection Recommendations

The AT27C1024-70PU is a direct functional substitute for the AT27C1024-90PC based on the following engineering criteria:

Electrical Compatibility: Both parts operate within identical voltage supply ranges (4.5V ~ 5.5V) and maintain the same memory capacity, organization, and parallel interface architecture. The 70 ns access time of the substitute part is faster than the 90 ns specification of the main part, ensuring timing compatibility in all applications designed for the original component.

Mechanical Compatibility: Identical 40-DIP package dimensions and through-hole mounting enable direct socket replacement without PCB modification.

Product Status & Compliance: The AT27C1024-70PC is classified as active, ensuring continued availability. The substitute part carries ROHS3 compliance, whereas the main part is RoHS non-compliant. This distinction is relevant for applications subject to RoHS regulatory requirements.

Temperature Operating Range: The substitute part supports an extended operating temperature range (-40°C ~ 85°C) compared to the main part (0°C ~ 70°C), providing broader environmental compatibility.

Frequently Asked Questions (FAQ)

Q: Can the AT27C1024-70PU directly replace the AT27C1024-90PC in existing designs?

A: Yes. Both parts share identical memory capacity (1Mbit), organization (64K x 16), parallel interface, package type (40-DIP), and voltage supply range (4.5V ~ 5.5V). The 70 ns access time of the substitute is faster than the 90 ns specification, ensuring timing compatibility. No circuit modifications are required.

Q: What is the significance of the access time difference between 90 ns and 70 ns?

A: Access time defines the maximum delay from address input to valid data output. The 70 ns specification is a performance improvement; systems designed for 90 ns operation will function correctly with 70 ns components. No timing violations occur when substituting with faster parts.

Q: Are there packaging differences between these parts?

A: No. Both parts use 40-DIP packages with identical physical dimensions (0.600", 15.24mm) and through-hole mounting. They are mechanically interchangeable.

Q: What is the difference in operating temperature ranges?

A: The AT27C1024-90PC operates from 0°C to 70°C, while the AT27C1024-70PU operates from -40°C to 85°C. The substitute part supports a wider temperature envelope, making it suitable for applications requiring extended environmental operation.

Q: Does RoHS compliance affect substitution decisions?

A: RoHS compliance is a regulatory and procurement consideration. The AT27C1024-70PU is ROHS3 compliant, while the main part is non-compliant. For applications subject to RoHS requirements, the substitute part is the appropriate selection.

Q: Are both parts manufactured by the same company?

A: Yes. Both the AT27C1024-90PC and AT27C1024-70PU are manufactured by Microchip Technology, ensuring consistent design, quality standards, and reliability characteristics.