AT27C1024-90JC Equivalent & Substitute Parts

Part Overview

The AT27C1024-90JC is a 1Mbit EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 44-PLCC surface mount package. This OTP (One-Time Programmable) memory device operates with a 90 ns access time and is designed for parallel interface applications requiring non-volatile storage. The part is currently classified as obsolete, making identification of compatible substitutes essential for legacy system maintenance and component sourcing.

Substiute Parts

AT27C1024-90JC

Microchip TechnologyIn Stock: 1137AT27C1024-90JC Datasheet

Current PartRFQ

AT27C1024-70JU

Microchip TechnologyIn Stock: 1467AT27C1024-70JU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27C1024-90JC is determined by strict equivalence across the following critical parameters:

• Memory capacity and organization (1Mbit, 64K x 16)
• Memory technology (EPROM - OTP, non-volatile)
• Interface type (Parallel)
• Package specification (44-PLCC with identical footprint)
• Supply voltage compatibility (4.5V ~ 5.5V)
• Physical mounting requirements (Surface Mount)

The AT27C1024-70JU qualifies as a direct substitute based on identical memory specifications, package geometry, and electrical interface requirements. The primary difference is improved access time performance (70 ns versus 90 ns), which represents a performance enhancement rather than a limitation for legacy applications.

Parameter Comparison

Engineering Selection Recommendations

The AT27C1024-70JU is the qualified substitute for the AT27C1024-90JC based on the following engineering criteria:

Functional Equivalence: Both devices share identical memory capacity (1Mbit), organization (64K x 16), technology (EPROM - OTP), and parallel interface architecture. Pin-to-pin compatibility and package footprint (44-PLCC) are identical, enabling direct board-level substitution.

Performance Enhancement: The AT27C1024-70JU provides faster access time (70 ns) compared to the original specification (90 ns). This represents improved performance characteristics that do not compromise legacy system compatibility.

Product Status and Availability: The AT27C1024-90JC is obsolete, while the AT27C1024-70JU maintains active product status with verified availability. This distinction is critical for ongoing component sourcing and supply chain continuity.

Compliance Considerations: The AT27C1024-70JU achieves ROHS3 compliance and extends the operating temperature range to -40°C ~ 85°C, providing broader environmental qualification compared to the original part's RoHS non-compliant status and 0°C ~ 70°C operating range.

Frequently Asked Questions (FAQ)

Q: Can the AT27C1024-70JU be used as a direct replacement for the AT27C1024-90JC?

A: Yes. Both devices are functionally equivalent EPROM components with identical memory capacity, organization, parallel interface, and 44-PLCC package specifications. The AT27C1024-70JU provides faster access time (70 ns versus 90 ns), which is compatible with legacy applications designed for the 90 ns part.

Q: Are there any pin compatibility concerns between these parts?

A: No. Both the AT27C1024-90JC and AT27C1024-70JU use the 44-PLCC package with identical pin assignments and footprint dimensions (16.6x16.6 mm). No PCB modifications are required for substitution.

Q: What is the significance of the access time difference?

A: Access time specifies the maximum delay from address input to valid data output. The AT27C1024-70JU's 70 ns access time is faster than the AT27C1024-90JC's 90 ns specification. Systems designed for 90 ns operation will function correctly with the faster 70 ns part without timing violations.

Q: Does the extended operating temperature range of the AT27C1024-70JU affect compatibility?

A: No. The AT27C1024-70JU's extended operating temperature range (-40°C ~ 85°C) is a superset of the original part's range (0°C ~ 70°C). Applications operating within the original temperature specification will function identically with the substitute part.

Q: What is the packaging difference between these parts?

A: The AT27C1024-90JC is supplied in standard packaging, while the AT27C1024-70JU is supplied in tube packaging. Both use the identical 44-PLCC component package. Tube packaging is a standard industry format for component handling and does not affect electrical or mechanical compatibility.

Q: Is RoHS compliance a factor in selecting the substitute?

A: The AT27C1024-70JU achieves ROHS3 compliance, while the AT27C1024-90JC is RoHS non-compliant. For applications subject to RoHS regulatory requirements, the AT27C1024-70JU provides compliant sourcing. For legacy systems without RoHS mandates, both parts are functionally equivalent.