AT27C1024-55JC Equivalent & Substitute Parts

Part Overview

The AT27C1024-55JC is a 1Mbit EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology, configured as 64K x 16 with parallel interface in a 44-PLCC surface mount package. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and component procurement.

Substiute Parts

AT27C1024-55JC

Microchip TechnologyIn Stock: 1618AT27C1024-55JC Datasheet

Current PartRFQ

AT27C1024-45JU

Microchip TechnologyIn Stock: 1851AT27C1024-45JU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27C1024-55JC is determined by strict equivalence across the following parameters:

• Memory capacity and organization (1Mbit, 64K x 16)
• Parallel interface architecture
• Package form factor (44-PLCC surface mount)
• Supply voltage range (4.5V ~ 5.5V)
• Pin-to-pin compatibility

The AT27C1024-45JU qualifies as a direct substitute based on identical memory specifications, organization, interface type, and package configuration. Differences in access time (45 ns vs. 55 ns) and operating temperature range represent performance enhancements rather than compatibility constraints, as faster access times and extended temperature ranges are backward-compatible with applications designed for the original part.

Parameter Comparison

Engineering Selection Recommendations

The AT27C1024-45JU is the direct functional equivalent for AT27C1024-55JC replacement. Selection of the substitute part is supported by:

• Active product status, ensuring long-term availability and supply chain continuity
• ROHS3 compliance, meeting current environmental and regulatory requirements
• Identical memory architecture, capacity, and parallel interface specifications
• Pin-to-pin compatibility within the 44-PLCC package footprint
• Improved access time (45 ns) and extended operating temperature range (-40°C ~ 85°C), providing performance margin over the original specification

The AT27C1024-45JU accommodates applications originally designed for the AT27C1024-55JC without circuit modification or redesign.

Frequently Asked Questions (FAQ)

Q: Can the AT27C1024-45JU be used as a direct replacement for the AT27C1024-55JC?

A: Yes. Both parts share identical memory capacity (1Mbit), organization (64K x 16), parallel interface, and 44-PLCC package configuration. Pin assignments and electrical interface are equivalent.

Q: What is the significance of the access time difference (55 ns vs. 45 ns)?

A: The AT27C1024-45JU has faster access time, which is a performance enhancement. Systems designed for 55 ns access time operate correctly with 45 ns parts, as the faster device meets or exceeds timing requirements.

Q: Does the extended operating temperature range of the AT27C1024-45JU affect compatibility?

A: No. The extended range (-40°C ~ 85°C vs. 0°C ~ 70°C) is a superset of the original specification. Applications within the original temperature window function identically.

Q: What is the impact of RoHS compliance differences?

A: The AT27C1024-45JU is ROHS3 compliant, while the AT27C1024-55JC is non-compliant. For new designs and systems subject to environmental regulations, the compliant substitute is required. Existing systems using the non-compliant part may continue operation without modification.

Q: Are there packaging or handling differences between these parts?

A: The AT27C1024-45JU is supplied in tube packaging with Moisture Sensitivity Level 3 (168 hours), compared to the original part's MSL 2 (1 year). Standard ESD and moisture control procedures apply during storage and handling.

Q: Is the AT27C1024-45JU programmable through DiGi-Electronics?

A: Yes. The AT27C1024-45JU is verified as programmable through DiGi-Electronics, whereas the original part's programmability status is not verified.