AT27C040-90JC EPROM Equivalent & Substitute Parts

Part Overview

The AT27C040-90JC is a 4Mbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 32-PLCC package with 90 ns access time. This component is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and new designs. The part operates within the 4.5V to 5.5V supply voltage range and supports 512K x 8 memory organization with parallel interface architecture.

Substiute Parts

AT27C040-90JC

Microchip TechnologyIn Stock: 1475AT27C040-90JC Datasheet

Current PartRFQ

AT27C040-90JU

Microchip TechnologyIn Stock: 1363AT27C040-90JU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the AT27C040-90JC is determined by strict equivalence across the following critical parameters:

• Memory capacity: 4Mbit
• Memory organization: 512K x 8
• Memory format and technology: EPROM - OTP
• Interface type: Parallel
• Access time: 90 ns
• Supply voltage range: 4.5V ~ 5.5V
• Package configuration: 32-PLCC (J-Lead)
• Mounting type: Surface Mount

The AT27C040-90JU meets all substitution criteria. Both parts share identical electrical specifications, memory architecture, and physical packaging. The primary distinction lies in product status and compliance certifications.

Parameter Comparison

Engineering Selection Recommendations

The AT27C040-90JU is the direct functional equivalent for the obsolete AT27C040-90JC. Selection between these parts should be based on the following criteria:

AT27C040-90JU is the preferred choice for new designs and ongoing production due to its active product status and ROHS3 compliance certification. This part accommodates extended operating temperature range (-40°C to 85°C) compared to the original specification (0°C to 70°C), providing broader environmental compatibility.

The AT27C040-90JC remains suitable for legacy system maintenance and repair applications where existing inventory is available and RoHS compliance is not a contractual requirement. However, long-term availability of this obsolete part is not assured.

Both parts share identical electrical performance, memory capacity, access timing, and physical packaging, ensuring direct pin-for-pin and functional compatibility in circuit implementations.

Frequently Asked Questions (FAQ)

Q: Can AT27C040-90JU directly replace AT27C040-90JC in existing designs?

A: Yes. Both parts are electrically and mechanically identical with matching pin configurations, memory specifications, and performance characteristics. The AT27C040-90JU operates across a wider temperature range (-40°C to 85°C versus 0°C to 70°C), which is compatible with applications designed for the original part.

Q: What is the difference between the -JC and -JU package designations?

A: The suffix indicates packaging format. The -JC variant uses standard packaging, while -JU uses tube packaging. Both employ identical 32-PLCC (J-Lead) physical configuration and surface mount technology.

Q: Why is AT27C040-90JC classified as obsolete?

A: Microchip Technology has discontinued active production and support for this part number. The AT27C040-90JU remains in active production and is the recommended alternative for new applications.

Q: Are there RoHS compliance implications when substituting these parts?

A: The AT27C040-90JC is RoHS non-compliant, while AT27C040-90JU is ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, the AT27C040-90JU is the appropriate selection.

Q: Do both parts support the same memory capacity and organization?

A: Yes. Both parts provide 4Mbit capacity with 512K x 8 organization, parallel interface, and 90 ns access time. Memory specifications are identical.

Q: What is the temperature operating range difference, and does it affect compatibility?

A: AT27C040-90JC operates 0°C to 70°C; AT27C040-90JU operates -40°C to 85°C. The wider range of the substitute part ensures compatibility with the original specification and extends usability to more demanding thermal environments.