AT27C040-70JC EPROM Memory IC Equivalent & Substitute Parts

Part Overview

The AT27C040-70JC is a 4Mbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 32-PLCC package with 70 ns access time. This component is classified as obsolete, making identification of compatible substitute parts essential for ongoing system support, legacy equipment maintenance, and design continuity. The part operates within a 4.5V to 5.5V supply voltage range and supports 512K x 8 memory organization with parallel interface architecture.

Substiute Parts

AT27C040-70JC

Microchip TechnologyIn Stock: 1524AT27C040-70JC Datasheet

Current PartRFQ

AT27C040-70JU

Microchip TechnologyIn Stock: 1812AT27C040-70JU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27C040-70JC is determined by strict equivalence across the following critical parameters:

• Memory capacity: 4Mbit
• Memory organization: 512K x 8
• Memory format and technology: EPROM - OTP
• Access time: 70 ns
• Supply voltage range: 4.5V ~ 5.5V
• Package type: 32-PLCC (13.97x11.43)
• Memory interface: Parallel
• Mounting type: Surface Mount

The AT27C040-70JU meets all these criteria and is identified as a direct substitute. The primary distinction between these parts lies in packaging format (Tube vs. standard packaging) and product status (Active vs. Obsolete), with the AT27C040-70JU offering extended operating temperature range and improved compliance status.

Parameter Comparison

Engineering Selection Recommendations

The AT27C040-70JU is a direct functional equivalent to the AT27C040-70JC with identical electrical and mechanical specifications. Selection between these parts should be based on the following factors:

Product Status: The AT27C040-70JU carries Active product status, ensuring continued manufacturer support and availability. The AT27C040-70JC is classified as Obsolete, limiting future procurement options.

Compliance Certifications: The AT27C040-70JU is ROHS3 compliant, meeting current environmental and regulatory requirements. The AT27C040-70JC is RoHS non-compliant, which may restrict use in applications subject to RoHS directives.

Operating Temperature Range: The AT27C040-70JU supports an extended operating temperature range of -40°C to 85°C, compared to the AT27C040-70JC range of 0°C to 70°C. This provides greater thermal flexibility for applications operating in extreme environments.

Packaging: The AT27C040-70JU is supplied in Tube packaging, which may differ from the original part's packaging format. Verify compatibility with existing assembly and handling procedures.

For new designs or system upgrades, the AT27C040-70JU is the preferred selection. For legacy system maintenance requiring exact original specifications, the AT27C040-70JC remains functionally equivalent where available.

Frequently Asked Questions (FAQ)

Q: Are the AT27C040-70JC and AT27C040-70JU pin-compatible?

A: Yes. Both parts use the 32-PLCC (13.97x11.43) package with identical pinout and J-Lead configuration. Direct socket substitution is possible without circuit board modifications.

Q: What is the difference between these two part numbers?

A: The primary differences are product status (Obsolete vs. Active), RoHS compliance (non-compliant vs. ROHS3 compliant), operating temperature range (0°C–70°C vs. -40°C–85°C), and packaging format (standard vs. Tube). All electrical and memory specifications are identical.

Q: Can the AT27C040-70JU replace the AT27C040-70JC in existing applications?

A: Yes, the AT27C040-70JU is a direct substitute. The extended operating temperature range and improved compliance status make it suitable for all applications originally designed for the AT27C040-70JC.

Q: What does EPROM - OTP technology mean?

A: OTP stands for One-Time Programmable. This EPROM variant can be programmed once by the user and cannot be erased or reprogrammed. It is distinct from standard EPROMs, which are erasable under ultraviolet light.

Q: Are there any thermal or environmental considerations when substituting these parts?

A: The AT27C040-70JU supports a wider operating temperature range (-40°C to 85°C) compared to the AT27C040-70JC (0°C to 70°C). If your application operates outside the 0°C to 70°C range, the AT27C040-70JU is required. Both parts maintain identical Moisture Sensitivity Level (MSL 2, 1 Year) and REACH compliance status.

Q: What does the "70" in the part number indicate?

A: The "70" specifies the access time of 70 nanoseconds. This is a critical timing parameter for memory read operations and must match the system's timing requirements.

Q: Is the packaging difference between these parts significant?

A: The AT27C040-70JU is supplied in Tube packaging, while the AT27C040-70JC may use different packaging. Verify that Tube packaging is compatible with your assembly equipment and handling procedures before procurement.