AT27BV256-90JC Equivalent & Substitute Parts

Part Overview

The AT27BV256-90JC is a 256Kbit EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 32-PLCC surface mount package. This part operates with a 90 ns access time and supports dual voltage supplies (2.7V–3.6V and 4.5V–5.5V). The device is classified as obsolete, making equivalent substitute parts necessary for ongoing system support and new design implementations where this memory capacity and interface are required.

Substiute Parts

AT27BV256-90JC

Microchip TechnologyIn Stock: 733AT27BV256-90JC Datasheet

Current PartRFQ

AT27BV256-70JU

Microchip TechnologyIn Stock: 1277AT27BV256-70JU Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the AT27BV256-90JC is determined by the following critical parameters:

• Memory Capacity & Organization: Substitute parts must maintain 256Kbit capacity with 32K x 8 organization to ensure data storage compatibility.
• Memory Interface: Parallel interface is mandatory for pin-level compatibility.
• Package & Pinout: 32-PLCC package with identical physical dimensions (13.97x11.43) ensures mechanical and electrical compatibility.
• Voltage Supply Compatibility: Substitute parts must support the same dual voltage ranges (2.7V–3.6V and 4.5V–5.5V) for circuit integration.
• Access Time: Faster or equal access times are acceptable; slower access times may impact system timing.

The AT27BV256-70JU qualifies as a direct substitute, offering improved performance characteristics while maintaining full electrical and mechanical compatibility.

Parameter Comparison

Engineering Selection Recommendations

The AT27BV256-70JU is the qualified substitute for the AT27BV256-90JC based on the following factors:

• Product Status: The substitute part is active and currently available, whereas the main part is obsolete. This ensures long-term supply chain viability.
• Performance Enhancement: The 70 ns access time of the substitute provides faster memory access compared to the 90 ns specification of the main part, improving system performance without compromising compatibility.
• Compliance: The AT27BV256-70JU meets ROHS3 compliance requirements, whereas the main part is non-compliant. This is significant for applications subject to environmental and regulatory standards.
• Temperature Range: The substitute supports an extended operating temperature range (-40°C to 85°C) compared to the main part (0°C to 70°C), providing greater flexibility for diverse operating environments.
• Electrical Compatibility: Both parts maintain identical voltage supply specifications and parallel interface architecture, ensuring direct functional substitution without circuit redesign.

Frequently Asked Questions (FAQ)

Q: Can the AT27BV256-70JU be used as a direct replacement for the AT27BV256-90JC?

A: Yes. Both parts share identical memory capacity (256Kbit), organization (32K x 8), parallel interface, package type (32-PLCC), and voltage supply specifications (2.7V–3.6V, 4.5V–5.5V). The substitute offers faster access time (70 ns vs. 90 ns) and extended temperature range, making it functionally compatible without circuit modification.

Q: What is the primary difference between these two parts?

A: The main differences are access time (90 ns vs. 70 ns), operating temperature range (0°C–70°C vs. -40°C–85°C), product status (obsolete vs. active), and RoHS compliance (non-compliant vs. ROHS3 compliant). The substitute provides superior performance and regulatory compliance.

Q: Are the packages physically identical?

A: Yes. Both parts use the 32-PLCC package with identical dimensions (13.97x11.43 mm), ensuring mechanical compatibility on PCBs designed for the AT27BV256-90JC.

Q: Does the faster access time of the substitute affect system compatibility?

A: No. Faster access times are backward compatible. Systems designed for 90 ns access will operate correctly with the 70 ns substitute without timing violations.

Q: Is the extended temperature range of the substitute a concern for standard applications?

A: No. The extended range (-40°C to 85°C) of the substitute encompasses the original operating range (0°C to 70°C), ensuring compatibility across all intended operating conditions of the main part.

Q: What is the significance of RoHS3 compliance on the substitute?

A: ROHS3 compliance indicates adherence to current environmental and hazardous substance restrictions. This is essential for applications subject to regulatory requirements in electronics manufacturing and end-of-life disposal.