AT27BV256-12RI Equivalent & Substitute Parts

Part Overview

The AT27BV256-12RI is a 256Kbit EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 28-SOIC surface mount package. This is an OTP (One-Time Programmable) non-volatile memory device with a 120 ns access time, designed for parallel interface applications requiring dual voltage supply operation (2.7V–3.6V and 4.5V–5.5V).

The AT27BV256-12RI is classified as obsolete. Finding equivalent or substitute parts is necessary due to limited availability and the discontinuation of this specific variant. Substitute parts maintain core memory functionality while offering improved product status, compliance certifications, or alternative packaging options.

Substiute Parts

AT27BV256-12RI

Microchip TechnologyIn Stock: 911AT27BV256-12RI Datasheet

Current PartRFQ

AT27BV256-70JU

Microchip TechnologyIn Stock: 1277AT27BV256-70JU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the AT27BV256-12RI is determined by the following critical parameters:

• Memory Capacity & Organization: Must be 256Kbit with 32K x 8 organization
• Memory Type & Technology: Must be EPROM with OTP technology and non-volatile operation
• Memory Interface: Must support parallel interface
• Voltage Supply Compatibility: Must support both 2.7V–3.6V and 4.5V–5.5V supply ranges
• Operating Temperature Range: Must maintain -40°C to 85°C specification
• Manufacturer: Microchip Technology (base product AT27BV256 series)

The AT27BV256-70JU qualifies as a substitute because it maintains identical memory capacity, organization, technology, interface, voltage supply, and temperature specifications. The primary differences are access time (70 ns versus 120 ns) and package format (32-PLCC versus 28-SOIC), both of which represent functional improvements or alternative form factors rather than incompatibilities.

Parameter Comparison

Engineering Selection Recommendations

The AT27BV256-70JU is the qualified substitute for the AT27BV256-12RI based on the following engineering criteria:

Functional Equivalence: Both devices share identical memory capacity (256Kbit), organization (32K x 8), technology (EPROM-OTP), interface (parallel), voltage supply ranges (2.7V–3.6V and 4.5V–5.5V), and operating temperature specifications (-40°C to 85°C). These parameters define functional compatibility for memory applications.

Product Status: The AT27BV256-70JU carries Active product status, ensuring ongoing availability and support, whereas the AT27BV256-12RI is Obsolete. This status difference is significant for procurement and long-term supply chain planning.

Compliance Certification: The AT27BV256-70JU is ROHS3 Compliant, meeting current environmental and regulatory standards. The AT27BV256-12RI is RoHS non-compliant, which may present restrictions in certain applications or markets.

Performance Characteristic: The AT27BV256-70JU offers a faster access time (70 ns) compared to the main part (120 ns). This represents a performance improvement and does not introduce compatibility issues.

Package Consideration: The AT27BV256-70JU uses a 32-PLCC package versus the 28-SOIC package of the main part. PCB layout and socket compatibility must be evaluated during design integration.

Frequently Asked Questions (FAQ)

Q: Can the AT27BV256-70JU directly replace the AT27BV256-12RI in existing designs?

A: Functional replacement is possible because both devices maintain identical memory capacity, organization, technology, interface, and voltage supply specifications. However, the package difference (32-PLCC versus 28-SOIC) requires PCB layout modification and socket compatibility assessment. Pin-to-pin correspondence must be verified against the respective datasheets.

Q: What is the significance of the access time difference (70 ns versus 120 ns)?

A: The AT27BV256-70JU has a faster access time, meaning data retrieval occurs more quickly. This is a performance improvement and does not create compatibility issues. Systems designed for 120 ns operation will function correctly with 70 ns devices.

Q: Does the ROHS3 compliance of the AT27BV256-70JU affect compatibility?

A: ROHS3 compliance indicates adherence to environmental and hazardous substance restrictions. This does not affect electrical or functional compatibility. It may be required for certain applications or markets, making the substitute preferable from a regulatory standpoint.

Q: Are there pin-count differences between the two packages?

A: Yes. The AT27BV256-12RI uses a 28-SOIC package (28 pins), while the AT27BV256-70JU uses a 32-PLCC package (32 pins). Pin assignments and functionality must be cross-referenced with datasheets to ensure correct circuit integration.

Q: What voltage supply ranges do both devices support?

A: Both the AT27BV256-12RI and AT27BV256-70JU support dual voltage operation: 2.7V–3.6V and 4.5V–5.5V. This dual-voltage capability is maintained across both parts, ensuring compatibility in applications using either supply range.

Q: Is the AT27BV256-70JU the only substitute available?

A: Based on the provided data, the AT27BV256-70JU is the documented substitute meeting all critical substitution parameters for the AT27BV256-12RI.