AT27BV256-70RI Equivalent & Substitute Parts

Part Overview

The AT27BV256-70RI is a 256Kbit EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 28-SOIC surface mount package. This is a non-volatile, one-time programmable (OTP) memory device with parallel interface and 70 nanosecond access time. The product is currently obsolete, making identification of compatible substitute parts essential for system maintenance, repair, and legacy equipment support.

Substiute Parts

AT27BV256-70RI

Microchip TechnologyIn Stock: 1381AT27BV256-70RI Datasheet

Current PartRFQ

AT27BV256-70JU

Microchip TechnologyIn Stock: 1277AT27BV256-70JU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AT27BV256-70RI is determined by strict equivalence in the following core parameters:

• Memory Capacity & Organization: 256Kbit capacity with 32K x 8 organization
• Memory Technology: EPROM - OTP (One-Time Programmable)
• Interface Type: Parallel interface
• Access Time: 70 ns maximum
• Voltage Supply Ranges: Dual voltage operation (2.7V ~ 3.6V and 4.5V ~ 5.5V)
• Operating Temperature Range: -40°C ~ 85°C
• Manufacturer: Microchip Technology (AT27BV256 base product family)

The AT27BV256-70JU is a qualified substitute based on identical electrical specifications and memory characteristics. The primary difference is the package format (32-PLCC versus 28-SOIC), which requires PCB layout and socket compatibility verification.

Parameter Comparison

Engineering Selection Recommendations

The AT27BV256-70JU is the manufacturer-recommended substitute for the obsolete AT27BV256-70RI. Both devices share identical electrical and memory specifications, ensuring functional compatibility at the component level.

Product Status Consideration: The AT27BV256-70RI is obsolete with limited inventory availability. The AT27BV256-70JU maintains active product status, providing long-term supply chain reliability.

Compliance Status: The AT27BV256-70JU is ROHS3 compliant, whereas the AT27BV256-70RI is non-compliant. This distinction is relevant for applications subject to RoHS regulations.

Package Compatibility: The primary substitution constraint is the package format change from 28-SOIC to 32-PLCC. PCB socket design, pin pitch, and physical dimensions must be evaluated for mechanical fit and electrical routing compatibility.

Frequently Asked Questions (FAQ)

Q: Can the AT27BV256-70JU directly replace the AT27BV256-70RI without PCB modification?

A: Electrical substitution is valid; however, package format differs (28-SOIC versus 32-PLCC). Direct socket replacement requires compatible footprint design. Pin-to-pin functional mapping must be verified against device datasheets.

Q: What are the key electrical parameters that must match for substitution?

A: Memory capacity (256Kbit), organization (32K x 8), interface type (Parallel), access time (70 ns), voltage supply ranges (2.7V ~ 3.6V and 4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C) must be identical.

Q: Is the AT27BV256-70JU suitable for new designs?

A: Yes. The AT27BV256-70JU is active product status with ROHS3 compliance, making it appropriate for new applications requiring 256Kbit parallel EPROM functionality.

Q: What is the significance of the package designation change?

A: The 28-SOIC package uses a smaller footprint than the 32-PLCC package. Physical dimensions, pin count, and lead configuration differ, requiring PCB layout redesign for mechanical and electrical accommodation.

Q: Are there any supply chain advantages to using the AT27BV256-70JU?

A: Yes. The AT27BV256-70JU maintains active product status with documented inventory availability, whereas the AT27BV256-70RI is obsolete with declining stock levels.