AT27BV256-12TC Equivalent & Substitute Parts

Part Overview

The AT27BV256-12TC is a 256Kbit parallel EPROM (Erasable Programmable Read-Only Memory) manufactured by Microchip Technology in a 28-TSOP surface mount package. This device is classified as obsolete, indicating it has been discontinued and is no longer in active production. Finding equivalent or substitute parts is necessary due to the obsolete status and potential supply constraints for new designs or legacy system maintenance.

Substiute Parts

AT27BV256-12TC

Microchip TechnologyIn Stock: 920AT27BV256-12TC Datasheet

Current PartRFQ

AT27BV256-70JU

Microchip TechnologyIn Stock: 1277AT27BV256-70JU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the AT27BV256-12TC is based on the following critical parameters:

• Memory Capacity & Organization: Substitute parts must maintain 256Kbit capacity with 32K x 8 organization to ensure functional compatibility with existing circuit designs and firmware.
• Memory Technology: Both main and substitute parts must use EPROM - OTP (One-Time Programmable) technology to preserve the non-volatile storage characteristics.
• Memory Interface: Parallel interface is mandatory for pin-level compatibility with host systems.
• Voltage Supply Compatibility: Substitute parts must support the same supply voltage ranges (2.7V ~ 3.6V and 4.5V ~ 5.5V) to function in existing power delivery architectures.
• Base Product Number: All substitutes share the AT27BV256 base product number, confirming they are variants of the same core device family.

The AT27BV256-70JU qualifies as a substitute based on these parameters. While it differs in access time (70 ns vs. 120 ns), operating temperature range, package type, and compliance status, these differences represent improvements or variations that do not prevent functional substitution in applications designed for the AT27BV256 family.

Parameter Comparison

Engineering Selection Recommendations

The AT27BV256-70JU is the manufacturer-recommended substitute for the AT27BV256-12TC. Selection should be based on the following factors:

Product Status: The AT27BV256-12TC is obsolete, while the AT27BV256-70JU is active. For new designs or long-term supply assurance, the active substitute is the appropriate choice.

Compliance & Certifications: The AT27BV256-70JU is ROHS3 compliant with improved moisture sensitivity rating (MSL 2 vs. MSL 3), making it suitable for applications with stricter environmental and regulatory requirements.

Performance Characteristics: The AT27BV256-70JU offers faster access time (70 ns vs. 120 ns) and extended operating temperature range (-40°C ~ 85°C vs. 0°C ~ 70°C), providing greater operational flexibility.

Package Consideration: The substitute uses a 32-LCC (J-Lead) package instead of the 28-TSSOP package. PCB layout and socket compatibility must be evaluated for physical integration.

Frequently Asked Questions (FAQ)

Q: Can the AT27BV256-70JU directly replace the AT27BV256-12TC without circuit modifications?

A: Functional substitution is possible because both devices share identical memory capacity (256Kbit), organization (32K x 8), interface type (Parallel), and voltage supply ranges. However, the package difference (28-TSSOP vs. 32-LCC) requires PCB redesign or adapter solutions for physical integration.

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

A: The AT27BV256-70JU has faster access time, meaning data retrieval occurs more quickly. This is a performance improvement that does not prevent substitution; systems designed for 120 ns operation will function correctly with 70 ns devices.

Q: Why is the operating temperature range different?

A: The AT27BV256-70JU supports a wider temperature range (-40°C ~ 85°C) compared to the AT27BV256-12TC (0°C ~ 70°C). This expanded range provides greater flexibility for applications in extreme environments but does not affect substitution in systems operating within the original temperature specification.

Q: What does RoHS3 compliance mean for the substitute part?

A: RoHS3 compliance indicates the AT27BV256-70JU meets Restriction of Hazardous Substances regulations, restricting the use of specific hazardous materials. The original AT27BV256-12TC is non-compliant. For applications requiring regulatory compliance, the substitute is the appropriate choice.

Q: How does the package change affect substitution?

A: The AT27BV256-12TC uses a 28-TSSOP package while the AT27BV256-70JU uses a 32-LCC package. These are physically different packages with different pin counts and layouts. Direct socket substitution is not possible; PCB redesign or mechanical adapters are required.

Q: Are there any inventory or supply considerations?

A: The AT27BV256-12TC is obsolete with limited remaining stock. The AT27BV256-70JU is active production with established supply channels, making it the preferred choice for ongoing or new applications requiring long-term availability.