AT27BV256-70RC Equivalent & Substitute Parts

Part Overview

The AT27BV256-70RC 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 a 70 nanosecond access time and parallel interface, designed for applications requiring permanent data storage with fast read access.

The AT27BV256-70RC is classified as obsolete. Finding equivalent or substitute parts is necessary to support legacy system maintenance, board redesigns, or when original inventory becomes unavailable. Substitute parts must maintain functional equivalence in memory capacity, access time, electrical characteristics, and interface specifications.

Substiute Parts

AT27BV256-70RC

Microchip TechnologyIn Stock: 1072AT27BV256-70RC Datasheet

Current PartRFQ

AT27BV256-70JU

Microchip TechnologyIn Stock: 1277AT27BV256-70JU Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the AT27BV256-70RC is determined by the following critical parameters:

• Memory Capacity & Organization: Substitute parts must provide 256Kbit capacity in 32K x 8 organization to maintain data storage equivalence
• Access Time: 70 ns access time is the maximum allowable specification; substitutes must meet or exceed this performance
• Memory Interface: Parallel interface is mandatory for pin-level compatibility
• Voltage Supply Ranges: Substitute parts must support the same supply voltage ranges (2.7V ~ 3.6V and 4.5V ~ 5.5V) for circuit compatibility
• Mounting Type: Surface mount technology is required for PCB assembly compatibility
• Memory Technology: EPROM OTP technology ensures functional equivalence in non-volatile storage behavior

The AT27BV256-70JU meets all substitution criteria. While it uses a different package format (32-PLCC instead of 28-SOIC), it maintains electrical and functional equivalence across all critical parameters.

Parameter Comparison

Engineering Selection Recommendations

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

Functional Equivalence: Both parts share identical memory specifications (256Kbit, 32K x 8 organization, 70 ns access time, parallel interface) and electrical characteristics (supply voltage ranges, operating temperature range). The core memory functionality is fully equivalent.

Product Status: The AT27BV256-70JU maintains active product status with current manufacturing availability, whereas the AT27BV256-70RC is obsolete. Selection of the active part ensures long-term supply chain viability.

Compliance Status: The AT27BV256-70JU is ROHS3 compliant, meeting modern regulatory requirements. The original part is RoHS non-compliant. For new designs or systems requiring regulatory compliance, the substitute part is the appropriate choice.

Package Consideration: The substitute uses a 32-PLCC package instead of the original 28-SOIC package. This requires PCB redesign and socket/footprint modification. Pin mapping and signal routing must be verified against the respective datasheets to ensure correct implementation.

Frequently Asked Questions (FAQ)

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

A: No. The AT27BV256-70JU uses a 32-PLCC package while the original uses 28-SOIC. Although both are surface mount packages, the pin counts and physical layouts differ. PCB redesign is required, including new footprint layout and signal routing verification.

Q: Are the memory specifications identical between these parts?

A: Yes. Both parts provide 256Kbit capacity in 32K x 8 organization with 70 ns access time and parallel interface. Memory functionality is fully equivalent.

Q: What are the electrical supply requirements for the substitute part?

A: The AT27BV256-70JU supports the same dual voltage supply ranges as the original: 2.7V ~ 3.6V and 4.5V ~ 5.5V. Existing power supply designs require no modification.

Q: Does the operating temperature range differ between the parts?

A: Yes. The original AT27BV256-70RC operates from 0°C ~ 70°C, while the substitute AT27BV256-70JU operates from -40°C ~ 85°C. The substitute provides an extended temperature range, suitable for wider environmental conditions.

Q: What is the significance of the RoHS compliance difference?

A: The AT27BV256-70RC is RoHS non-compliant, while the AT27BV256-70JU is ROHS3 compliant. For applications subject to RoHS regulations or requiring compliance documentation, the substitute part is the appropriate selection.

Q: Are there any other AT27BV256 variants available?

A: Based on the provided data, the AT27BV256-70JU is the documented substitute. Other variants may exist in the AT27BV256 series, but only the AT27BV256-70JU is confirmed as an equivalent substitute meeting all critical parameters.