AT28HC64B-90JC EEPROM Equivalent & Substitute Parts

Part Overview

The AT28HC64B-90JC is a 64Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 32-PLCC package with 90 ns access time. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations. The part operates within a 4.5V to 5.5V supply range and supports 8K x 8 memory organization with 10ms write cycle time.

Key Parameters

Parameter	Value
Memory Size	64Kbit
Memory Organization	8K x 8
Memory Interface	Parallel
Access Time	90 ns
Write Cycle Time	10ms
Voltage Supply	4.5V ~ 5.5V
Package Type	32-PLCC (13.97x11.43)
Mounting Type	Surface Mount
Operating Temperature	0°C ~ 70°C

Substitute Part Grouping Explanation

Substitution for the AT28HC64B-90JC is determined by strict alignment of core electrical and mechanical parameters: memory capacity (64Kbit), organization (8K x 8), interface type (parallel), package format (32-PLCC), and supply voltage (4.5V ~ 5.5V). Access time and write cycle time are secondary selection criteria that determine performance compatibility within the same functional class.

The substitute parts identified maintain identical memory specifications and package dimensions, ensuring mechanical and electrical interchangeability. Differences in access time (90 ns vs. 120 ns) and write cycle time (10ms vs. 5ms) represent performance variations that do not prevent substitution in most applications, provided system timing requirements are met.

Parameter Comparison

Parameter	AT28HC64B-90JC	AT28HC64B-90JU	X28HC64JIZ-12	X28HC64JIZ-12T1
Manufacturer	Microchip Technology	Microchip Technology	Renesas Electronics	Renesas Electronics
Memory Size	64Kbit	64Kbit	64Kbit	64Kbit
Memory Organization	8K x 8	8K x 8	8K x 8	8K x 8
Access Time	90 ns	90 ns	120 ns	120 ns
Write Cycle Time	10ms	10ms	5ms	5ms
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Package Type	32-PLCC	32-PLCC	32-PLCC	32-PLCC
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Product Status	Obsolete	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

AT28HC64B-90JU is the direct equivalent from Microchip Technology, maintaining identical electrical performance specifications (90 ns access time, 10ms write cycle) while offering active product status and ROHS3 compliance. This part is recommended as the primary substitute for applications requiring exact performance matching and continued manufacturer support.

X28HC64JIZ-12 and X28HC64JIZ-12T1 from Renesas Electronics provide functional substitution with extended operating temperature range (-40°C to 85°C versus 0°C to 70°C) and improved write cycle time (5ms versus 10ms). These parts are suitable for applications where the 120 ns access time meets system requirements. X28HC64JIZ-12T1 is supplied in Tape & Reel packaging, appropriate for high-volume production environments.

All substitute parts maintain ROHS3 compliance and REACH unaffected status, supporting modern regulatory requirements. Selection should prioritize AT28HC64B-90JU for performance-critical applications requiring exact timing specifications, and Renesas alternatives for applications benefiting from extended temperature range and faster write operations.

Frequently Asked Questions (FAQ)

Q: Can AT28HC64B-90JU replace AT28HC64B-90JC directly?

A: Yes. AT28HC64B-90JU is a direct equivalent with identical memory capacity, organization, access time, write cycle time, supply voltage, and 32-PLCC package. The primary difference is product status (active versus obsolete) and packaging format (tube versus unspecified).

Q: What is the impact of 120 ns access time in Renesas parts versus 90 ns in the original?

A: The 120 ns access time in X28HC64JIZ-12 and X28HC64JIZ-12T1 represents a 30 ns increase in read access delay. Substitution is valid only if system timing budgets accommodate this slower access time. Applications with tight timing constraints should verify compatibility before implementation.

Q: Are the Renesas X28HC64JIZ parts mechanically compatible?

A: Yes. Both X28HC64JIZ-12 and X28HC64JIZ-12T1 use the same 32-PLCC (13.97x11.43) package format, ensuring identical PCB footprint and mounting compatibility with the original AT28HC64B-90JC.

Q: What is the difference between X28HC64JIZ-12 and X28HC64JIZ-12T1?

A: Both parts are electrically identical with 64Kbit capacity, 8K x 8 organization, 120 ns access time, and 5ms write cycle time. The primary difference is packaging: X28HC64JIZ-12 uses standard packaging, while X28HC64JIZ-12T1 is supplied in Tape & Reel format for automated assembly processes.

Q: Does the extended temperature range of substitute parts affect compatibility?

A: The extended operating range (-40°C to 85°C in substitutes versus 0°C to 70°C in the original) provides broader environmental capability. Substitution is fully compatible; the wider range does not introduce incompatibility with systems designed for the original temperature specification.

Q: Are all substitute parts RoHS compliant?

A: Yes. AT28HC64B-90JU, X28HC64JIZ-12, and X28HC64JIZ-12T1 are all ROHS3 compliant. The original AT28HC64B-90JC is RoHS non-compliant, making compliant substitutes necessary for applications subject to RoHS regulations.

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