AT28C256-15JC Equivalent & Substitute Parts

Part Overview

The AT28C256-15JC is a 256Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 32-PLCC package with 150 ns access time. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new designs. The AT28C256-15JC operates within the industrial temperature range of 0°C to 70°C and requires a 4.5V to 5.5V supply voltage. Substitute parts must maintain functional compatibility across memory capacity, organization, interface type, and physical packaging while accommodating variations in access time, write cycle performance, and operating temperature ranges.

Key Parameters

Parameter	AT28C256-15JC
Memory Size	256Kbit
Memory Organization	32K x 8
Memory Interface	Parallel
Access Time	150 ns
Write Cycle Time	10 ms
Voltage Supply	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package Type	32-PLCC (13.97x11.43)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the AT28C256-15JC is determined by strict adherence to the following electrical and mechanical parameters:

Core Compatibility Requirements:

Memory capacity: 256Kbit (non-negotiable)
Memory organization: 32K x 8 (non-negotiable)
Memory interface: Parallel (non-negotiable)
Package type: 32-PLCC (non-negotiable)
Supply voltage: 4.5V ~ 5.5V (non-negotiable)

Variable Parameters Allowing Substitution:

Access time: Equal to or faster than 150 ns
Write cycle time: Equal to or faster than 10 ms
Operating temperature range: May extend beyond 0°C ~ 70°C
Product status: Active parts preferred over obsolete
RoHS compliance: ROHS3 compliant parts preferred
Packaging format: Tube or Tape & Reel acceptable

Substitute parts are grouped by manufacturer and access time performance. All listed substitutes maintain the core electrical and mechanical compatibility required for direct functional replacement.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Organization	Access Time (ns)	Write Cycle (ms)	Voltage Supply	Temp Range (°C)	Package	Status	RoHS
AT28C256-15JC	Microchip	256Kbit	32K x 8	150	10	4.5-5.5V	0 ~ 70	32-PLCC	Obsolete	Non-compliant
AT28C256-15JU	Microchip	256Kbit	32K x 8	150	10	4.5-5.5V	-40 ~ 85	32-PLCC	Active	ROHS3
AT28HC256F-12JC	Microchip	256Kbit	32K x 8	120	3	4.5-5.5V	0 ~ 70	32-PLCC	Active	Non-compliant
X28HC256JIZ-15T1	Renesas	256Kbit	32K x 8	150	5	4.5-5.5V	-40 ~ 85	32-PLCC	Active	ROHS3
X28HC256JIZ-90T1	Renesas	256Kbit	32K x 8	90	5	4.5-5.5V	-40 ~ 85	32-PLCC	Active	ROHS3
X28HC256JZ-15T1	Renesas	256Kbit	32K x 8	150	5	4.5-5.5V	0 ~ 70	32-PLCC	Active	ROHS3

Engineering Selection Recommendations

For Direct Replacement (Identical Operating Temperature): AT28C256-15JU is the primary substitute when the original 0°C to 70°C operating range is required. This part maintains electrical equivalence while offering active product status and ROHS3 compliance. The extended temperature capability (-40°C to 85°C) provides additional operational margin without affecting performance in the original temperature window.

For Enhanced Performance (Faster Access Time): AT28HC256F-12JC delivers 120 ns access time and 3 ms write cycle time, both superior to the original 150 ns and 10 ms specifications. This part maintains the 0°C to 70°C temperature range but carries non-compliant RoHS status. Selection of this part is appropriate when faster memory access improves system performance and RoHS compliance is not a design requirement.

For Extended Temperature Range: X28HC256JIZ-15T1 and X28HC256JIZ-90T1 (Renesas) provide -40°C to 85°C operating range with ROHS3 compliance. The JIZ-15T1 variant matches the original 150 ns access time, while the JIZ-90T1 variant offers 90 ns access time. Both parts feature 5 ms write cycle time and are supplied in Tape & Reel packaging.

For Industrial Temperature Compatibility: X28HC256JZ-15T1 maintains the 0°C to 70°C operating range with 150 ns access time, matching the original electrical specifications while providing active status and ROHS3 compliance. This part is supplied in Tape & Reel format.

Frequently Asked Questions (FAQ)

Q: Can AT28C256-15JU replace AT28C256-15JC directly? A: Yes. Both parts share identical memory capacity (256Kbit), organization (32K x 8), access time (150 ns), supply voltage (4.5V ~ 5.5V), and 32-PLCC package. The AT28C256-15JU extends the operating temperature range to -40°C to 85°C and carries ROHS3 compliance. Direct substitution is functionally equivalent within the original 0°C to 70°C operating window.

Q: What is the difference between Microchip and Renesas substitute options? A: Both manufacturers provide 256Kbit parallel EEPROM devices in 32-PLCC packages with compatible electrical specifications. Microchip AT28C256-15JU and AT28HC256F-12JC are supplied in Tube packaging. Renesas X28HC256 variants are supplied in Tape & Reel format. Selection depends on packaging requirements, temperature range needs, and access time performance specifications.

Q: Can I use AT28HC256F-12JC as a substitute if my system requires 0°C to 70°C operation? A: Yes. AT28HC256F-12JC operates within the 0°C to 70°C range and provides faster access time (120 ns) and write cycle performance (3 ms) than the original part. The primary consideration is RoHS compliance status; this part is non-compliant, which may affect design certification requirements.

Q: What is the significance of access time differences between substitute parts? A: Access time determines the speed at which data is retrieved from the memory. The original AT28C256-15JC specifies 150 ns. Substitute parts with equal or faster access times (120 ns, 90 ns) are functionally compatible and will not cause timing violations in systems designed for 150 ns operation. Faster access times provide performance margin but do not require system redesign.

Q: Are Tape & Reel packaged parts (Renesas X28HC256 series) compatible with systems designed for Tube packaging? A: Yes. Tape & Reel and Tube packaging formats contain identical die and electrical specifications. The packaging difference affects component handling and assembly processes only. The physical part dimensions, pinout, and electrical performance remain identical.

Q: Which substitute part offers the best compliance profile? A: AT28C256-15JU, X28HC256JIZ-15T1, X28HC256JIZ-90T1, and X28HC256JZ-15T1 all carry ROHS3 compliance. AT28C256-15JU and X28HC256JZ-15T1 maintain the original 0°C to 70°C operating range. The Renesas JIZ variants extend temperature range to -40°C to 85°C. Selection depends on whether extended temperature capability is required for your application.

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