AT28C64E-25PI Equivalent & Substitute Parts

Part Overview

The AT28C64E-25PI is a 64Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-DIP package. This device features 8K x 8 memory organization with a 250 ns access time and operates across a 4.5V to 5.5V supply voltage range. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations where this specific model is no longer available through standard distribution channels.

Key Parameters

Parameter	Value
Memory Type	Non-Volatile EEPROM
Memory Size	64Kbit
Memory Organization	8K x 8
Memory Interface	Parallel
Access Time	250 ns
Write Cycle Time	200µs
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package Type	28-DIP (0.600", 15.24mm)
Mounting Type	Through Hole

Substitute Part Grouping Explanation

Substitution for the AT28C64E-25PI is determined by strict equivalence across the following critical parameters:

Memory capacity: 64Kbit (8K x 8 organization)
Interface type: Parallel
Package format: 28-DIP with identical pin configuration
Supply voltage compatibility: 4.5V ~ 5.5V range
Non-volatile EEPROM technology

The identified substitute parts maintain these core electrical and mechanical specifications, ensuring functional compatibility in existing circuit designs. Differences in access time and write cycle time represent performance improvements rather than compatibility barriers, as faster devices operate within the timing requirements of systems designed for the original part.

Parameter Comparison

Parameter	AT28C64E-25PI	AT28C64B-15PU	X28HC64PZ-12
Manufacturer	Microchip Technology	Microchip Technology	Renesas Electronics
Memory Size	64Kbit	64Kbit	64Kbit
Memory Organization	8K x 8	8K x 8	8K x 8
Memory Interface	Parallel	Parallel	Parallel
Access Time	250 ns	150 ns	120 ns
Write Cycle Time	200µs	10ms	5ms
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Package / Case	28-DIP (0.600", 15.24mm)	28-DIP (0.600", 15.24mm)	28-DIP (0.600", 15.24mm)
Mounting Type	Through Hole	Through Hole	Through Hole
Product Status	Obsolete	Active	Active
RoHS Compliance	Non-compliant	ROHS3 Compliant	ROHS3 Compliant
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	0°C ~ 70°C

Engineering Selection Recommendations

AT28C64B-15PU is the primary substitute from Microchip Technology. This part maintains identical memory capacity, organization, and electrical specifications while offering improved access time (150 ns versus 250 ns). The device is currently in active production status with ROHS3 compliance certification. Operating temperature range matches the original part (-40°C to 85°C), ensuring compatibility across equivalent thermal environments. Inventory availability is substantial at 3308 units.

X28HC64PZ-12 from Renesas Electronics provides an alternative substitute with the fastest access time (120 ns) and shortest write cycle time (5ms). This part is ROHS3 compliant and actively produced. The operating temperature range is restricted to 0°C to 70°C, which represents a narrower specification than the original part. This device is suitable for applications operating within this temperature window. Inventory availability is 2050 units.

Both substitute parts are actively manufactured and RoHS compliant, addressing the obsolescence status of the original AT28C64E-25PI while providing improved performance characteristics and regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can AT28C64B-15PU directly replace AT28C64E-25PI in existing designs?

A: Yes. Both devices share identical 64Kbit capacity, 8K x 8 organization, parallel interface, 28-DIP package, and 4.5V to 5.5V supply voltage specification. The faster access time (150 ns) of the substitute part is a performance improvement that does not create compatibility issues.

Q: What is the primary difference between AT28C64B-15PU and X28HC64PZ-12?

A: Both are functionally equivalent 64Kbit parallel EEPROMs in 28-DIP packages. The X28HC64PZ-12 offers faster access time (120 ns) and write cycle time (5ms) compared to AT28C64B-15PU (150 ns and 10ms respectively). The X28HC64PZ-12 has a restricted operating temperature range (0°C to 70°C) versus AT28C64B-15PU (-40°C to 85°C).

Q: Are there temperature considerations when selecting a substitute?

A: The original AT28C64E-25PI operates from -40°C to 85°C. AT28C64B-15PU maintains this full range. X28HC64PZ-12 operates only from 0°C to 70°C. Select X28HC64PZ-12 only if your application operates within this narrower temperature window.

Q: Do the substitute parts require different PCB footprints?

A: No. Both substitute parts use the standard 28-DIP package (0.600", 15.24mm) with identical pin configuration and through-hole mounting, requiring no PCB modifications.

Q: What is the compliance status of the substitute parts?

A: Both AT28C64B-15PU and X28HC64PZ-12 are ROHS3 compliant, addressing the non-compliant status of the obsolete AT28C64E-25PI for applications requiring regulatory compliance.

Q: Which substitute part should be selected for new designs?

A: AT28C64B-15PU is recommended for new designs due to its active production status, full temperature range compatibility (-40°C to 85°C), and substantial inventory availability. X28HC64PZ-12 is suitable as an alternative when faster access time is beneficial and operating temperature remains within 0°C to 70°C.

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