AT28C64E-25SC Equivalent & Substitute Parts

Part Overview

The AT28C64E-25SC is a 64Kbit parallel EEPROM memory IC manufactured by Microchip Technology in a 28-SOIC package. This device is classified as obsolete and operates with a 250 ns access time and 4.5V to 5.5V supply voltage. Due to its obsolete status and limited availability relative to active alternatives, identifying equivalent substitute parts is essential for ongoing system support and new design implementations.

Key Parameters

Parameter	Value
Memory Size	64Kbit
Memory Organization	8K x 8
Memory Format	EEPROM
Memory Interface	Parallel
Access Time	250 ns
Write Cycle Time	200µs
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package Type	28-SOIC
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the AT28C64E-25SC is determined by the following critical parameters:

Memory capacity and organization (64Kbit, 8K x 8 configuration)
Parallel interface architecture
Package compatibility (28-SOIC form factor)
Supply voltage range (4.5V ~ 5.5V)
Pin-to-pin compatibility

The AT28C64B-15SU qualifies as a direct substitute based on identical memory capacity, organization, interface type, package, and voltage specifications. The substitute maintains full electrical and mechanical compatibility while offering improved performance characteristics and active product status.

Parameter Comparison

Parameter	AT28C64E-25SC	AT28C64B-15SU	Compatibility
Memory Size	64Kbit	64Kbit	Identical
Memory Organization	8K x 8	8K x 8	Identical
Memory Format	EEPROM	EEPROM	Identical
Memory Interface	Parallel	Parallel	Identical
Access Time	250 ns	150 ns	Substitute is faster
Write Cycle Time	200µs	10ms	Substitute is slower
Voltage Supply Range	4.5V ~ 5.5V	4.5V ~ 5.5V	Identical
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	Substitute has wider range
Package Type	28-SOIC	28-SOIC	Identical
Mounting Type	Surface Mount	Surface Mount	Identical
Product Status	Obsolete	Active	Substitute is active
RoHS Status	Non-compliant	ROHS3 Compliant	Substitute is compliant

Engineering Selection Recommendations

The AT28C64B-15SU is the qualified substitute for the AT28C64E-25SC based on the following factors:

Active product status ensures long-term availability and supply chain continuity
ROHS3 compliance meets current environmental and regulatory requirements
Identical memory capacity, organization, and parallel interface ensure functional equivalence
Pin-to-pin compatibility with 28-SOIC package enables direct board-level replacement
Identical supply voltage range (4.5V ~ 5.5V) eliminates power supply modifications
Improved access time (150 ns versus 250 ns) provides performance enhancement
Extended operating temperature range (-40°C ~ 85°C versus 0°C ~ 70°C) supports broader application environments

Frequently Asked Questions (FAQ)

Q: Can the AT28C64B-15SU replace the AT28C64E-25SC in existing designs?

A: Yes. Both devices share identical memory capacity (64Kbit), organization (8K x 8), parallel interface, 28-SOIC package, and supply voltage range (4.5V ~ 5.5V). Pin-to-pin compatibility is maintained, enabling direct substitution without circuit modifications.

Q: What are the performance differences between these parts?

A: The AT28C64B-15SU has a faster access time (150 ns versus 250 ns) and a slower write cycle time (10ms versus 200µs). The substitute also supports a wider operating temperature range (-40°C ~ 85°C versus 0°C ~ 70°C).

Q: Why is the AT28C64E-25SC classified as obsolete?

A: The AT28C64E-25SC has reached end-of-life status. The AT28C64B-15SU is the active equivalent from Microchip Technology and is recommended for new designs and ongoing system support.

Q: Are there packaging differences between these parts?

A: No. Both devices use the 28-SOIC (0.295", 7.50mm Width) package with surface mount mounting type. Board layout and footprints are identical.

Q: Does the AT28C64B-15SU meet current compliance standards?

A: Yes. The AT28C64B-15SU is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. The AT28C64E-25SC is RoHS non-compliant.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message