AT28C64-20PI Equivalent & Substitute Parts

Part Overview

The AT28C64-20PI is a 64Kbit parallel EEPROM memory IC manufactured by Microchip Technology, housed in a 28-DIP package with 200 ns access time. This part is classified as obsolete, which necessitates identification of functionally equivalent alternatives for ongoing system support and new designs. The AT28C64-20PI operates within the 4.5V to 5.5V supply voltage range and supports standard parallel memory interface protocols suitable for legacy embedded systems and industrial applications.

Key Parameters

Parameter	Value
Memory Type	Non-Volatile EEPROM
Memory Size	64Kbit
Memory Organization	8K x 8
Memory Interface	Parallel
Access Time	200 ns
Write Cycle Time	1 ms
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 of the AT28C64-20PI is determined by strict equivalence across the following critical parameters:

Memory capacity: 64Kbit (8K x 8 organization)
Memory type: Non-volatile EEPROM with parallel interface
Voltage supply: 4.5V ~ 5.5V compatibility
Package: 28-DIP form factor with identical pinout
Operating temperature range: -40°C ~ 85°C
Access time: Equal to or faster than 200 ns
Write cycle time: Compatible with system timing requirements

The AT28C64B-15PU meets all substitution criteria. It maintains identical memory capacity, organization, voltage specifications, package configuration, and operating temperature range. The faster 150 ns access time and improved write cycle time (10 ms) provide enhanced performance characteristics while maintaining full backward compatibility with AT28C64-20PI applications.

Parameter Comparison

Parameter	AT28C64-20PI	AT28C64B-15PU	Compatibility
Memory Size	64Kbit	64Kbit	Identical
Memory Organization	8K x 8	8K x 8	Identical
Memory Interface	Parallel	Parallel	Identical
Access Time	200 ns	150 ns	Faster (Compatible)
Write Cycle Time	1 ms	10 ms	Slower (Compatible)
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	Identical
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	Identical
Package / Case	28-DIP (0.600", 15.24mm)	28-DIP (0.600", 15.24mm)	Identical
Mounting Type	Through Hole	Through Hole	Identical

Engineering Selection Recommendations

The AT28C64B-15PU is the qualified substitute for AT28C64-20PI applications. The primary distinction between these parts is product status: AT28C64-20PI is obsolete, while AT28C64B-15PU maintains active status with verified programmability. The AT28C64B-15PU carries ROHS3 compliance certification, whereas the AT28C64-20PI is RoHS non-compliant. Both parts maintain REACH unaffected status and identical ECCN/HTSUS classifications.

For new designs and system replacements, AT28C64B-15PU is the appropriate selection due to active product status and regulatory compliance. The improved access time (150 ns versus 200 ns) provides performance margin without requiring circuit modifications. The extended write cycle time (10 ms versus 1 ms) remains compatible with standard parallel EEPROM interface protocols and does not impact system functionality in typical applications.

Frequently Asked Questions (FAQ)

Q: Can AT28C64B-15PU directly replace AT28C64-20PI in existing circuits?

A: Yes. Both parts share identical pinout, package dimensions, voltage specifications, and operating temperature range. No circuit modifications are required for direct substitution.

Q: What is the significance of the access time difference (200 ns vs. 150 ns)?

A: The AT28C64B-15PU has faster access time, meaning data is available more quickly after address presentation. This is a performance improvement that maintains backward compatibility with systems designed for the slower 200 ns specification.

Q: Why does AT28C64B-15PU have a longer write cycle time (10 ms vs. 1 ms)?

A: Write cycle time represents the duration required to complete an internal write operation. The longer cycle time in AT28C64B-15PU does not affect system compatibility, as parallel EEPROM interfaces accommodate variable write durations through status polling or timing protocols.

Q: Are there packaging differences between these parts?

A: Both parts use 28-DIP through-hole packages with identical physical dimensions (0.600", 15.24mm). AT28C64B-15PU is supplied in tube packaging, while AT28C64-20PI packaging is not specified. This does not affect electrical or mechanical compatibility.

Q: What compliance certifications differ between these parts?

A: AT28C64B-15PU is ROHS3 compliant, while AT28C64-20PI is RoHS non-compliant. Both maintain REACH unaffected status. For applications subject to RoHS requirements, AT28C64B-15PU is the mandated selection.

Q: Is AT28C64B-15PU suitable for -40°C to 85°C temperature range applications?

A: Yes. AT28C64B-15PU maintains the identical -40°C to 85°C operating temperature specification as AT28C64-20PI.

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