CAT28C64BWI12 Equivalent & Substitute Parts

Part Overview

The CAT28C64BWI12 is a 64Kbit parallel EEPROM memory IC manufactured by onsemi in 28-SOIC surface mount packaging. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing system support and new design implementations. The part operates across the industrial temperature range of -40°C to 85°C with a 120 ns access time and 5ms write cycle time, serving applications requiring non-volatile parallel memory storage.

Key Parameters

Parameter	Value
Memory Size	64Kbit
Memory Organization	8K x 8
Memory Interface	Parallel
Access Time	120 ns
Write Cycle Time	5ms
Voltage Supply	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package	28-SOIC (0.295", 7.50mm Width)
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution for the CAT28C64BWI12 is determined by strict electrical and mechanical compatibility across the following parameters: memory capacity (64Kbit), memory organization (8K x 8), parallel interface architecture, package type (28-SOIC), supply voltage range (4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C). All substitute parts listed maintain identical memory specifications and physical packaging. Access time variations among substitutes (70 ns to 150 ns) represent performance enhancements or alternatives; parts with equal or faster access times than the original 120 ns specification are directly compatible. Write cycle time differences (10ms for substitutes versus 5ms for the original) do not prevent substitution in applications where write performance is not timing-critical. All substitute parts are manufactured by Microchip Technology and carry active product status with verified programmability.

Parameter Comparison

Parameter	CAT28C64BWI12	AT28C64B-15SU	AT28HC64B-12SU	AT28HC64B-70SU	AT28HC64B-90SU	AT28HC64BF-12SU
Manufacturer	onsemi	Microchip Technology	Microchip Technology	Microchip Technology	Microchip Technology	Microchip Technology
Memory Size	64Kbit	64Kbit	64Kbit	64Kbit	64Kbit	64Kbit
Memory Organization	8K x 8	8K x 8	8K x 8	8K x 8	8K x 8	8K x 8
Memory Interface	Parallel	Parallel	Parallel	Parallel	Parallel	Parallel
Access Time	120 ns	150 ns	120 ns	70 ns	90 ns	120 ns
Write Cycle Time	5ms	10ms	10ms	10ms	10ms	10ms
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	28-SOIC	28-SOIC	28-SOIC	28-SOIC	28-SOIC	28-SOIC
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All five Microchip Technology substitute parts maintain full electrical and mechanical compatibility with the CAT28C64BWI12. Selection among substitutes depends on specific application requirements and compliance mandates.

For applications requiring matching or improved access time performance, AT28HC64B-70SU (70 ns) and AT28HC64B-90SU (90 ns) provide faster operation than the original specification. AT28HC64B-12SU and AT28HC64BF-12SU both match the original 120 ns access time. AT28C64B-15SU operates at 150 ns, representing the slowest option among available substitutes.

All substitute parts carry active product status and ROHS3 compliance certification, ensuring long-term availability and environmental regulatory alignment. Moisture sensitivity levels vary across the substitute family (MSL 2 or MSL 3), with AT28HC64B-12SU and AT28HC64BF-12SU rated at MSL 2 (1 Year) offering superior moisture protection compared to MSL 3 alternatives.

The extended write cycle time of 10ms in all substitutes versus the original 5ms specification does not affect functional compatibility in standard EEPROM applications where write operations are not timing-constrained.

Frequently Asked Questions (FAQ)

Q: Can AT28C64B-15SU replace CAT28C64BWI12 in existing designs? A: Yes. AT28C64B-15SU maintains identical memory capacity, organization, parallel interface, package type, and voltage specifications. The 150 ns access time is slower than the original 120 ns specification but remains functionally compatible for applications not requiring faster read performance.

Q: What is the difference between AT28HC64B-12SU and AT28HC64BF-12SU? A: Both parts share identical electrical specifications including 120 ns access time, 64Kbit capacity, and 28-SOIC packaging. The primary difference is moisture sensitivity level: AT28HC64B-12SU is rated MSL 2 (1 Year) while AT28HC64BF-12SU is also MSL 2 (1 Year). Both are suitable for equivalent substitution.

Q: Does the 10ms write cycle time in substitutes affect system performance? A: The extended write cycle time from 5ms to 10ms does not impact functional compatibility. Applications should evaluate whether write operation timing is critical to system requirements. In most EEPROM applications, write cycle time is not a performance-limiting factor.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All five Microchip Technology substitute parts carry ROHS3 compliance certification, meeting environmental and regulatory requirements for current manufacturing standards.

Q: Which substitute offers the fastest access time? A: AT28HC64B-70SU provides the fastest access time at 70 ns, representing a 50 ns improvement over the original CAT28C64BWI12 specification of 120 ns.

Q: Can I use AT28HC64B-70SU as a direct pin-compatible replacement? A: Yes. AT28HC64B-70SU maintains identical 28-SOIC package dimensions, pin configuration, voltage specifications, and operating temperature range as the original part, enabling direct socket substitution.

Q: What inventory levels are available for each substitute? A: AT28C64B-15SU: 17,844 pcs; AT28HC64B-12SU: 2,200 pcs; AT28HC64B-70SU: 2,400 pcs; AT28HC64B-90SU: 1,330 pcs; AT28HC64BF-12SU: 2,136 pcs.

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