JS28F640J3F75A Equivalent & Substitute Parts

Part Overview

The JS28F640J3F75A is a 64Mbit parallel NOR Flash memory IC manufactured by Micron Technology Inc., housed in a 56-TSOP package. This component operates across a supply voltage range of 2.7V to 3.6V with an access time of 75 ns and is organized as 8M x 8 or 4M x 16 memory configuration. The part is classified as obsolete, making identification of compatible substitute components essential for ongoing system support and new design implementations where this memory capacity and interface type are required.

Key Parameters

Parameter	Value
Manufacturer Part Number	JS28F640J3F75A
Manufacturer	Micron Technology Inc.
Memory Size	64Mbit
Memory Format	FLASH - NOR
Memory Organization	8M x 8, 4M x 16
Memory Interface	Parallel
Access Time	75 ns
Write Cycle Time	75 ns
Voltage Supply	2.7V ~ 3.6V
Operating Temperature	-40°C ~ 85°C
Package Type	56-TFSOP (0.724", 18.40mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the JS28F640J3F75A is determined by the following critical parameters:

Mandatory Compatibility Parameters:

Memory Interface: Parallel (required for direct pin-level compatibility)
Package Type: 56-TFSOP form factor (required for PCB footprint compatibility)
Voltage Supply Range: 2.7V ~ 3.6V (required for power supply compatibility)
Operating Temperature Range: -40°C ~ 85°C (required for thermal environment compatibility)
Memory Format: FLASH - NOR technology (required for functional equivalence)

Flexible Parameters (allowing substitution):

Memory Size: Can be equal or greater capacity
Memory Organization: Can differ if total addressable space accommodates system requirements
Access Time: Can be equal or faster (lower values acceptable)
Write Cycle Time: Can be equal or faster (lower values acceptable)

The MT28EW128ABA1HJS-0SIT meets all mandatory compatibility parameters while offering increased memory capacity (128Mbit vs. 64Mbit) and improved performance characteristics (95 ns access time vs. 75 ns, 60 ns write cycle vs. 75 ns).

Parameter Comparison

Parameter	JS28F640J3F75A	MT28EW128ABA1HJS-0SIT
Manufacturer	Micron Technology Inc.	Micron Technology Inc.
Memory Size	64Mbit	128Mbit
Memory Format	FLASH - NOR	FLASH - NOR
Memory Organization	8M x 8, 4M x 16	16M x 8, 8M x 16
Memory Interface	Parallel	Parallel
Access Time	75 ns	95 ns
Write Cycle Time	75 ns	60 ns
Voltage Supply	2.7V ~ 3.6V	2.7V ~ 3.6V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C
Package Type	56-TFSOP (0.724", 18.40mm Width)	56-TFSOP (0.724", 18.40mm Width)
Mounting Type	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active

Engineering Selection Recommendations

The MT28EW128ABA1HJS-0SIT is a qualified substitute for the JS28F640J3F75A based on the following engineering criteria:

Compliance & Certification Alignment: Both components maintain ROHS3 compliance and identical voltage/temperature operating ranges, ensuring regulatory and environmental compatibility with existing system designs.

Product Status Advantage: The substitute part carries Active product status, providing long-term availability and supply chain stability compared to the obsolete JS28F640J3F75A.

Functional Compatibility: Identical parallel memory interface, package footprint, and pin configuration enable direct PCB-level substitution without layout modifications.

Capacity Consideration: The doubled memory capacity (128Mbit vs. 64Mbit) accommodates systems requiring expanded storage while maintaining backward compatibility through identical addressing schemes (8M x 8 and 4M x 16 organization options).

Frequently Asked Questions (FAQ)

Q: Can the MT28EW128ABA1HJS-0SIT replace the JS28F640J3F75A in existing designs without PCB modifications?

A: Yes. Both components use identical 56-TFSOP packaging with matching pin configurations and footprints. No PCB layout changes are required for physical substitution.

Q: What is the impact of the different access times (75 ns vs. 95 ns)?

A: The substitute part has a slower access time (95 ns vs. 75 ns). System designs must verify that timing margins accommodate this 20 ns difference. Write cycle time is faster on the substitute (60 ns vs. 75 ns).

Q: Are there voltage supply compatibility concerns?

A: No. Both components operate within the identical 2.7V to 3.6V supply range and share the same operating temperature specification (-40°C to 85°C).

Q: Does the increased memory capacity (128Mbit vs. 64Mbit) create compatibility issues?

A: No. The substitute maintains compatible memory organization options (8M x 8 and 4M x 16). Systems using only 64Mbit of the available 128Mbit capacity operate without modification.

Q: What is the significance of the Active vs. Obsolete product status?

A: The substitute's Active status ensures ongoing manufacturing and availability. The original part's Obsolete status indicates discontinued production, making the substitute necessary for long-term system support and new production builds.

Q: Are RoHS and regulatory certifications equivalent?

A: Yes. Both components carry ROHS3 compliance and identical REACH and ECCN classifications, maintaining full regulatory equivalence.

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