JS28F064M29EWBA Equivalent & Substitute Parts

Part Overview

The JS28F064M29EWBA is a 64Mbit parallel NOR Flash memory IC manufactured by Micron Technology Inc., housed in a 56-TSOP package. This component operates at 2.7V to 3.6V with a 70ns access time and supports 8M x 8 or 4M x 16 memory organization. The part is classified as obsolete, making identification of compatible substitutes essential for ongoing system support and component procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	JS28F064M29EWBA
Manufacturer	Micron Technology Inc.
Memory Size	64Mbit
Memory Format	FLASH - NOR
Memory Organization	8M x 8, 4M x 16
Memory Interface	Parallel
Access Time	70 ns
Write Cycle Time	70 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
MSL Rating	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution eligibility for the JS28F064M29EWBA is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Memory Interface: Parallel (required for 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)
Mounting Type: Surface Mount (required for assembly process compatibility)

Flexible Parameters (allowing substitution):

Memory Size: Can be equal or greater capacity
Memory Organization: Can differ if total addressable space is maintained or exceeded
Access Time: Can be equal or faster (lower values acceptable)
Write Cycle Time: Can be equal or faster (lower values acceptable)
Product Status: Active parts preferred over obsolete for long-term availability

The MT28EW128ABA1LJS-0SIT meets all mandatory criteria while offering increased memory capacity (128Mbit vs 64Mbit) and improved performance characteristics.

Parameter Comparison

Parameter	JS28F064M29EWBA (Main Part)	MT28EW128ABA1LJS-0SIT (Substitute)
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	70 ns	95 ns
Write Cycle Time	70 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
Product Status	Obsolete	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	3 (168 Hours)	3 (168 Hours)

Engineering Selection Recommendations

The MT28EW128ABA1LJS-0SIT is a qualified substitute for the JS28F064M29EWBA based on the following factors:

Compliance & Certification Alignment: Both parts maintain ROHS3 compliance and identical MSL ratings, ensuring regulatory and manufacturing process compatibility.

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

Electrical & Physical Compatibility: Identical voltage supply ranges, operating temperature specifications, package dimensions, and parallel interface architecture ensure direct functional replacement without circuit redesign.

Memory Capacity Enhancement: The 128Mbit capacity of the substitute provides double the addressable storage space, supporting expanded application requirements without architectural changes.

Performance Characteristics: While access time increases from 70ns to 95ns, write cycle time improves from 70ns to 60ns. System timing analysis is required to confirm compatibility with existing timing constraints.

Frequently Asked Questions (FAQ)

Q: Can the MT28EW128ABA1LJS-0SIT directly replace the JS28F064M29EWBA without PCB modifications?

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

Q: What is the impact of the increased access time (95ns vs 70ns) on system performance?

A: Access time determines the delay from address presentation to data availability. The 25ns increase must be evaluated against your system's timing budget. If the original design operated with timing margin, the substitute may be compatible. If the system operated at the access time limit, timing analysis is necessary.

Q: Are the memory organizations compatible between these parts?

A: The main part supports 8M x 8 or 4M x 16 organization. The substitute supports 16M x 8 or 8M x 16 organization. Address line requirements differ. Firmware or hardware address decoding must accommodate the different organization schemes.

Q: Does the substitute part meet the same environmental and compliance requirements?

A: Yes. Both parts are ROHS3 compliant with identical MSL ratings and operating temperature ranges (-40°C to 85°C). Moisture handling and storage requirements are equivalent.

Q: Why is the substitute part listed as Active while the main part is Obsolete?

A: Product status reflects manufacturer support and availability. Active status indicates ongoing production and supply chain support, while Obsolete status indicates end-of-life with limited or no future availability. The substitute ensures long-term component procurement viability.

Q: Are there any voltage supply differences between these parts?

A: No. Both parts operate within the identical 2.7V to 3.6V supply range, ensuring power supply compatibility without modification.

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