MX29F040CQC-90G Equivalent & Substitute Parts

Part Overview

The MX29F040CQC-90G is a 4Mbit parallel NOR FLASH memory IC manufactured by Macronix, housed in a 32-PLCC package with 90 ns access time. This component is classified as discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives for ongoing system support and new designs requiring this memory capacity and interface type.

Substiute Parts

MX29F040CQC-90G

MacronixIn Stock: 1873MX29F040CQC-90G Datasheet

Current PartRFQ

SST39SF040-70-4C-NHE

Microchip TechnologyIn Stock: 8419SST39SF040-70-4C-NHE Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MX29F040CQC-90G is determined by strict equivalence across the following parameters:

• Memory capacity: 4Mbit
• Memory organization: 512K x 8 configuration
• Interface type: Parallel
• Memory technology: FLASH (NOR-type)
• Supply voltage range: 4.5V ~ 5.5V
• Operating temperature range: 0°C ~ 70°C
• Package format: 32-PLCC (J-Lead)
• Mounting configuration: Surface Mount

The SST39SF040-70-4C-NHE meets all substitution criteria. While it features a faster access time (70 ns versus 90 ns), this represents improved performance and does not compromise compatibility in systems designed for the original part's 90 ns specification.

Parameter Comparison

Engineering Selection Recommendations

The SST39SF040-70-4C-NHE is the qualified substitute for the MX29F040CQC-90G. Selection is based on:

• Identical memory capacity, organization, and interface specifications
• Full voltage and temperature range compatibility
• ROHS3 compliance and equivalent moisture sensitivity rating
• Active product status with verified programmability and current inventory availability
• Improved access time performance (70 ns) relative to the original specification (90 ns)
• Minimal package footprint variation (0.08 mm height difference) compatible with existing PCB layouts

Frequently Asked Questions (FAQ)

Q: Can the SST39SF040-70-4C-NHE directly replace the MX29F040CQC-90G in existing designs?

A: Yes. Both parts share identical memory capacity (4Mbit), organization (512K x 8), parallel interface, voltage supply range (4.5V ~ 5.5V), operating temperature range (0°C ~ 70°C), and 32-PLCC package format. The substitute features faster access time (70 ns), which is compatible with systems designed for 90 ns operation.

Q: Are there package compatibility concerns?

A: Package dimensions are nearly identical. The MX29F040CQC-90G measures 11.43 x 14.05 mm, while the SST39SF040-70-4C-NHE measures 11.43 x 13.97 mm. This 0.08 mm height difference is within standard PCB assembly tolerances and does not affect socket or land pattern compatibility.

Q: What is the difference in write cycle time between these parts?

A: The MX29F040CQC-90G specifies 90 ns write cycle time, while the SST39SF040-70-4C-NHE specifies 20 µs. This difference reflects different internal write architecture but does not affect functional compatibility in standard parallel FLASH memory applications.

Q: Are both parts RoHS compliant?

A: Yes. Both the MX29F040CQC-90G and SST39SF040-70-4C-NHE are ROHS3 compliant with identical MSL ratings of 3 (168 Hours).

Q: Why is the original part discontinued?

A: The MX29F040CQC-90G is discontinued at DiGi Electronics. The SST39SF040-70-4C-NHE remains in active production with verified availability and programmability support.