SST39SF040-55-4I-WHE Equivalent & Substitute Parts

Part Overview

The SST39SF040-55-4I-WHE is a 4Mbit parallel FLASH memory IC manufactured by Microchip Technology, part of the SST39 MPF™ series. This non-volatile memory device operates with a 55 ns access time and is housed in a 32-TFSOP surface mount package. The part is currently in active production status with ROHS3 compliance and is suitable for applications requiring reliable parallel FLASH memory with fast access characteristics. Substitute parts may be necessary due to inventory constraints, supply chain considerations, or specific application timing requirements.

Substiute Parts

SST39SF040-55-4I-WHE

Microchip TechnologyIn Stock: 3114SST39SF040-55-4I-WHE Datasheet

Current PartRFQ

SST39SF040-70-4I-WHE

Microchip TechnologyIn Stock: 1443SST39SF040-70-4I-WHE Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SST39SF040-55-4I-WHE is determined by the following critical parameters:

Fixed Parameters (Must Match):

• Memory Size: 4Mbit
• Memory Organization: 512K x 8
• Memory Interface: Parallel
• Voltage Supply: 4.5V ~ 5.5V
• Operating Temperature: -40°C ~ 85°C
• Package Type: 32-TFSOP
• Mounting Type: Surface Mount
• Write Cycle Time: 20µs

Variable Parameters (Allowed Variance):

• Access Time: Slower speeds are acceptable in applications where the 55 ns specification is not a hard requirement

The SST39SF040-70-4I-WHE qualifies as a substitute because it maintains all fixed parameters while featuring a slower 70 ns access time. This part belongs to the same SST39 MPF™ series and shares identical electrical and mechanical specifications except for access time performance.

Parameter Comparison

Engineering Selection Recommendations

Both the SST39SF040-55-4I-WHE and SST39SF040-70-4I-WHE are active production parts with identical compliance certifications. Selection between these parts depends on application timing requirements:

The SST39SF040-55-4I-WHE is the primary choice for applications requiring 55 ns access time performance. The SST39SF040-70-4I-WHE serves as a functional substitute for applications where 70 ns access time is acceptable within system timing margins. Both parts maintain ROHS3 compliance, REACH unaffected status, and identical moisture sensitivity levels, ensuring equivalent reliability and environmental compliance in qualified applications.

Frequently Asked Questions (FAQ)

Q: Can the SST39SF040-70-4I-WHE replace the SST39SF040-55-4I-WHE in my design?

A: The SST39SF040-70-4I-WHE is a valid substitute only if your application timing specifications allow for 70 ns access time instead of 55 ns. All other electrical and mechanical parameters are identical. System-level timing analysis is required to confirm compatibility.

Q: Are there any package differences between these parts?

A: No. Both parts use the identical 32-TFSOP surface mount package with 0.488" width and 12.40mm dimensions. PCB layout and footprints are interchangeable.

Q: Do these parts have different supply voltage requirements?

A: No. Both parts operate within the same 4.5V to 5.5V supply voltage range and share identical operating temperature specifications of -40°C to 85°C.

Q: What is the significance of the access time difference?

A: Access time defines the maximum delay from address setup to valid data output. The 55 ns variant provides faster data retrieval compared to the 70 ns variant. Applications with strict timing requirements must use the 55 ns part; applications with relaxed timing margins may use the 70 ns substitute.

Q: Are both parts RoHS compliant?

A: Yes. Both SST39SF040-55-4I-WHE and SST39SF040-70-4I-WHE are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: What is the write cycle time for both parts?

A: Both parts share an identical write cycle time of 20µs for word and page operations.