AT49F040-90TI Equivalent & Substitute Parts

Part Overview

The AT49F040-90TI is a 4Mbit parallel FLASH memory IC manufactured by Microchip Technology, housed in a 32-TFSOP package with 90 ns access time. This device is classified as obsolete, making equivalent substitute parts necessary for new designs, production continuity, and system upgrades. The part operates across a 4.5V to 5.5V supply range and supports industrial temperature specifications from -40°C to 85°C.

Key Parameters

Parameter	Value
Memory Size	4Mbit
Memory Organization	512K x 8
Memory Interface	Parallel
Access Time	90 ns
Voltage Supply Range	4.5V ~ 5.5V
Package Type	32-TFSOP
Write Cycle Time	50µs
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution for the AT49F040-90TI is determined by strict alignment of electrical and mechanical parameters:

Critical Matching Parameters:

Memory capacity: 4Mbit
Memory organization: 512K x 8
Interface type: Parallel
Access time: 90 ns (or faster)
Supply voltage: 4.5V ~ 5.5V
Package: 32-TFSOP
Technology: FLASH (NOR-type acceptable)

The substitute parts identified below meet all critical parameters. Both MX29F040CTC variants from Macronix maintain identical memory specifications, voltage requirements, and package form factors. The MX29F040CTC-90G variant matches the 90 ns access time specification exactly, while the MX29F040CTC-70G offers improved performance with 70 ns access time, remaining fully compatible with AT49F040-90TI applications.

Parameter Comparison

Parameter	AT49F040-90TI	MX29F040CTC-70G	MX29F040CTC-90G
Manufacturer	Microchip Technology	Macronix	Macronix
Memory Size	4Mbit	4Mbit	4Mbit
Memory Organization	512K x 8	512K x 8	512K x 8
Memory Interface	Parallel	Parallel	Parallel
Access Time	90 ns	70 ns	90 ns
Write Cycle Time	50µs	70 ns	90 ns
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	0°C ~ 70°C	0°C ~ 70°C
Package Type	32-TFSOP	32-TFSOP	32-TFSOP
Product Status	Obsolete	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)

Engineering Selection Recommendations

MX29F040CTC-90G is the primary substitute for direct replacement of AT49F040-90TI. This part maintains identical 90 ns access time specification and is actively manufactured by Macronix. The device is ROHS3 compliant, addressing environmental regulatory requirements that the obsolete AT49F040-90TI does not meet. Supply availability is confirmed at 2510 pieces in stock.

MX29F040CTC-70G serves as an enhanced alternative where improved performance is acceptable. The 70 ns access time provides faster operation than the original specification while maintaining full electrical and mechanical compatibility. This variant is also ROHS3 compliant and actively produced, with 631 pieces available.

Both Macronix substitutes operate within the identical 4.5V to 5.5V supply range and use the same 32-TFSOP package footprint. Operating temperature ranges for the Macronix parts (0°C to 70°C) are narrower than the AT49F040-90TI (-40°C to 85°C); applications requiring extended temperature operation must account for this specification difference.

Frequently Asked Questions (FAQ)

Q: Can MX29F040CTC-70G replace AT49F040-90TI in all applications?

A: Yes, from an electrical and mechanical standpoint. The MX29F040CTC-70G provides faster access time (70 ns vs. 90 ns), which is backward compatible. However, verify that your application's operating temperature range does not exceed 0°C to 70°C, as the Macronix part has a narrower temperature specification than the original Microchip device.

Q: What is the difference between MX29F040CTC-70G and MX29F040CTC-90G?

A: Both parts are electrically and mechanically identical except for access time. The -70G variant operates at 70 ns access time, while the -90G variant matches the original AT49F040-90TI at 90 ns. Choose based on your system's timing requirements and performance needs.

Q: Are the Macronix substitutes pin-compatible with AT49F040-90TI?

A: Yes. Both MX29F040CTC variants use the same 32-TFSOP package with identical pinout and electrical interface specifications. Direct PCB substitution is supported without layout modifications.

Q: Why is RoHS compliance important for this substitution?

A: The AT49F040-90TI is RoHS non-compliant, while both Macronix substitutes are ROHS3 compliant. For new designs and products subject to environmental regulations, ROHS3 compliance is mandatory in many markets. This makes the Macronix parts the appropriate choice for regulatory compliance.

Q: What is the moisture sensitivity level, and does it affect handling?

A: Both the original and substitute parts carry MSL 3 (168 Hours) rating. This means the component can be exposed to ambient conditions for up to 168 hours before soldering. Standard moisture-controlled storage and handling procedures apply to all three parts.

Q: Are there any other compatible substitutes listed?

A: The MX29F040CTC-70G specification sheet references additional compatible variants including MX29F040CTI-70G and SST39SF040-70-4C-WHE. These maintain the same core electrical specifications and package type, though detailed parameter verification is required for each alternative.

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