AT45DB321D-SU-2.5 Equivalent & Substitute Parts

Part Overview

The AT45DB321D-SU-2.5 is a 32Mbit Serial Peripheral Interface (SPI) FLASH memory IC manufactured by Renesas Electronics Corporation, housed in an 8-SOIC surface mount package. This device operates at 50 MHz with a supply voltage range of 2.5V to 3.6V and is rated for industrial temperature ranges (-40°C to 85°C). The part is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Memory Size	32Mbit
Memory Format	FLASH
Memory Interface	SPI
Clock Frequency	50 MHz
Memory Organization	528 Bytes x 8192 pages
Voltage Supply Range	2.5V ~ 3.6V
Operating Temperature	-40°C ~ 85°C
Package / Case	8-SOIC (0.209", 5.30mm Width)
Mounting Type	Surface Mount
Write Cycle Time (Page)	6ms

Substitute Part Grouping Explanation

Substitution for the AT45DB321D-SU-2.5 is determined by the following critical parameters:

Memory Capacity: 32Mbit (fixed requirement)
Interface Protocol: SPI (fixed requirement)
Package Type: 8-SOIC with 5.30mm width (fixed requirement)
Operating Temperature Range: -40°C to 85°C (fixed requirement)
Supply Voltage Compatibility: Minimum 2.5V support required

Substitute parts must maintain identical memory capacity, SPI interface, and physical package specifications. Clock frequency, write cycle time, and supply voltage upper limits may vary within acceptable ranges. All substitute parts listed are manufactured by Renesas Electronics Corporation and maintain the same base product family lineage (AT45DB321 or AT25DF321 series).

Parameter Comparison

Part Number	Status	Clock Frequency	Memory Organization	Voltage Supply	Write Cycle (Page)	Packaging	Inventory
AT45DB321D-SU-2.5	Obsolete	50 MHz	528 Bytes x 8192 pages	2.5V ~ 3.6V	6ms	8-SOIC	3168 Pcs
AT45DB321E-SHF-T	Active	85 MHz	528 Bytes x 8192 pages	2.3V ~ 3.6V	4ms	Cut Tape (CT) & Digi-Reel®	14200 Pcs
AT45DB321E-SHF-B	Active	85 MHz	528 Bytes x 8192 pages	2.3V ~ 3.6V	4ms	Tube	1287 Pcs
AT45DB321E-SHFHA-T	Active	85 MHz	528 Bytes x 8192 pages	2.3V ~ 3.6V	4ms	Tape & Reel (TR)	2504 Pcs
AT25DF321A-SH-B	Active	100 MHz	256 Bytes x 16384 pages	2.7V ~ 3.6V	3ms	Tube	1695 Pcs
AT45DQ321-SHF-B	Active	104 MHz	528 Bytes x 8192 pages	2.3V ~ 3.6V	4ms	Tube	46204 Pcs

Engineering Selection Recommendations

Primary Substitutes (AT45DB321E Series)

The AT45DB321E-SHF-T, AT45DB321E-SHF-B, and AT45DB321E-SHFHA-T are direct functional equivalents with active product status. These parts maintain identical memory organization (528 Bytes x 8192 pages) and SPI interface specifications. All three are ROHS3 compliant and REACH unaffected. The AT45DB321E-SHF-T offers the highest inventory availability (14200 Pcs) and is verified for DiGi-Electronics programmability. Selection between these three variants depends on packaging requirements: Cut Tape & Digi-Reel for automated assembly, Tube for manual handling, or Tape & Reel for high-volume production.

Secondary Substitute (AT45DQ321-SHF-B)

The AT45DQ321-SHF-B provides the highest clock frequency (104 MHz) and largest inventory stock (46204 Pcs) among all substitutes. It maintains identical memory organization and SPI interface. This part is ROHS3 compliant and REACH unaffected but is not verified for DiGi-Electronics programmability.

Alternative Substitute (AT25DF321A-SH-B)

The AT25DF321A-SH-B operates at 100 MHz with improved write cycle time (3ms page write). However, this part uses different memory organization (256 Bytes x 16384 pages) and requires minimum 2.7V supply voltage. This part is suitable only if the application can accommodate the alternative memory architecture and higher minimum voltage requirement. It is ROHS3 compliant and REACH unaffected.

Frequently Asked Questions (FAQ)

Q: Can AT45DB321E-SHF-T directly replace AT45DB321D-SU-2.5 in existing designs?

A: Yes. Both parts share identical 32Mbit capacity, SPI interface, 8-SOIC package, and memory organization (528 Bytes x 8192 pages). The AT45DB321E-SHF-T operates at higher clock frequency (85 MHz vs. 50 MHz) and lower minimum supply voltage (2.3V vs. 2.5V), making it functionally compatible. Verify that your application can tolerate the faster write cycle time (4ms vs. 6ms).

Q: What is the difference between AT45DB321E-SHF-T, AT45DB321E-SHF-B, and AT45DB321E-SHFHA-T?

A: These three parts are electrically identical. The differences are packaging only: AT45DB321E-SHF-T is supplied in Cut Tape & Digi-Reel format for automated pick-and-place assembly; AT45DB321E-SHF-B is supplied in Tube format for manual handling; AT45DB321E-SHFHA-T is supplied in Tape & Reel format for high-volume production runs.

Q: Is AT25DF321A-SH-B compatible with AT45DB321D-SU-2.5?

A: Electrical compatibility exists for SPI protocol and 32Mbit capacity. However, memory organization differs (256 Bytes x 16384 pages vs. 528 Bytes x 8192 pages), and minimum supply voltage is higher (2.7V vs. 2.5V). Use this part only if your application firmware can accommodate the alternative page structure and your power supply guarantees minimum 2.7V operation.

Q: Why does AT45DQ321-SHF-B have the largest inventory?

A: The AT45DQ321-SHF-B is an active production part with the highest clock frequency (104 MHz) in the substitute group, making it suitable for a broader range of applications. Its large inventory (46204 Pcs) reflects current market demand and production allocation.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (AT45DB321E-SHF-T, AT45DB321E-SHF-B, AT45DB321E-SHFHA-T, AT25DF321A-SH-B, and AT45DQ321-SHF-B) are ROHS3 compliant and REACH unaffected.

Q: What does "DiGi-Electronics Programmable: Verified" mean?

A: This certification indicates that the part has been tested and verified by DiGi-Electronics for compatibility with their programming and verification equipment. AT45DB321E-SHF-T carries this verification; other substitutes may not, which may affect programming workflow in high-volume manufacturing environments.

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