AT25SF321-SHD-B Equivalent & Substitute Parts

Part Overview

The AT25SF321-SHD-B is a 32Mbit NOR Flash memory IC with SPI Quad I/O interface manufactured by Renesas Electronics Corporation. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The part is packaged in 8-SOIC form factor and operates across industrial temperature ranges (-40°C to 85°C).

Key Parameters

Parameter	Value
Memory Size	32Mbit
Memory Format	FLASH - NOR
Memory Interface	SPI - Quad I/O
Memory Organization	4M x 8
Clock Frequency	104 MHz
Package / Case	8-SOIC (0.209", 5.30mm Width)
Voltage Supply Range	2.5V ~ 3.6V
Operating Temperature	-40°C ~ 85°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the AT25SF321-SHD-B is determined by the following critical parameters:

Memory capacity: 32Mbit (4M x 8 organization)
Interface protocol: SPI with Quad I/O capability
Package type: 8-SOIC with identical 5.30mm width
Supply voltage compatibility: Minimum 2.5V operation required
Temperature range: -40°C to 85°C industrial grade
RoHS3 compliance and REACH unaffected status

The substitute parts listed below meet these core electrical and mechanical requirements. Differences in clock frequency, write cycle times, and voltage supply upper limits do not preclude substitution when the substitute part's specifications encompass or exceed the original part's operational envelope.

Parameter Comparison

Parameter	AT25SF321-SHD-B	AT25SF321B-SHB-B	AT25FF321A-SHN-B	W25Q32JVSSIQ
Manufacturer	Renesas Electronics	Renesas Electronics	Renesas Electronics	Winbond Electronics
Memory Size	32Mbit	32Mbit	32Mbit	32Mbit
Memory Format	FLASH - NOR	FLASH - NOR	FLASH - NOR	FLASH - NOR
Memory Interface	SPI - Quad I/O	SPI - Quad I/O	SPI - Quad I/O	SPI - Quad I/O
Memory Organization	4M x 8	4M x 8	4M x 8	4M x 8
Clock Frequency	104 MHz	108 MHz	104 MHz	133 MHz
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Voltage Supply Range	2.5V ~ 3.6V	2.7V ~ 3.6V	1.65V ~ 3.6V	2.7V ~ 3.6V
Operating Temperature	-40°C ~ 85°C (TC)	-40°C ~ 85°C (TC)	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)
Product Status	Obsolete	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	3 (168 Hours)

Engineering Selection Recommendations

All three substitute parts are active products with current manufacturing status, providing long-term availability compared to the obsolete AT25SF321-SHD-B.

AT25SF321B-SHB-B is a direct Renesas successor within the same product family. It maintains identical memory capacity, interface protocol, and package specifications while offering improved clock frequency (108 MHz) and reduced page write cycle time (3ms vs. 5ms). The minimum supply voltage increases to 2.7V, which may require circuit evaluation if 2.5V operation is critical.

AT25FF321A-SHN-B is a Renesas-recommended alternative that extends the lower voltage limit to 1.65V, providing enhanced compatibility with low-power applications. Clock frequency and memory organization remain equivalent to the original part. Write cycle time specifications are not provided in the available data.

W25Q32JVSSIQ is a Winbond cross-manufacturer substitute offering the highest clock frequency (133 MHz) and fastest page write cycle time (3ms). It operates within the 2.7V to 3.6V supply range and maintains full SPI Quad I/O compatibility. Moisture sensitivity level is rated at MSL 3 (168 hours), requiring appropriate handling during storage and assembly compared to MSL 1 for Renesas alternatives.

Frequently Asked Questions (FAQ)

Q: Can AT25SF321B-SHB-B directly replace AT25SF321-SHD-B in existing designs?

A: Yes. Both parts share identical memory capacity (32Mbit), interface (SPI Quad I/O), package (8-SOIC), and temperature range (-40°C to 85°C). The primary design consideration is the minimum supply voltage increase from 2.5V to 2.7V. If your circuit operates at 2.5V, this substitute requires voltage adjustment or selection of AT25FF321A-SHN-B instead.

Q: What are the advantages of W25Q32JVSSIQ over Renesas alternatives?

A: W25Q32JVSSIQ provides higher clock frequency (133 MHz vs. 104-108 MHz) and faster page write performance (3ms). These specifications enable higher data throughput in applications requiring rapid memory access. The trade-off is higher moisture sensitivity (MSL 3 vs. MSL 1), requiring stricter handling protocols during manufacturing.

Q: Is AT25FF321A-SHN-B suitable for low-voltage applications?

A: Yes. AT25FF321A-SHN-B supports operation down to 1.65V, making it the preferred choice for battery-powered or ultra-low-power designs. It maintains the same 32Mbit capacity and SPI Quad I/O interface as the original part.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All three substitute parts carry ROHS3 Compliant status and are REACH Unaffected, meeting current environmental and regulatory requirements.

Q: Does package compatibility require PCB layout changes?

A: No. All substitute parts use the 8-SOIC package with identical 5.30mm width. PCB footprints and layouts remain unchanged.

Q: What is the inventory status of these substitutes?

A: AT25SF321B-SHB-B has 986 units in stock, AT25FF321A-SHN-B has 934 units, and W25Q32JVSSIQ has 194,388 units available, providing multiple sourcing options.

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