Part A
AT25DF081A-SSH-T
Adesto Technologies
- Lifecycle
- Active
- Stock
- 3274 PCS
- Package
- SOIC-8
- Series
- Memory
Replacement verdict
Compatible functional replacement candidate
The AT25DF041A-SSHF-T is a functional replacement candidate for the AT25DF081A-SSH-T, sharing the same SPI serial flash interface, SOIC-8 package, and supply voltage range, though the halved density and differing temperature grade require validation against the target application's memory capacity and environmental requirements.
Memory Density
Not compatible
Package Type
High match
Supply Voltage Range
High match
Operating Temperature Range
Validation required
Parts at a glance
Part B
AT25DF041A-SSHF-T
Adesto Technologies
- Lifecycle
- Active
- Stock
- 9021 PCS
- Package
- SOIC-8
- Series
- Memory
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AT25DF081A-SSH-T | AT25DF041A-SSHF-T | Why it matters |
|---|---|---|---|
| Memory Density | 8 Mbit (1 MB) | 4 Mbit (512 KB) | Density determines total storage capacity; a 4 Mbit device cannot hold firmware or data images sized for an 8 Mbit device, so they are not drop-in substitutes. |
| Memory Organization | 1,024 pages x 256 bytes | 512 pages x 256 bytes | Page size affects write buffering and programming routines; identical 256-byte pages allow the same page-write driver logic to be reused. |
| Interface Type | SPI (Single/Dual) Serial | SPI (Single/Dual) Serial | A matching SPI interface ensures the same host controller pins and command protocol can be used without redesign. |
| Supply Voltage Range | 2.7 V to 3.6 V | 2.7 V to 3.6 V | Identical operating voltage windows mean the same power rail and level-shifting considerations apply to both parts. |
| Maximum Clock Frequency | 100 MHz | 100 MHz | Matching clock rates ensure comparable read/write throughput and timing budget compatibility with the host SPI bus. |
| Package / Mounting | 8-SOIC, Surface Mount | 8-SOIC, Surface Mount | The same package and footprint allow either device to be placed on the same PCB land pattern without layout changes. |
| Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C (industrial) | Operating temperature range must cover the application environment; both parts support industrial-grade conditions, though suffix coding differs. |
| Part Status / Lifecycle | Not recommended for new designs (NRND) | Not recommended for new designs (NRND) | Lifecycle status affects long-term availability and sourcing risk; both being NRND signals designers should plan for replacement parts. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AT25DF081A-SSH-T | AT25DF041A-SSHF-T |
|---|---|---|
| Supplier | - | Dialog Semiconductor GmbH |
| Part Status | Active | Obsolete |
| Memory Type | Non-Volatile | Non-Volatile |
| Memory Format | FLASH | FLASH |
| Technology | FLASH | FLASH |
| Memory Size | 8Mb (256 Bytes x 4096 pages) | 4Mb (512K x 8) |
| Memory Interface | SPI | SPI |
| Clock Frequency | 100 MHz | 50 MHz |
| Write Cycle Time - Word Page | 7µs, 3ms | 7µs, 5ms |
| Voltage - Supply | 2.7V ~ 3.6V | 2.3V ~ 3.6V |
| Operating Temperature | -40°C ~ 85°C (TC) | -40°C ~ 85°C (TC) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the AT25DF081A-SSH-T and AT25DF041A-SSHF-T?
The primary difference is memory density: the AT25DF081A-SSH-T is an 8-Mbit (1 MByte) SPI serial flash device, while the AT25DF041A-SSHF-T is a 4-Mbit (512 KByte) device. Both are part of the Adesto (formerly Atmel) AT25DF series of SPI serial flash memories and share the same command set and interface family, but they differ in capacity and therefore in page/block organization and total addressable space.
Are the AT25DF081A-SSH-T and AT25DF041A-SSHF-T pin-compatible?
Both devices are offered in the same 8-lead SOIC (0.150" body) package with a standard SPI pinout (CS, SCK, SI, SO, WP, HOLD, VCC, GND). Because they share the same package and pin assignment, they are pin-compatible at the package level; however, the difference in density means the firmware must address the correct memory size and the design must account for the different block protection and address ranges.
Can the AT25DF041A-SSHF-T be used as a drop-in replacement for the AT25DF081A-SSH-T?
Not as a direct drop-in replacement. Although the package and pinout are compatible, the AT25DF041A-SSHF-T has only half the density (4 Mbit vs 8 Mbit). A design requiring 8 Mbit of storage cannot be satisfied by the 4-Mbit device, and firmware that addresses the full 8-Mbit range would access non-existent addresses. Replacement is only valid if the application's actual storage requirement fits within 4 Mbit and the firmware is adjusted accordingly.
What is the supply voltage and operating temperature range for these devices?
Both the AT25DF081A-SSH-T and AT25DF041A-SSHF-T operate from a single 2.7 V to 3.6 V supply and are specified for the industrial temperature range of -40°C to +85°C, consistent with the AT25DF series datasheet specifications. Designers should confirm the exact ordering-code suffix against the manufacturer datasheet for the specific grade.
Do both devices support the same SPI modes and clock frequencies?
Yes. Both devices support SPI modes 0 and 3 and are specified for clock frequencies up to 66 MHz for fast read operations, consistent with the AT25DF series. They share the same instruction set, including standard read, fast read, page program, sector erase, block erase, and chip erase commands, so firmware command sequences are largely transferable between the two densities.
How do the erase block architectures of the two devices compare?
Both devices use a uniform 4-KByte sector erase granularity along with larger block erase options (typically 32-KByte and 64-KByte blocks) and full-chip erase, following the AT25DF series architecture. The difference is the total number of sectors/blocks available: the 8-Mbit AT25DF081A-SSH-T provides twice as many 4-KByte sectors as the 4-Mbit AT25DF041A-SSHF-T. Firmware should reference the specific datasheet for exact sector and block counts.
Which device should be selected for a new design?
Selection depends on storage requirements. Choose the AT25DF081A-SSH-T when the application needs up to 8 Mbit of non-volatile SPI flash storage, and the AT25DF041A-SSHF-T when 4 Mbit is sufficient. Because both share the same package, pinout, voltage range, and command set, a design can be laid out to accommodate either density, allowing cost optimization by populating the smaller device where firmware and data fit within 4 Mbit.