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-SSH-B is a functional replacement candidate for the AT25DF081A-SSH-T within the same SPI serial flash family, sharing an identical 8-SOIC package and supply voltage range, but the halved 4 Mbit density and reduced clock frequency require validation against the target application's memory capacity and timing budget before substitution.
Package Type
High match
Supply Voltage Range
High match
Memory Density
Not compatible
Maximum Clock Frequency
Validation required
Parts at a glance
Part B
AT25DF041A-SSH-B
Adesto Technologies
- Lifecycle
- Active
- Stock
- 6689 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-SSH-B | Why it matters |
|---|---|---|---|
| Memory Density | 8 Mbit (1 MB) | 4 Mbit (512 KB) | Density determines total storage capacity; a smaller device cannot hold firmware or data sized for the larger part, so this is the primary substitutability constraint. |
| Memory Organization | 1,024 pages x 256 bytes; 256 sectors x 4 KB | 512 pages x 256 bytes; 128 sectors x 4 KB | Page and sector geometry affects erase granularity and driver addressing; matching 256-byte pages and 4 KB sectors keeps low-level software compatible. |
| Supply Voltage Range | 2.7 V to 3.6 V | 2.7 V to 3.6 V | Identical operating voltage means the same power rail and level-shifting design can be reused without circuit changes. |
| Interface Type | SPI (single/dual output), up to 100 MHz | SPI (single/dual output), up to 100 MHz | A matching SPI interface and clock rate ensures the same host controller and firmware command set can drive either device. |
| Package | 8-lead SOIC (150 mil) | 8-lead SOIC (150 mil) | Same package and pinout allow a drop-in board replacement without PCB redesign. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent temperature ratings confirm both parts suit the same industrial-grade environmental conditions. |
| Maximum Clock Frequency | 100 MHz | 70 MHz | A lower maximum clock on the smaller device may require reducing SPI bus speed, affecting read/write throughput in timing-sensitive designs. |
| Typical Page Program Time | 1.0 ms typical | 1.5 ms typical | Program time influences firmware update and data-logging throughput; slower programming may affect real-time write budgets. |
| Sector Erase Time | 50 ms typical (4 KB sector) | 60 ms typical (4 KB sector) | Erase timing affects block-update latency; differing values may require timing margin adjustments in erase-then-write routines. |
| Active Read Current | 7 mA typical at 100 MHz | 5 mA typical at 70 MHz | Current draw impacts power budget and thermal design, especially in battery-powered or densely packed systems. |
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-SSH-B |
|---|---|---|
| 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 | 70 MHz |
| Write Cycle Time - Word Page | 7µs, 3ms | 7µs, 5ms |
| Voltage - Supply | 2.7V ~ 3.6V | 2.7V ~ 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-SSH-B?
The primary difference is memory density: the AT25DF081A-SSH-T is an 8-Mbit (1 MByte) SPI serial flash device, while the AT25DF041A-SSH-B is a 4-Mbit (512 KByte) device. Both are part of the Adesto (formerly Atmel) AT25DF series, use the same SPI interface, and are offered in an 8-lead SOIC package (SSH suffix), but they differ in total storage capacity and therefore in page/block organization and device ID values.
Are the AT25DF081A-SSH-T and AT25DF041A-SSH-B pin-compatible?
Yes. Both devices use the standard 8-lead SOIC (0.150" body) pinout for SPI serial flash: CS, SO, WP, GND, SI, SCLK, HOLD, and VCC. Because the pin functions and package footprint are the same, they are pin-compatible in the same 8-SOIC land pattern, though firmware must account for the different densities and device IDs.
Do both devices support the same SPI interface and operating voltage?
Yes. Both the AT25DF081A-SSH-T and AT25DF041A-SSH-B support the standard 4-wire SPI interface (Mode 0 and Mode 3) and operate from a single 2.7 V to 3.6 V supply, making them suitable for 3.3 V systems. Both also support Dual-Output Read and Dual-I/O Read modes for higher throughput.
Can the AT25DF041A-SSH-B be used as a drop-in replacement for the AT25DF081A-SSH-T?
Not as a direct drop-in replacement. Although they are pin-compatible and share the same command set, the AT25DF041A-SSH-B has half the density (4 Mbit vs 8 Mbit). Firmware that addresses the upper 4 Mbit of the AT25DF081A will fail on the AT25DF041A, and the JEDEC device ID differs. The design must be validated against the smaller density and updated device ID before substitution.
What are the page size and sector/block erase organization of these devices?
Both devices use a 256-byte page size. The AT25DF081A-SSH-T (8 Mbit) is organized with 4-KByte sectors and 64-KByte blocks, while the AT25DF041A-SSH-B (4 Mbit) uses the same 4-KByte sector and 64-KByte block granularity but with fewer total sectors and blocks due to its lower density. Both support page program, sector erase, block erase, and chip erase operations.
Do both parts support the same clock frequency and read throughput?
Both devices support a maximum SPI clock frequency of 85 MHz for standard read operations, and both offer Dual-Output and Dual-I/O read modes that effectively double data throughput. Because the command set and interface timing are shared across the AT25DF series, the achievable read throughput is comparable, with the main difference being total addressable memory.
What is the difference in JEDEC device ID between the two parts?
The JEDEC ID (manufacturer and device ID read via the Read JEDEC ID command, 0x9F) differs because the density code differs. The AT25DF081A-SSH-T reports an 8-Mbit density code, while the AT25DF041A-SSH-B reports a 4-Mbit density code. Firmware that hard-codes or validates the device ID must be updated when switching between the two parts.
Are both devices specified over the same temperature range and package?
Yes. Both the AT25DF081A-SSH-T and AT25DF041A-SSH-B are offered in the 8-lead SOIC package (SSH suffix) and are specified for the industrial temperature range of -40°C to +85°C, making them suitable for the same industrial and embedded applications.