Renesas AT25SF081-MHF-T

Overview

AT25SF081-MHF-T from Dialog Semiconductor (acquired Adesto) is an 8-Mbit SPI serial flash memory IC designed for code shadowing and data storage in consumer electronics. It operates from 2.3V–3.6V, supports SPI Modes 0/3, delivers 104MHz max clock frequency, achieves 6ns clock-to-output delay, and features uniform 4/32/64-Kbyte block erase plus full chip erase.

For engineers reviewing the AT25SF081-MHF-T datasheet, AT25SF081-MHF-T pinout, AT25SF081-MHF-T application, or AT25SF081-MHF-T equivalent, key selection considerations include dual/quad I/O read throughput, hardware write protection via WP pin, security register pages for ESN serialization, deep power-down current (2µA), and industrial temperature range compliance.

Technical Context

The AT25SF081-MHF-T implements a flexible multi-granularity erase architecture with uniform 4-Kbyte, 32-Kbyte, 64-Kbyte, and full-chip erase blocks-optimized to minimize wasted space in mixed code-and-data applications. Its memory array is organized to allow independent placement of code modules and data segments in dedicated erase regions.

It supports four SPI read modes: standard single-I/O (03h/0Bh), dual-output (3Bh), dual-I/O (BBh), and quad-I/O (EBh), all requiring QE bit enablement for quad variants. The device uses SI/SO/WP/HOLD as bidirectional I/O pins (I/O0–I/O3) during high-speed read operations, while retaining standard SPI functionality in legacy mode.

Key Specifications

Pinout & Package

AT25SF081-MHF-T is packaged in an 8-lead SOIC (208-mil) with industry-standard pinout and RoHS-compliant green finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial flash memory applications.

Compared with W25Q80DVSSIG and MT25QL80ABB8E12-0SIT, AT25SF081-MHF-T uniquely provides three individually lockable security register pages and hardware WP-pin protection-making it the only option among the three qualified for ESN serialization and tamper-resistant key storage in cost-sensitive consumer and industrial designs.

Availability

AT25SF081-MHF-T is available at Aetrix Electronics and suitable for smart home hubs, industrial PLCs, and automotive infotainment systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AT25SF081-MHF-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Dialog Semiconductor acquired Adesto Technologies in 2021 and now offers its portfolio of low-power, high-performance memory solutions-including serial flash, conductive polymer tantalum capacitors, and energy harvesting PMICs.

The AT25SF081 product line was originally developed by Adesto for ultra-low-power, secure code-and-data storage in battery-operated and industrial edge devices-emphasizing erase efficiency, security, and extended data retention.

FAQ

What is the maximum operating frequency supported by the AT25SF081-MHF-T?

The AT25SF081-MHF-T supports a maximum clock frequency of 104 MHz for quad-I/O and dual-I/O read operations, and up to 85 MHz for standard and dual-output read modes. This enables peak data rates of 52 MB/s in quad-I/O mode. The device maintains timing integrity across the full industrial temperature range (−40°C to +85°C), and the 6 ns clock-to-output delay ensures tight timing margins for high-speed host interfaces. All timing specifications are guaranteed per the official DS-25SF081–045K–06/2023 datasheet.

Does the AT25SF081-MHF-T support hardware write protection?

Yes, the AT25SF081-MHF-T includes hardware-controlled write protection via the WP pin. When asserted low, the WP pin locks designated memory blocks against program and erase operations-providing physical-level security independent of software state. The device also supports software-controlled protection through status register bits, but the WP pin offers fail-safe, always-active blocking. This dual-layer protection is especially valuable in safety-critical or field-upgradeable systems where accidental or malicious writes must be prevented. The WP pin is internally pulled-high and may be left floating if unused.

How many security register pages does the AT25SF081-MHF-T provide, and what are their use cases?

The AT25SF081-MHF-T provides three dedicated, programmable security register pages-each individually lockable to prevent further writes. These pages are commonly used for unique device serialization, Electronic Serial Number (ESN) storage, locked cryptographic key material, or factory calibration data. Unlike general-purpose memory, security registers are mapped outside the main array and accessed via dedicated opcodes (42h/44h/48h). Their hardware lock capability ensures that once programmed and locked, contents remain immutable-even after power cycles or reset events-making them ideal for root-of-trust implementations in AT25SF081-MHF-T–based systems.

What erase block sizes are available on the AT25SF081-MHF-T?

The AT25SF081-MHF-T supports uniform 4-Kbyte, 32-Kbyte, and 64-Kbyte block erase operations, plus full chip erase. This multi-granularity architecture eliminates wasted space common with fixed large-block flash-enabling efficient allocation of code modules and data segments into separate, independently erasable regions. For example, a 4-Kbyte block can hold a single firmware update patch without affecting adjacent bootloader or configuration sectors. Typical erase times are 70 ms (4-Kbyte), 300 ms (32-Kbyte), and 600 ms (64-Kbyte), all specified at VCC = 3.0V and TA = 25°C per the AT25SF081-MHF-T datasheet.

Is the AT25SF081-MHF-T pin-compatible with the newer AT25SF081B variant?

No, the AT25SF081-MHF-T is not pin-compatible with the AT25SF081B. While both share the same 8-Mbit density and SOIC-8 package footprint, the AT25SF081B introduces revised timing parameters, enhanced reliability features, and updated command set behavior-including changes to continuous read mode and security register handling. Dialog explicitly marks AT25SF081-MHF-T as "Not recommended for new designs" and advises migration to AT25SF081B. Direct replacement requires validation of timing margins, firmware command sequencing, and security register initialization routines. Always consult the latest AT25SF081B datasheet before redesign.