Renesas AT25DN256-MAHF-T

Overview

AT25DN256-MAHF-T from Adesto Technologies is a 256-Kbit serial SPI Flash memory IC optimized for code shadowing and mixed code/data storage in embedded systems. 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 dual-output read for enhanced throughput.

For engineers reviewing the AT25DN256-MAHF-T datasheet, AT25DN256-MAHF-T pinout, AT25DN256-MAHF-T application, or AT25DN256-MAHF-T equivalent, key selection considerations include its flexible erase architecture (256-byte page, 4/32-Kbyte blocks), hardware write protection via WP pin, 128-byte OTP security register with factory-unique ID, ultra-low deep power-down current (350nA), and industrial temperature range support.

Technical Context

The AT25DN256-MAHF-T implements a dedicated SPI interface with four signal lines (CS, SCK, SI/I/O0, SO/I/O1) and supports both standard and dual-output read modes. Its command set includes opcodes for Read Array (03h/0Bh), Dual Output Read (3Bh), Page Program (02h), Page Erase (81h), 4-Kbyte Block Erase (20h), 32-Kbyte Block Erase (52h/D8h), and Chip Erase (60h/C7h).

Internally, it uses an addressable 256-Kbit memory array (000000h–007FFFh) with automatic address wraparound, intelligent program/erase error detection (EPE bit), and status register polling for busy-state management. The device integrates hardware-controlled sector locking via the WP pin and a dedicated HOLD pin for communication suspension without reset.

Key Specifications

Pinout & Package

AT25DN256-MAHF-T is packaged in an 8-lead SOIC (150-mil) with industry-standard footprint and solder-reflow compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W25Q256JWEIQ and MX25L25635FZC-10G, the AT25DN256-MAHF-T uniquely combines ultra-low deep-power current (350 nA), dual-output read capability, and factory-programmed unique ID in OTP - making it optimal for secure, battery-sensitive edge devices where both longevity and authenticated identity matter.

Availability

AT25DN256-MAHF-T is available at Aetrix Electronics and suitable for wireless sensor nodes, industrial HMIs, automotive infotainment systems, medical diagnostics, and smart metering applications requiring stable component supply across extended product lifecycles.

Supply support for AT25DN256-MAHF-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

Adesto Technologies (now part of Dialog Semiconductor, part of Renesas Electronics) specialized in low-power, high-reliability non-volatile memory and analog ICs for IoT and industrial markets.

The AT25DN256 product line was designed specifically for mixed code-and-data storage in resource-constrained embedded systems, emphasizing ultra-low power, flexible erase granularity, and integrated security features like OTP serialization.

FAQ

What is the maximum operating frequency supported by the AT25DN256-MAHF-T?

The AT25DN256-MAHF-T supports a maximum clock frequency of 104 MHz for most commands including Read Array, Page Program, and Block Erase. Dual-Output Read operates up to 50 MHz, while legacy Read Array (03h opcode) is rated to 33 MHz. These values are specified under recommended operating conditions and must be validated against PCB layout and signal integrity in the target system. The AT25DN256-MAHF-T datasheet confirms these limits in Table 6-1 and Section 7.1.

Does the AT25DN256-MAHF-T support hardware write protection?

Yes, the AT25DN256-MAHF-T provides hardware-controlled write protection via the WP (Write Protect) pin. When asserted low, it locks protected memory sectors independently of software commands, preventing accidental or malicious overwrites during power transitions or firmware glitches. The WP pin is internally pulled-high and may be left floating if unused, though external connection to VCC is recommended for noise immunity. This feature is documented in Section 9.3 and Table 2-1 of the AT25DN256-MAHF-T datasheet.

What package type is used for the AT25DN256-MAHF-T?

The AT25DN256-MAHF-T uses an 8-lead SOIC (150-mil) package, as indicated by the "MAHF-T" suffix per Adesto's naming convention. This package is RoHS-compliant, green, and compatible with standard surface-mount reflow profiles. Pinout matches JEDEC MS-012, with CS, SO, WP, GND, VCC, HOLD, SCK, and SI arranged in standard order. Mechanical drawings and land patterns are provided in Figures 2-1 and 4-1 of the AT25DN256-MAHF-T datasheet.

How does the dual-output read mode function on the AT25DN256-MAHF-T?

The AT25DN256-MAHF-T implements Dual-Output Read using both SI (as I/O0) and SO (as I/O1) pins to output two bits per SCK falling edge, doubling effective read throughput versus standard SPI. It requires opcode 3Bh, three address bytes, and one dummy byte. Data MSB appears on SO, next bit on SI, continuing sequentially across four cycles per byte. This mode is validated up to 50 MHz and detailed in Section 7.2 and Figure 7-3 of the AT25DN256-MAHF-T datasheet.

What is the purpose and structure of the OTP security register in the AT25DN256-MAHF-T?

The AT25DN256-MAHF-T includes a 128-byte One-Time Programmable (OTP) Security Register: 64 bytes are factory-programmed with a unique device identifier (e.g., for ESN or cryptographic key binding), and 64 bytes are user-programmable for secure storage of keys or certificates. Once programmed, OTP bits cannot be altered. Access uses opcodes 9Bh (program) and 77h (read). This feature supports secure boot, device authentication, and regulatory traceability - fully specified in Sections 2 and 6 of the AT25DN256-MAHF-T datasheet.