Renesas AT25DN256-XMHF-B

Overview

AT25DN256-XMHF-B 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-XMHF-B datasheet, AT25DN256-XMHF-B pinout, AT25DN256-XMHF-B application, or AT25DN256-XMHF-B equivalent, key selection considerations include its flexible erase architecture (256-byte page / 4-KB / 32-KB blocks), 128-byte OTP security register with factory-unique ID, ultra-low deep power-down current (350nA typical), and industrial temperature range support.

Technical Context

The AT25DN256-XMHF-B implements a dedicated SPI interface with hardware-controlled write protection via the WP pin and suspend/resume capability via HOLD. Its memory array uses uniform block sizing-256-byte pages, 4-KB and 32-KB erase blocks, and full-chip erase-to minimize wasted space in mixed-code-and-data applications.

Dual-output read mode (opcode 3Bh) enables two bits per SCK falling edge using SI (I/O0) and SO (I/O1) as concurrent outputs, doubling effective data rate versus standard single-output reads. Internal status register polling (RDY/BUSY bit) supports efficient command completion detection without fixed timing waits.

Key Specifications

Pinout & Package

AT25DN256-XMHF-B is packaged in an 8-lead SOIC (150-mil) footprint, compatible with standard surface-mount assembly processes and legacy PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W25Q256JWEIQ and MX25L25635F, the AT25DN256-XMHF-B uniquely combines ultra-low power consumption, on-chip OTP security with factory-unique ID, and dual-output read - making it optimal for secure, battery-constrained edge devices requiring verified identity and minimal energy use.

Availability

AT25DN256-XMHF-B is available at Aetrix Electronics and suitable for IoT edge node firmware storage, industrial HMI code shadowing, medical wearable data logging, and automotive telematics boot memory requiring stable component supply across extended product lifecycles.

Supply support for AT25DN256-XMHF-B 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, non-volatile memory and analog interface solutions for resource-constrained embedded systems.

The AT25DN256 product line was designed specifically for mixed code-and-data storage in battery-powered and industrial applications where fine-grained erase control, security, and ultra-low power are critical.

FAQ

What is the maximum clock frequency supported by the AT25DN256-XMHF-B for read operations?

The AT25DN256-XMHF-B supports up to 104 MHz for standard Read Array (0Bh) and Dual-Output Read (3Bh) commands. At this frequency, the device achieves a clock-to-output delay (tV) of 6 ns, enabling high-speed data retrieval essential for fast-boot microcontrollers and real-time firmware execution. The 03h opcode supports lower-frequency reads up to 33 MHz.

Does the AT25DN256-XMHF-B include hardware write protection, and how is it implemented?

Yes, the AT25DN256-XMHF-B implements hardware write protection via the WP (Write Protect) pin, which is active-low and internally pulled high. When driven low, it locks protected memory sectors to prevent accidental or malicious program/erase operations. This feature works independently of software commands and remains effective even during power cycling, ensuring robust firmware integrity in mission-critical systems.

How does the dual-output read mode improve throughput in the AT25DN256-XMHF-B?

The AT25DN256-XMHF-B's dual-output read mode (enabled by opcode 3Bh) uses both SI (I/O0) and SO (I/O1) pins as concurrent data outputs, delivering two bits per SCK falling edge. This effectively doubles the data rate compared to standard single-output SPI reads at the same clock frequency - accelerating boot image loading, GUI asset streaming, and firmware updates without requiring interface redesign.

What erase block sizes are available on the AT25DN256-XMHF-B, and why does granularity matter?

The AT25DN256-XMHF-B supports four erase granularities: 256-byte page, 4-KB block, 32-KB block, and full-chip erase. Fine-grained 256-byte page erase minimizes wasted space when updating small firmware patches or configuration data, while larger blocks optimize bulk operations. This flexibility prevents memory fragmentation common in large-block-only Flash, improving usable density in mixed code/data applications.

Is the AT25DN256-XMHF-B suitable for industrial temperature environments?

Yes, the AT25DN256-XMHF-B is fully specified for the industrial temperature range of –40°C to +85°C. Its electrical parameters-including read timing, program/erase times, and power consumption-are guaranteed across this range, making it appropriate for deployment in factory automation HMIs, outdoor environmental sensors, and under-hood automotive modules where thermal stability is mandatory.