Renesas AT25DN256-SSHFGP-T

Overview

AT25DN256-SSHFGP-T from Adesto Technologies is a 256-Kbit serial flash memory IC with SPI interface, dual-output read capability, 104MHz max clock frequency, 6ns clock-to-output delay, and flexible erase architecture supporting 256-byte page, 4-Kbyte block, 32-Kbyte block, and full-chip erase - deployed in embedded code shadowing and mixed code/data storage applications.

For engineers reviewing the AT25DN256-SSHFGP-T datasheet, AT25DN256-SSHFGP-T pinout, AT25DN256-SSHFGP-T application, or AT25DN256-SSHFGP-T equivalent, key selection considerations include dual-output read throughput, hardware write protection via WP pin, 128-byte OTP security register (64B factory ID + 64B user-programmable), ultra-deep power-down current (350nA typical), and industrial temperature range compliance.

Technical Context

The AT25DN256-SSHFGP-T implements a standard SPI master-slave interface with support for Modes 0 and 3 (SCK polarity/phase variants), where data is latched on SCK rising edge and output on falling edge. It integrates an internal address counter for sequential reads and supports dual-output read using SI (I/O0) and SO (I/O1) pins to deliver two bits per clock cycle.

Its memory architecture features uniform 4-Kbyte and 32-Kbyte erase blocks plus 256-byte page erase, enabling efficient co-location of code modules and data segments without wasted space. The device includes dedicated logic for hardware write protection (WP pin), hold functionality (HOLD pin), and status register polling for busy detection during self-timed program/erase cycles.

Key Specifications

Pinout & Package

AT25DN256-SSHFGP-T uses an 8-lead SOIC (150-mil) package, RoHS-compliant and halogen-free. Pin functions are validated per DS-25DN256–039G–02/2022.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W25Q256JVSIM and MX25L25635FZC-10G, the AT25DN256-SSHFGP-T uniquely delivers 2.3V operation, 350nA ultra-deep power-down, and factory-programmed unique ID in a pin-compatible SOIC-8 footprint - making it optimal for secure, ultra-low-power embedded firmware storage.

Availability

AT25DN256-SSHFGP-T is available at Aetrix Electronics and suitable for industrial HMI, automotive infotainment boot memory, and secure IoT firmware storage requiring stable component supply across long-lifecycle programs.

Supply support for AT25DN256-SSHFGP-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 (acquired by Dialog Semiconductor, now part of Renesas Electronics) specialized in low-power, high-performance non-volatile memory and IoT connectivity solutions.

The AT25DN256 product line was designed for cost-sensitive, power-constrained embedded systems needing reliable code+data storage with hardware security and industrial temperature resilience.

FAQ

What is the maximum clock frequency supported by the AT25DN256-SSHFGP-T during read operations?

The AT25DN256-SSHFGP-T supports up to 104 MHz for Read Array (0Bh) and Page Program operations. For standard Read Array using opcode 03h, the maximum is 33 MHz. Dual-Output Read (3Bh) operates up to 50 MHz. These values are specified in the official datasheet DS-25DN256–039G–02/2022 and reflect actual timing margins under 2.3–3.6V supply and industrial temperature conditions. The AT25DN256-SSHFGP-T achieves this performance without requiring external voltage boosting.

Does the AT25DN256-SSHFGP-T support hardware write protection, and how is it implemented?

Yes, the AT25DN256-SSHFGP-T implements hardware write protection via the dedicated WP (Write Protect) pin, which is active-low and internally pulled high. When WP is driven low, it locks protected sectors regardless of software status register settings - providing fail-safe protection against accidental writes during power transients or firmware bugs. This feature is documented in Section 9.1 of the AT25DN256-SSHFGP-T datasheet and operates independently of the Write Enable Latch (WEL) bit.

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

The AT25DN256-SSHFGP-T includes a 128-byte One-Time Programmable (OTP) security register divided into two 64-byte sections: the first 64 bytes are factory-programmed with a unique device identifier, and the second 64 bytes are user-programmable once. This register supports secure device serialization, ESN storage, and locked key provisioning. Programming is performed using the 9Bh command and is irreversible - verified by the EPE bit in the status register if a write fails. This capability is explicitly defined in the AT25DN256-SSHFGP-T datasheet Section 6.

How does the dual-output read mode function on the AT25DN256-SSHFGP-T, and what pins are involved?

The AT25DN256-SSHFGP-T dual-output read mode uses both the SI (I/O0) and SO (I/O1) pins as simultaneous outputs during the 3Bh command sequence, delivering two bits per SCK falling edge - doubling effective throughput over standard SPI. SI transitions from input to output only during this mode; SO remains output throughout. The mode requires a dummy byte after the 3-byte address and is clocked at up to 50 MHz. This behavior is fully detailed in Section 7.2 of the AT25DN256-SSHFGP-T datasheet.

What erase block sizes are supported by the AT25DN256-SSHFGP-T, and why is this architecture beneficial?

The AT25DN256-SSHFGP-T supports four erase granularities: 256-byte page, 4-Kbyte block, 32-Kbyte block, and full-chip erase. This architecture minimizes wasted space when updating partial firmware or logging data - unlike legacy flash with only large-sector erase, it allows code modules and data segments to reside in isolated, optimally sized regions. As confirmed in Section 4 and Figure 4-1 of the AT25DN256-SSHFGP-T datasheet, this improves memory utilization efficiency by up to 40% in mixed code/data applications.