Renesas AT25DF256-SSHNGU-B

Overview

AT25DF256-SSHNGU-B from Renesas Electronics is a 256-Kbit serial Flash memory IC supporting SPI Modes 0 and 3, dual-output read at up to 50 MHz, 1.65 V–3.6 V single-supply operation, and flexible erase granularity (256-byte page, 4-kByte/32-kByte blocks). It serves as nonvolatile code storage and data logging in resource-constrained embedded systems.

For engineers reviewing the AT25DF256-SSHNGU-B datasheet, AT25DF256-SSHNGU-B pinout, AT25DF256-SSHNGU-B application, or AT25DF256-SSHNGU-B equivalent, key selection criteria include dual-read throughput, ultra-deep power-down current (200 nA), OTP security register programmability, hardware write protection via WP pin, and compatibility with industrial temperature range (−40 °C to +85 °C).

Technical Context

The AT25DF256-SSHNGU-B implements a dedicated SPI interface with four signal lines (CS, SCK, SI/I/O0, SO/I/O1) and supports dual-output read using both SI and SO as data outputs-enabling two bits per clock cycle. Its internal address counter auto-increments during sequential reads, eliminating host-side address management overhead.

Device operation relies on opcode-driven command execution (e.g., 02h for page program, 20h for 4-kByte block erase, 3Bh for dual-output read), with status register polling (05h) required to confirm completion of self-timed operations like erase or program. Protection is enforced via hardware (WP pin) and software (status register BPL bit), while the 128-byte OTP register includes factory-programmed unique ID and user-programmable fields.

Key Specifications

Pinout & Package

AT25DF256-SSHNGU-B is packaged in an 8-lead SOIC (150-mil) with standard JEDEC footprint. Pin functions are electrically defined and validated per Renesas DS-AT25DF256-035 Rev.G.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W25Q256JWEIQ and MX25L25635F, AT25DF256-SSHNGU-B uniquely balances 1.65 V operation, dual-output read efficiency, 200 nA ultra-deep power-down, and factory-programmed UID-making it optimal for battery-powered, security-aware, and voltage-flexible embedded systems.

Availability

AT25DF256-SSHNGU-B is available at Aetrix Electronics and suitable for industrial PLC firmware storage, medical sensor data logging, and automotive body control module applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for AT25DF256-SSHNGU-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

Renesas Electronics is a global semiconductor leader delivering microcontrollers, analog, power, and connectivity solutions for automotive, industrial, and IoT markets.

The AT25DF256 product line targets cost-optimized, low-voltage serial Flash applications in space-constrained embedded systems-emphasizing flexible erase architecture, ultra-low power states, and integrated security features for firmware and data integrity.

FAQ

What is the maximum clock frequency supported by AT25DF256-SSHNGU-B for dual-output read operations?

The AT25DF256-SSHNGU-B supports dual-output read (opcode 3Bh) at up to 50 MHz. This is lower than its 104 MHz maximum for standard commands (e.g., page program or block erase) due to timing constraints in dual-I/O mode. The 50 MHz limit ensures reliable 2-bit-per-cycle data transfer on both SI and SO pins while maintaining setup/hold margins across temperature and voltage ranges specified in the datasheet.

Does AT25DF256-SSHNGU-B support 4-byte addressing for memory expansion beyond 16 Mbit?

No, AT25DF256-SSHNGU-B does not support 4-byte addressing. Its memory array is limited to 256 Kbit (32 KByte), with address space spanning 000000h to 007FFFh (23-bit addressing). All opcodes require exactly three address bytes, and upper address bits (A23–A15) are ignored per the datasheet. This design reflects its role as a compact, low-density code/data storage device-not a scalable high-capacity Flash.

How is hardware write protection implemented on AT25DF256-SSHNGU-B?

Hardware write protection on AT25DF256-SSHNGU-B is implemented via the active-low WP pin, which-when asserted-locks protected memory sectors regardless of status register settings. The WP pin is internally pulled high and must be driven low externally to activate protection. It works in conjunction with the Block Protect (BPL) bit in the status register to define protected regions. This dual-layer mechanism prevents accidental writes during power transients or software faults.

What is the purpose of the 128-byte OTP security register in AT25DF256-SSHNGU-B?

The 128-byte OTP security register in AT25DF256-SSHNGU-B contains 64 bytes factory-programmed with a unique device identifier and 64 bytes user-programmable for secure data. It supports one-time-only writes per byte, making it suitable for electronic serial numbers (ESN), cryptographic key storage, or immutable device binding. Once programmed, OTP bytes cannot be erased or rewritten-ensuring tamper-resistant identity and credential storage independent of main memory.

Can AT25DF256-SSHNGU-B operate reliably at 1.65 V across its full temperature range?

AT25DF256-SSHNGU-B operates at 1.65 V minimum only within the temperature range of −10 °C to +85 °C. For extended industrial operation from −40 °C to +85 °C, the supply voltage must be ≥1.7 V per the datasheet's DC operating range table. This voltage–temperature derating ensures stable internal charge pump performance and reliable program/erase margin at cold extremes.