Renesas AT25DF161-SSH-B

Overview

AT25DF161-SSH-B from Adesto Technologies (now part of Dialog Semiconductor) is a 16-Mbit serial SPI Flash memory IC designed for code shadowing and mixed code/data storage in embedded systems. It operates from a single 2.7V–3.6V supply, supports RapidS at 100 MHz, delivers ≤5 ns clock-to-output delay, and features uniform 4/32/64-Kbyte block erase plus full chip erase.

For engineers reviewing the AT25DF161-SSH-B datasheet, AT25DF161-SSH-B pinout, AT25DF161-SSH-B application, or AT25DF161-SSH-B equivalent, key selection considerations include sector lockdown capability, dual-input/dual-output programming/read modes, 100,000 program/erase cycles, 20-year data retention, and industrial temperature support (–40°C to +85°C).

Technical Context

The AT25DF161-SSH-B implements a flexible SPI interface supporting Modes 0 and 3 with configurable SCK polarity/phase, enabling interoperability with diverse host controllers. Its architecture integrates dual-input (SOI/SI) and dual-output (SO/SIO) modes for accelerated data transfer-doubling effective throughput during page program and array read operations.

Internally, it uses a segmented flash array divided into thirty-two 64-Kbyte sectors, each individually protectable via software commands or hardware WP pin control. Sector lockdown provides permanent read-only enforcement, while a 128-byte OTP security register enables device serialization and secure key storage.

Key Specifications

Pinout & Package

AT25DF161-SSH-B is packaged in an 8-lead SOIC (208-mil wide), with pins arranged in standard dual-inline format. All signals conform to SPI protocol timing and voltage levels for direct interfacing with ARM Cortex-M, RISC-V, and legacy MCU families.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W25Q16JVSSIQ and MT25QL128ABA8ESF-0SIT, the AT25DF161-SSH-B uniquely combines RapidS acceleration, hardware-enforced sector lockdown, and dedicated OTP security space - making it optimal for applications requiring deterministic, tamper-proof firmware partitioning at 16 Mbit density.

Availability

AT25DF161-SSH-B is available at Aetrix Electronics and suitable for industrial HMI displays, automotive telematics modules, medical infusion pumps, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for AT25DF161-SSH-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, acquired by Dialog Semiconductor in 2020, specialized in low-power, high-reliability nonvolatile memory and IoT connectivity solutions.

The AT25DF161 belongs to Adesto's DataFlash family - engineered for embedded systems demanding fast, secure, and granular code/data storage with minimal power and board space overhead.

FAQ

What is the maximum clock frequency supported by AT25DF161-SSH-B in RapidS mode?

The AT25DF161-SSH-B supports up to 100 MHz in RapidS mode, enabling high-speed sequential reads with a maximum clock-to-output delay (tV) of 5 ns. This allows efficient code shadowing into RAM for real-time execution in microcontroller-based systems. The AT25DF161-SSH-B maintains full functionality-including dual-output read-at this frequency, distinguishing it from standard SPI Flash devices limited to 85 MHz or lower.

Does AT25DF161-SSH-B require a separate programming voltage (VPP)?

No, the AT25DF161-SSH-B performs all program and erase operations using only the main VCC supply (2.7 V to 3.6 V); no external VPP or charge pump voltage is needed. This simplifies power design and eliminates associated components like voltage regulators or capacitors. The AT25DF161-SSH-B achieves this through on-chip charge pump circuitry integrated into its flash core, ensuring robust operation across the full supply range.

How does sector lockdown work on AT25DF161-SSH-B, and is it reversible?

Sector lockdown on the AT25DF161-SSH-B permanently disables program and erase operations for any selected 64-Kbyte sector using the 33h command; once locked, a sector cannot be unlocked or modified. This irreversible hardware feature protects critical firmware or security keys from malicious or accidental overwrite. The AT25DF161-SSH-B implements this via fuse-like circuitry within each sector's control logic, independent of software status registers.

Can AT25DF161-SSH-B operate in standard SPI Mode 0 and Mode 3 only - are other modes supported?

Yes, the AT25DF161-SSH-B explicitly supports only SPI Modes 0 and 3, as defined by SCK polarity and phase relationships. In both modes, data is latched on the rising edge of SCK and output on the falling edge. The AT25DF161-SSH-B does not support Modes 1 or 2; attempting to use them will result in undefined behavior or communication failure. This limitation ensures timing predictability and compatibility with widely deployed SPI controllers.

What is the purpose and size of the OTP security register in AT25DF161-SSH-B?

The AT25DF161-SSH-B includes a 128-byte One-Time Programmable (OTP) security register used for storing immutable data such as unique device identifiers, electronic serial numbers (ESNs), or cryptographic keys. Once programmed, bits cannot be reset or rewritten. This register resides outside the main flash array and is accessed via dedicated 9Bh (program) and 77h (read) commands. The AT25DF161-SSH-B leverages this space to enforce hardware-rooted device identity and secure boot chain integrity.