Renesas AT45DB021D-SSH-B

Overview

AT45DB021D-SSH-B from Adesto Technologies (now part of Dialog Semiconductor) is a 2-Mbit serial DataFlash memory IC with RapidS™ SPI-compatible interface, 256/264-byte page architecture, and integrated 256/264-byte SRAM buffer. It operates from a single 2.7V–3.6V supply, supports up to 66MHz clock frequency, and delivers 7mA typical active read current for embedded code shadowing and data logging applications.

For engineers reviewing the AT45DB021D-SSH-B datasheet, AT45DB021D-SSH-B pinout, AT45DB021D-SSH-B application, or AT45DB021D-SSH-B equivalent, key selection criteria include page-size configurability (256 vs. 264 bytes), flexible erase granularity (page/block/sector/chip), hardware/software write protection, and industrial temperature operation (–40°C to +85°C).

Technical Context

The AT45DB021D-SSH-B implements a dual-level memory architecture: 1,024 pages × 256/264 bytes of main Flash array plus one dedicated 256/264-byte SRAM buffer. Its RapidS™ interface supports SPI Modes 0 and 3 with up to 66MHz SCK, enabling high-speed continuous array reads without address retransmission across page boundaries.

All program and erase operations are self-timed and require no external high-voltage programming signals. The device integrates sector lockdown, a 128-byte security register (64-byte user-programmable + 64-byte unique ID), and JEDEC-standard manufacturer/device ID read capability for system identification and secure firmware storage.

Key Specifications

Pinout & Package

AT45DB021D-SSH-B is housed in an 8-pin SOIC package (3.9mm × 4.9mm, 1.27mm pitch) with standard lead finish and RoHS-compliant green packaging.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W25Q20EW and MX25L2006E, the AT45DB021D-SSH-B uniquely combines configurable page size, integrated SRAM buffer, and hardware-enforced sector lockdown - making it optimal for secure, low-overhead code shadowing and atomic data logging where deterministic timing and tamper resistance are critical.

Availability

AT45DB021D-SSH-B is available at Aetrix Electronics and suitable for firmware boot storage, secure configuration retention, industrial data logging, and audio voice playback applications requiring stable component supply and long-term lifecycle support.

Supply support for AT45DB021D-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 AT45DB021D-SSH-B belongs to the DataFlash® family, designed specifically for embedded systems needing SPI-based Flash with integrated buffer, flexible erase, and hardware security - targeting industrial control, medical devices, and intelligent sensors.

FAQ

What is the maximum clock frequency supported by the AT45DB021D-SSH-B for continuous array read operations?

The AT45DB021D-SSH-B supports up to 66 MHz for Continuous Array Read using opcodes 0BH (High Frequency Mode) and E8H (Legacy Command). This applies to both 256-byte and 264-byte page configurations and enables sustained data throughput ideal for code shadowing. The 03H Low Frequency Mode supports up to 33 MHz without dummy byte overhead. All timing complies with fCAR1/fCAR2 specifications in the official datasheet.

Does the AT45DB021D-SSH-B require external high-voltage programming signals?

No, the AT45DB021D-SSH-B does not require external high-voltage programming signals. It operates entirely from its single 2.7V–3.6V VCC supply for all read, program, and erase functions. All programming and erase cycles are internally self-timed, eliminating the need for charge pumps or auxiliary voltage rails - simplifying PCB design and improving system reliability.

How does page size configuration affect the AT45DB021D-SSH-B's addressing scheme?

Page size configuration directly determines the addressing format used by the AT45DB021D-SSH-B: in 256-byte mode, main memory uses 18-bit addressing (A17–A0) with A17–A8 as page address and A7–A0 as byte offset; in 264-byte mode, it uses 19-bit addressing (PA9–PA0 + BA8–BA0). Buffer addressing similarly shifts between BFA7–BFA0 (8-bit) and BFA8–BFA0 (9-bit), impacting firmware address calculation logic.

Can the AT45DB021D-SSH-B's SRAM buffer be accessed independently of main memory?

Yes, the AT45DB021D-SSH-B's 256/264-byte SRAM buffer can be accessed independently via dedicated opcodes D4H/D1H (buffer read) and 84H (buffer write). This allows simultaneous preparation of new data in the buffer while main memory is being read or erased - enabling pipelined operations critical for real-time data logging and firmware updates without interrupting host processor tasks.

What protection mechanisms prevent unauthorized modification of data stored in the AT45DB021D-SSH-B?

The AT45DB021D-SSH-B implements three-tiered protection: (1) hardware WP pin that globally disables program/erase when asserted low; (2) software-controlled Sector Protection Register for per-sector lock/unlock; and (3) Sector Lockdown command that permanently freezes protection status until power cycle. Additionally, the 128-byte Security Register includes 64-byte user space and 64-byte unique device ID to support cryptographic binding and secure boot verification.