Renesas AT45DB021D-SSH-T

Overview

AT45DB021D-SSH-T 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 single 2.7V–3.6V supply. It delivers up to 66 MHz read speed, supports continuous array read for code shadowing, and integrates one 256/264-byte SRAM buffer for efficient read-modify-write operations in embedded firmware storage.

For engineers reviewing the AT45DB021D-SSH-T datasheet, AT45DB021D-SSH-T pinout, AT45DB021D-SSH-T application, or AT45DB021D-SSH-T equivalent, key selection criteria include its dual-page-size flexibility (256 vs. 264 bytes), sector-level hardware/software write protection, 100,000 program/erase cycles, 20-year data retention, and industrial temperature support - all critical for reliable firmware, voice, and configuration storage in resource-constrained systems.

Technical Context

The AT45DB021D-SSH-T implements a serial flash architecture with separate main memory (1,024 pages × 256/264 bytes) and dedicated 256/264-byte SRAM buffer, enabling true EEPROM emulation via self-contained read-modify-write sequences. Its RapidS interface supports SPI Modes 0 and 3 at up to 66 MHz, with three distinct read commands (03H, 0BH, E8H) optimized for low-frequency, high-frequency, and legacy compatibility.

Memory organization uses hierarchical granularity: 8 sectors (0a–7), each containing multiple 2-Kbyte blocks (8 pages each), allowing precise erase control - page (256 B), block (2 KB), sector (32 KB), or chip (2 Mbit). All program and erase operations are fully self-timed, with status register polling supported, and hardware write protection via WP pin operates independently of software sector lockdown.

Key Specifications

Pinout & Package

AT45DB021D-SSH-T is housed in an 8-pin SOIC package (3.9 mm × 4.9 mm) with standard lead pitch. Pin functions are electrically defined and validated per Adesto datasheet 3638L–DFLASH–1/2013.

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-T uniquely combines SRAM buffer-assisted EEPROM emulation, dual page-size flexibility, and continuous array read - making it optimal for firmware update resilience and deterministic code shadowing where minimal host intervention is critical.

Availability

AT45DB021D-SSH-T is available at Aetrix Electronics and suitable for firmware storage, configuration data logging, and voice/data buffering applications requiring stable component supply, industrial temperature operation, and long-term lifecycle support.

Supply support for AT45DB021D-SSH-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 in 2020, specialized in low-power, high-reliability nonvolatile memory solutions for industrial and IoT applications.

The AT45DB021D-SSH-T belongs to the DataFlash® family, designed specifically for systems needing SPI-based flash with integrated SRAM buffer and EEPROM-like update semantics - targeting embedded firmware, voice, and secure configuration storage.

FAQ

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

The AT45DB021D-SSH-T supports up to 66 MHz for Continuous Array Read using opcodes 0BH (High Frequency Mode) and E8H (Legacy Command), as specified by the fCAR1 parameter. This enables sustained data throughput of 8.25 MB/s, ideal for code shadowing and real-time audio streaming. The 03H Low Frequency Mode supports up to 33 MHz without dummy bytes. All timing values are validated across the full industrial temperature range.

Does the AT45DB021D-SSH-T support true byte-alterable EEPROM emulation?

Yes, the AT45DB021D-SSH-T enables true EEPROM emulation through its dedicated 256/264-byte SRAM buffer and self-contained read-modify-write sequence. Host firmware loads data into the buffer, modifies specific bytes, then executes a buffer-to-page program command - all without external RAM or complex wear-leveling algorithms. This capability is intrinsic to the AT45DB021D-SSH-T architecture and requires no additional hardware.

How does hardware write protection work on the AT45DB021D-SSH-T?

Hardware write protection on the AT45DB021D-SSH-T is implemented via the WP (Write Protect) pin: when pulled low, it globally disables program and erase operations on sectors marked in the Sector Protection Register - independent of software commands. The WP pin is internally pulled high, so leaving it unconnected defaults to unprotected mode. This feature ensures fail-safe protection even if firmware is compromised, and is fully documented for the AT45DB021D-SSH-T in datasheet section 1.1.

What page sizes are supported by the AT45DB021D-SSH-T, and how is the selection made?

The AT45DB021D-SSH-T supports both 256-byte and 264-byte page sizes. The 256-byte "power-of-two" format simplifies address alignment for MCU instruction fetch; the 264-byte format reserves 8 bytes for metadata or ECC. Page size is factory-configured at wafer sort and cannot be changed in-circuit - the AT45DB021D-SSH-T variant shipped by Aetrix is pre-configured for 256-byte pages, as confirmed by Adesto's official ordering information and datasheet Table 1-2.

Is the AT45DB021D-SSH-T RoHS compliant and halogen-free?

Yes, the AT45DB021D-SSH-T is RoHS compliant, Pb-free, and halogen-free, meeting JEDEC J-STD-609 Category 1 requirements. The "-SSH-T" suffix explicitly denotes Green (Pb/Halide-free/RoHS Compliant) packaging per Adesto's packaging nomenclature. This compliance is verified in the device's material declaration and applies to both SOIC and UDFN variants of the AT45DB021D family.