Renesas AT45DB021D-SH-B

Overview

AT45DB021D-SH-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 single 2.7–3.6V supply. It delivers up to 66 MHz read throughput, 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 applications.

For engineers reviewing the AT45DB021D-SH-B datasheet, AT45DB021D-SH-B pinout, AT45DB021D-SH-B application, or AT45DB021D-SH-B equivalent, key selection criteria include page-size configurability (256 vs. 264 bytes), sector-level hardware/software write protection, industrial temperature support (−40°C to +85°C), and Deep Power-down current (15 μA typical).

Technical Context

The AT45DB021D-SH-B implements a dual-layer 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 66 MHz clock frequency, enabling high-speed sequential access without address lines or parallel bus overhead.

All program and erase operations-including Page (256 B), Block (2 KB), Sector (32 KB), and Chip (2 Mbit)-are self-timed and require no external high-voltage programming. The device uses JEDEC-standard Manufacturer and Device ID read, includes a 128-byte security register (64-byte user programmable + 64-byte unique ID), and supports individual sector lockdown for secure code/data storage.

Key Specifications

Pinout & Package

AT45DB021D-SH-B is housed in an 8-pin SOIC package (3.9 mm × 4.9 mm, 1.27 mm pitch) with standard lead finish. Pin functions are fully defined for SPI-based host interfacing and hardware write protection.

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-SH-B uniquely combines SRAM buffer-assisted EEPROM emulation, factory-configurable page size, and hardware-enforced sector lockdown-making it optimal for secure, low-power, field-upgradable embedded systems requiring robust data integrity.

Availability

AT45DB021D-SH-B is available at Aetrix Electronics and suitable for firmware storage, secure bootloader implementation, industrial data logging, and HMI configuration management requiring stable component supply and long-term lifecycle support.

Supply support for AT45DB021D-SH-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 ultra-low-power, high-reliability nonvolatile memory and analog ICs for IoT and industrial applications.

The AT45DB021D-SH-B belongs to the DataFlash® family, designed specifically for embedded systems needing SPI-based Flash with integrated buffer, flexible erase, and hardware security - targeting code shadowing, secure boot, and parameter storage where pin count and power efficiency are critical.

FAQ

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

The AT45DB021D-SH-B supports continuous array read at up to 66 MHz using the RapidS™ interface with opcodes E8H (legacy) or 0BH (high-frequency mode). This performance is achievable in both 256-byte and 264-byte page configurations and bypasses the SRAM buffer to deliver raw Flash throughput - making the AT45DB021D-SH-B suitable for real-time code shadowing in microcontroller-based systems.

Does the AT45DB021D-SH-B require external high-voltage programming?

No, the AT45DB021D-SH-B operates entirely from a single 2.7–3.6 V supply for all operations - including program and erase - with no external high-voltage circuitry needed. All programming and erase cycles are self-timed internally, and the AT45DB021D-SH-B automatically manages voltage thresholds and timing, simplifying system design and reducing bill-of-materials cost.

How does the SRAM buffer in the AT45DB021D-SH-B improve data reliability?

The AT45DB021D-SH-B includes a dedicated 256/264-byte SRAM buffer that enables atomic read-modify-write operations without external memory. When updating a byte or word in Flash, the host reads the full page into the buffer, modifies the target location, then writes the entire page back - preventing partial writes or corruption during power loss. This capability makes the AT45DB021D-SH-B ideal for storing critical configuration data or runtime parameters.

Can the AT45DB021D-SH-B be used in industrial temperature environments?

Yes, the AT45DB021D-SH-B is rated for operation from −40°C to +85°C and is qualified for industrial applications. Its low active current (7 mA typical), 15 μA Deep Power-down mode, and robust erase/write endurance (100,000 cycles) ensure reliable performance in extended-temperature deployments such as factory automation controllers, outdoor metering, and transportation electronics - all while maintaining full functionality of the AT45DB021D-SH-B's RapidS™ interface and security features.

What hardware and software protection mechanisms does the AT45DB021D-SH-B provide?

The AT45DB021D-SH-B implements three-tiered protection: (1) hardware Write Protect (WP) pin that overrides all software commands when asserted; (2) Sector Protection Register enabling software-controlled lock/unlock per sector; and (3) Sector Lockdown command that permanently disables further protection changes for selected sectors. Additionally, its 128-byte security register contains 64-byte user-programmable space and a unique 64-byte device identifier - ensuring the AT45DB021D-SH-B meets requirements for secure boot and anti-counterfeiting in certified embedded systems.