Renesas AT45DB021E-SHN-B

Overview

AT45DB021E-SHN-B from Renesas Electronics is a 2-Mbit serial DataFlash memory with extra 64 kbits, operating from 1.65 V to 3.6 V, supporting SPI modes 0 and 3, up to 85 MHz clock rate, and featuring a 264-byte page size (default), one 256/264-byte SRAM buffer, and hardware/software sector protection. It is used in embedded firmware storage, voice logging, and boot code retention where low-pin-count, low-power sequential access is required.

For engineers reviewing the AT45DB021E-SHN-B datasheet, AT45DB021E-SHN-B pinout, AT45DB021E-SHN-B application, or AT45DB021E-SHN-B equivalent, key selection considerations include its RapidS™ high-speed read capability, ultra-deep power-down current (200 nA typical), configurable page size, dual erase granularity (page/block/sector/chip), and OTP security register with factory-unique 64-byte ID.

Technical Context

The AT45DB021E-SHN-B implements a two-buffer architecture: one main memory array (1,024 × 256/264 bytes) and one dedicated SRAM data buffer (256/264 bytes), enabling concurrent read-modify-write operations without external RAM. Its command set supports legacy and RapidS™ read modes (0Bh, 03h, 01h opcodes), buffer-to-main-memory programming with or without built-in erase, and auto page rewrite.

It integrates JEDEC-standard Manufacturer and Device ID read (9Fh), status register monitoring (D7h), and dual protection mechanisms: software-configurable sector protection (32 kB sectors) and hardware-controlled lockdown via WP pin. Sector lockdown permanently disables write/erase for selected sectors, and the 128-byte OTP Security Register contains 64 bytes factory-programmed unique ID and 64 bytes user-programmable space.

Key Specifications

Pinout & Package

AT45DB021E-SHN-B is packaged in an 8-lead SOIC 150-mil wide (JEDEC MS-012AA) with exposed pad not internally connected. Pin functions are electrically validated per Renesas DS-AT45DB021E-8789 Rev. N, Page 7.

Key Features

Applications

Equivalent & Alternatives

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

Compared with W25Q20EW and MX25L2006E, AT45DB021E-SHN-B uniquely delivers SRAM-buffered sequential access, sub-µA power-down, and factory-unique OTP ID - making it optimal for battery-powered, secure, and E²PROM-emulation-critical embedded systems.

Availability

AT45DB021E-SHN-B is available at Aetrix Electronics and suitable for firmware storage, voice/data logging, industrial HMI boot memory, and medical device configuration storage requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for AT45DB021E-SHN-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 memory solutions for automotive, industrial, and IoT markets.

The AT45DB021E-SHN-B belongs to Renesas' DataFlash family, designed specifically for low-pin-count, low-voltage, sequential-access nonvolatile storage in space- and power-constrained embedded systems.

FAQ

What is the default page size of the AT45DB021E-SHN-B?

The AT45DB021E-SHN-B has a default page size of 264 bytes, but it can be factory pre-configured for 256 bytes. This configuration is fixed per unit and cannot be changed in-system. The 264-byte layout includes 8 bytes of spare area commonly used for ECC or metadata, while the 256-byte variant maximizes usable payload density. Both configurations maintain full compatibility with the AT45DB021E-SHN-B command set and timing specifications.

Does the AT45DB021E-SHN-B support true byte-level writes like EEPROM?

The AT45DB021E-SHN-B does not support true random byte writes, but enables E²PROM emulation via its integrated SRAM buffer and three-step read-modify-write operation: (1) transfer target page to buffer, (2) modify desired bytes in buffer, (3) write buffer back to main memory. This eliminates external RAM dependency and achieves byte-alterability with deterministic latency - a core design feature of the AT45DB021E-SHN-B architecture.

How does the WP pin function on the AT45DB021E-SHN-B?

On the AT45DB021E-SHN-B, the WP (Write Protect) pin is an active-low hardware control that enforces sector protection defined in the Sector Protection Register. When WP is asserted (low), all sectors marked protected in that register become immune to program and erase commands - even if software attempts to clear protection. This provides a physical fail-safe against accidental or malicious firmware corruption, independent of SPI command execution.

What is the purpose of the 128-byte Security Register in the AT45DB021E-SHN-B?

The 128-byte Security Register in the AT45DB021E-SHN-B comprises two 64-byte fields: the first is factory-programmed with a globally unique identifier (UID) at wafer test, and the second is user-programmable. This register supports secure boot key binding, device authentication, and traceability. Once written, the OTP portion cannot be altered - a hardware-enforced security feature intrinsic to the AT45DB021E-SHN-B's design.

Can the AT45DB021E-SHN-B operate at 1.65 V during high-speed read operations?

Yes, the AT45DB021E-SHN-B is fully specified for 85 MHz RapidS™ read operation down to 1.65 V, as confirmed in Section 20.2 (DC and AC Operating Range) of the official datasheet. Its internal charge pump and optimized logic ensure timing compliance across the entire 1.65–3.6 V supply range - eliminating voltage scaling trade-offs between power efficiency and performance in the AT45DB021E-SHN-B.