Renesas AT25SF321B-SHB-B

Overview

AT25SF321B-SHB-B from Renesas Electronics is a 32-Mbit SPI serial flash memory IC supporting dual I/O and quad I/O operations, 133 MHz max clock frequency, 2.7–3.6 V single supply, and execute-in-place (XiP) capability for embedded boot and code storage applications.

For engineers reviewing the AT25SF321B-SHB-B datasheet, AT25SF321B-SHB-B pinout, AT25SF321B-SHB-B application, or AT25SF321B-SHB-B equivalent, key selection criteria include quad-SPI timing compliance, 4 kB/32 kB/64 kB erase granularity, OTP security registers, SFDP support, and industrial temperature range (-40°C to +85°C).

Technical Context

The AT25SF321B-SHB-B implements a flexible SPI interface with full mode 0 and mode 3 compatibility, enabling dual-output (1-1-2), dual-I/O (1-2-2), quad-output (1-1-4), and quad-I/O (1-4-4, 0-4-4) read protocols. Its architecture supports continuous read with wrap and XiP-optimized command sequences.

Internal protection logic includes non-volatile status register locking, user-definable memory array protection zones (start/end), and hardware write-protection via the WP pin. Three 256-byte OTP security registers provide immutable device identity and secure configuration storage.

Key Specifications

Pinout & Package

AT25SF321B-SHB-B is packaged in an 8-pin, 150-mil narrow SOIC (Small Outline Integrated Circuit) with standard JEDEC pinout and RoHS-compliant green finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Winbond W25Q32JW and Macronix MX25L3233F, the AT25SF321B-SHB-B uniquely combines SFDP auto-configuration, three OTP registers, and full erase suspend/resume - making it optimal for secure, field-upgradable embedded systems requiring firmware agility and long-term data integrity.

Availability

AT25SF321B-SHB-B is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, and automotive infotainment systems requiring stable component supply, extended temperature operation, and secure firmware storage.

Supply support for AT25SF321B-SHB-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 industrial, automotive, and IoT markets.

The AT25SF321B belongs to Renesas' high-reliability serial flash product line, engineered specifically for embedded systems demanding secure boot, execute-in-place performance, and long-term data retention under industrial thermal stress.

FAQ

What is the maximum SPI clock frequency supported by the AT25SF321B-SHB-B?

The AT25SF321B-SHB-B supports a maximum SPI clock frequency of 133 MHz in quad-I/O (1-4-4 and 0-4-4) modes. This enables high-throughput read operations essential for execute-in-place (XiP) applications. The device maintains timing compliance across its full industrial temperature range (-40°C to +85°C), and the 133 MHz rating is validated per AC characteristics in the official Renesas datasheet DS-AT25SF321B-179 Rev. I.

Does the AT25SF321B-SHB-B support execute-in-place (XiP) functionality?

Yes, the AT25SF321B-SHB-B explicitly supports execute-in-place (XiP) through optimized quad-I/O read commands including the 0-4-4 protocol, which eliminates opcode transmission overhead and enables continuous instruction fetch directly from flash. This capability is confirmed in the Product Overview section of the Renesas datasheet and is enhanced by features like continuous read with wrap and high-frequency timing margins - all integral to the AT25SF321B-SHB-B's architecture.

How many One-Time Programmable (OTP) security registers does the AT25SF321B-SHB-B have, and what is their size?

The AT25SF321B-SHB-B includes three 256-byte One-Time Programmable (OTP) security registers, totaling 768 bytes of immutable storage. These registers are used for device-specific data such as unique identifiers, cryptographic keys, or secure boot configuration. Once programmed, they cannot be erased or rewritten - a feature verified in the "Features" and "Security Register Commands" sections of the official Renesas datasheet DS-AT25SF321B-179.

What package type is used for the AT25SF321B-SHB-B variant?

The AT25SF321B-SHB-B uses an 8-pin, 150-mil narrow SOIC package with standard JEDEC footprint and RoHS-compliant green finish. This package is explicitly listed in the "Ordering Information" section (page 58) and illustrated in Figure 1 of the Renesas datasheet DS-AT25SF321B-179 Rev. I. It is distinct from the wide SOIC (208-mil) and DFN variants offered in the same family.

Does the AT25SF321B-SHB-B support Serial Flash Discoverable Parameters (SFDP)?

Yes, the AT25SF321B-SHB-B implements the JEDEC-standard Serial Flash Discoverable Parameters (SFDP) register, accessible via command 5Ah. This allows host systems to dynamically query timing parameters, erase block sizes, and programming characteristics without relying on hardcoded values - a capability documented in the "Features" and "Read Commands" sections of the Renesas datasheet DS-AT25SF321B-179 Rev. I.