Renesas AT25SF321B-SSHB-B

Overview

AT25SF321B-SSHB-B from Renesas Electronics is a 32-Mbit SPI serial flash memory IC designed for embedded boot code and XiP (execute-in-place) applications. It operates from a single 2.7–3.6 V supply, supports SPI modes 0/3, delivers up to 133 MHz read speed in quad I/O (1-4-4) mode, and features 4 kB/32 kB/64 kB block erase with typical times of 55 ms / 120 ms / 200 ms. It is used in industrial controllers requiring fast, reliable nonvolatile storage with hardware write protection.

For engineers reviewing the AT25SF321B-SSHB-B datasheet, AT25SF321B-SSHB-B pinout, AT25SF321B-SSHB-B application, or AT25SF321B-SSHB-B equivalent, key selection criteria include quad-SPI timing compliance, deep power-down current (1 µA), OTP security register support, SFDP register availability, and SOIC-8 (150-mil) package compatibility with legacy PCB footprints.

Technical Context

The AT25SF321B-SSHB-B implements a flexible SPI interface supporting standard, 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) command formats - enabling scalable bandwidth from basic SPI to 532 MB/s effective throughput. Its memory array is organized into 1024 × 4 kB blocks, with dedicated page program (1–256 bytes) and multi-level erase granularity optimized for firmware updates and data logging.

Internal control logic integrates erase/program suspend-resume capability, JEDEC-standard manufacturer/device ID, and three 256-byte one-time programmable (OTP) security registers. Protection is enforced via status register bits (SRP0/SRP1) and hardware WP/HOLD pins, with configurable lock-down regions at memory start or end using non-volatile settings.

Key Specifications

Pinout & Package

AT25SF321B-SSHB-B is packaged in an 8-pin, 150-mil narrow SOIC (Small Outline Integrated Circuit) with standard pin pitch and footprint. This RoHS-compliant green package supports reflow soldering and is compatible with automated assembly lines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Winbond W25Q32JW and Micron MT25QL32ABA, the AT25SF321B-SSHB-B uniquely combines OTP security registers, SFDP compliance, and 3.3 V-only simplicity - making it optimal for cost-sensitive industrial firmware storage where cryptographic key immutability and driver portability are essential.

Availability

AT25SF321B-SSHB-B is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, and medical diagnostic devices requiring stable component supply across multi-year production lifecycles.

Supply support for AT25SF321B-SSHB-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 specializing in microcontrollers, analog, power, and memory solutions for industrial, automotive, and enterprise applications.

The AT25SF321B-SSHB-B belongs to Renesas' AT25SF family of SPI flash memories, engineered specifically for robust, high-reliability embedded boot and XiP use cases in temperature-stressed environments.

FAQ

What is the operating temperature range for the AT25SF321B-SSHB-B?

The AT25SF321B-SSHB-B is rated for industrial operation from −40 °C to +85 °C. This range is validated per JEDEC JESD22-A104 and supports deployment in factory automation controllers, outdoor gateways, and vehicle cabin electronics without thermal derating. The AT25SF321B-SSHB-B maintains full specification compliance-including 133 MHz read speed and 1 µA deep power-down-across this entire range.

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

Yes, the AT25SF321B-SSHB-B explicitly supports XiP through quad-I/O (1-4-4) and continuous read (0-4-4) command modes, which eliminate opcode overhead and deliver deterministic access latency. Its 133 MHz maximum clock frequency and low-latency read architecture allow microcontrollers to fetch instructions directly from flash without copying to RAM. The AT25SF321B-SSHB-B datasheet confirms XiP suitability in Section 1 (Product Overview).

How many one-time programmable (OTP) registers does the AT25SF321B-SSHB-B include?

The AT25SF321B-SSHB-B includes three independent 256-byte OTP security registers, accessible via dedicated commands (42h program, 48h read, 44h erase). These registers are physically fused on write and cannot be reprogrammed-making them suitable for storing cryptographic keys, device serial numbers, or calibration constants. Each register is individually erasable only once, and the AT25SF321B-SSHB-B enforces strict access control via status register locks.

What package type is used for the AT25SF321B-SSHB-B?

The AT25SF321B-SSHB-B uses an 8-pin, 150-mil narrow SOIC package (also referenced as "SOIC-8 NB"). This RoHS-compliant, lead-free package has a 1.27 mm pitch and standard JEDEC MS-012AC dimensions. It is compatible with existing PCB footprints for legacy SPI flash devices and supports both reflow and wave soldering processes. The "-SSHB-B" suffix explicitly denotes this SOIC-8 narrow-body variant.

Can the AT25SF321B-SSHB-B be used with standard SPI controllers without quad-SPI extensions?

Yes, the AT25SF321B-SSHB-B is fully backward-compatible with standard SPI controllers supporting modes 0 and 3. It executes basic read (03h), fast read (0Bh), and program/erase commands using single I/O (SI/SO) operation. Quad-SPI features (1-4-4, 0-4-4) are optional enhancements; the AT25SF321B-SSHB-B defaults to standard SPI mode on power-up and requires explicit status register configuration to enable quad functionality.