Microchip Technology 25AA320A-I/SN

Overview

25AA320A-I/SN from Microchip Technology is a 32-Kbit SPI Serial EEPROM with 4096 × 8-bit organization, 32-byte page size, and industrial temperature range (−40°C to +85°C). It operates from 1.8V to 5.5V, supports up to 10 MHz clock at 4.5–5.5V, and delivers 5 µA standby current - enabling low-power data logging in battery-backed microcontroller systems.

For engineers reviewing the 25AA320A-I/SN datasheet, 25AA320A-I/SN pinout, 25AA320A-I/SN application, or 25AA320A-I/SN equivalent, key selection criteria include SPI interface compatibility, hardware write protection via WP pin, HOLD functionality for interrupt-safe bus arbitration, and AEC-Q100 qualification for automotive-grade reliability.

Technical Context

The 25AA320A-I/SN implements a standard SPI Mode 0,0/Master-Slave interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, and optional HOLD/WP control signals. Its internal architecture includes a status register with WIP, WEL, BP0/BP1, and WPEN bits for configurable block protection and write-enable management.

It uses self-timed internal write cycles (≤5 ms), supports sequential read across address boundaries with automatic rollover, and features built-in power-on data protection, write-enable latch reset on power-up, and high-impedance SO during CS high - enabling multi-device SPI bus sharing without external tri-state logic.

Key Specifications

Pinout & Package

25AA320A-I/SN is packaged in an 8-lead narrow SOIC (SN) with 1.27 mm pitch, 3.90 mm body width, and JEDEC MS-012AC compliant footprint. The package supports reflow soldering and is RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25LC320A-I/SN, the 25AA320A-I/SN supports lower-voltage operation down to 1.8V - critical for energy-harvesting sensors - while both share identical pinout, HOLD functionality, and AEC-Q100 qualification. The AT25DF321A-SHN-B offers higher density but sacrifices deterministic interrupt handling and fine-grained write protection.

Availability

25AA320A-I/SN is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor nodes, medical infusion pumps, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for 25AA320A-I/SN 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

Microchip Technology Inc. is a leading provider of microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA320A belongs to Microchip's serial EEPROM product line, designed specifically for robust, low-power, SPI-based nonvolatile data storage in automotive, industrial, and medical applications where reliability and long-term data integrity are critical.

FAQ

What is the maximum clock frequency supported by the 25AA320A-I/SN?

The 25AA320A-I/SN supports up to 10 MHz clock frequency when VCC is between 4.5V and 5.5V. At 2.5V ≤ VCC < 4.5V, the maximum clock drops to 5 MHz, and at 1.8V ≤ VCC < 2.5V, it is limited to 3 MHz. These stepped limits ensure reliable timing margin across the full 1.8–5.5V supply range. The 25AA320A-I/SN datasheet specifies these values in Table 1-2 under FCLK parameter.

Does the 25AA320A-I/SN support hardware write protection?

Yes, the 25AA320A-I/SN supports hardware write protection via the WP pin in conjunction with the WPEN bit in its STATUS register. When WP is low and WPEN = 1, writes to nonvolatile STATUS bits are disabled. This protects critical configuration data even if firmware erroneously attempts to modify protection settings. The 25AA320A-I/SN implements this per Section 2.3 and Table 3-4 of its datasheet.

What package type does the 25AA320A-I/SN use?

The 25AA320A-I/SN uses an 8-lead narrow SOIC package (JEDEC MS-012AC), designated by the "SN" suffix. It has a 3.90 mm body width, 1.27 mm lead pitch, and complies with RoHS requirements. Package dimensions and land pattern recommendations are documented in Microchip Drawing No. C04-057-SN Rev F. This package is compatible with standard surface-mount assembly processes.

How does the HOLD function operate on the 25AA320A-I/SN?

The HOLD pin on the 25AA320A-I/SN suspends ongoing SPI communication without resetting the internal state. To activate, HOLD must be pulled low while SCK is low; SO immediately enters high-impedance. Resuming requires bringing HOLD high while SCK remains low. During hold, SI and SCK transitions are ignored, allowing the host MCU to service interrupts. This behavior is defined in Section 2.6 and Figure 1-1 of the 25AA320A-I/SN datasheet.

Is the 25AA320A-I/SN qualified for automotive applications?

Yes, the 25AA320A-I/SN is AEC-Q100 qualified for automotive applications (Grade 2, −40°C to +105°C ambient). While the "I" suffix denotes Industrial temperature range (−40°C to +85°C), the device itself meets AEC-Q100 stress test requirements, making it suitable for under-hood and cabin modules where extended reliability is mandated. This qualification is explicitly stated in the Features section of the 25AA320A-I/SN datasheet.