Microchip Technology 25AA320T-I/SN

Overview

25AA320T-I/SN from Microchip Technology Inc. is a 32 Kbit (4096 × 8) SPI-compatible serial EEPROM with 1.8–5.5 V supply range, 1 MHz max clock frequency, and industrial temperature rating (−40°C to +85°C). It features hardware write protection via WP pin, HOLD functionality for interrupt-safe bus suspension, and 32-byte page write capability. It is used in embedded systems for storing calibration data, configuration settings, and firmware parameters where low-power nonvolatile memory is required.

For engineers reviewing the 25AA320T-I/SN datasheet, 25AA320T-I/SN pinout, 25AA320T-I/SN application, or 25AA320T-I/SN equivalent, key selection criteria include V_CC compatibility down to 1.8 V, guaranteed 1 MHz SPI timing at 1.8 V, industrial-grade reliability (1M write/erase cycles, >200-year data retention), and SOIC-8 package suitability for space-constrained PCB layouts.

Technical Context

The 25AA320T-I/SN implements a standard SPI Mode 0,0 interface with separate SI (data in) and SO (data out) lines, CS-controlled device selection, and SCK-synchronized transfers. Its internal architecture includes an 8-bit instruction register, auto-incrementing address pointer for sequential reads, and a STATUS register with WIP, WEL, BP0/BP1, and WPEN bits for real-time status monitoring and configurable block protection.

Write operations require explicit WREN instruction before WRITE or WRSR commands; all writes are self-timed with 5 ms maximum internal cycle time. The HOLD pin suspends ongoing SPI communication without resetting the sequence, enabling host microcontrollers to service higher-priority interrupts while preserving transaction state.

Key Specifications

Pinout & Package

25AA320T-I/SN is supplied in an 8-pin plastic SOIC (150 mil body) package per Microchip's part numbering system (SN suffix). Pin 1 is CS, pin 2 is SO, pin 3 is WP, pin 4 is V_SS, pin 5 is SI, pin 6 is SCK, pin 7 is HOLD, and pin 8 is V_CC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA320T-I/SN, the 25AA320A-I/SN offers identical electrical and functional behavior with improved process reliability, while AT25DF321A-SHN-T trades hardware protection and interrupt safety for higher density and speed-making it unsuitable as a drop-in replacement.

Availability

25AA320T-I/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, smart energy metering, and automotive body control module applications requiring stable component supply across extended product lifecycles.

Supply support for 25AA320T-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 microcontrollers, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA320T-I/SN belongs to Microchip's 25XX320 family of SPI serial EEPROMs, designed specifically for low-voltage, low-power embedded systems requiring robust, pin-efficient nonvolatile storage with hardware security features.

FAQ

What is the minimum V_CC required for reliable operation of the 25AA320T-I/SN?

The 25AA320T-I/SN operates reliably down to 1.8 V across its full industrial temperature range (−40°C to +85°C). At this voltage, it supports up to 1 MHz SPI clock frequency with guaranteed timing margins per DS21227F AC characteristics table. Below 1.8 V, functionality is not specified and may result in incomplete writes or read errors.

Does the 25AA320T-I/SN support page write operations, and what is the maximum page size?

Yes, the 25AA320T-I/SN supports page write operations with a fixed page size of 32 bytes. Writes must remain within a single page boundary (addresses xxxxxxxx xxx00000 to xxxxxxxx xxx11111); crossing page boundaries causes the internal address counter to roll over and overwrite earlier bytes in the same page.

How does the HOLD pin function during an active SPI transaction on the 25AA320T-I/SN?

The HOLD pin on the 25AA320T-I/SN suspends an ongoing SPI transaction when pulled low while SCK is low. During HOLD, SI, SCK, and SO enter high-impedance states and ignore input transitions except CS. To resume, HOLD must be raised while SCK remains low-ensuring deterministic restart without retransmission.

What write protection mechanisms are implemented in the 25AA320T-I/SN?

The 25AA320T-I/SN implements three-tiered write protection: (1) software-controlled WREN/WRDI latching, (2) STATUS register BP0/BP1 bits for 0%/25%/50%/100% array block locking, and (3) hardware WP pin enabled only when WPEN bit is set-allowing flexible, layered security against accidental or malicious writes.

Is the 25AA320T-I/SN pin-compatible with other members of the 25XX320 family such as 25LC320T-I/SN?

No-the 25AA320T-I/SN is not pin-compatible with 25LC320T-I/SN or 25C320T-I/SN. While all share the same SOIC-8 package and pin assignments, their V_CC ranges differ (1.8–5.5 V vs. 2.5–5.5 V vs. 4.5–5.5 V), and mixing them risks undervoltage operation or excessive current draw outside specified limits.