Microchip Technology 25AA320-I/P

Overview

25AA320-I/P 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 32-byte page write capability, 5 ms max internal write cycle time, and hardware write protection via WP pin and STATUS register. It is used for nonvolatile parameter storage in microcontroller-based embedded systems requiring low-power, reliable data retention.

For engineers reviewing the 25AA320-I/P datasheet, 25AA320-I/P pinout, 25AA320-I/P application, or 25AA320-I/P equivalent, key selection criteria include its 1.8 V minimum operating voltage, 500 nA typical standby current, block write protection granularity (none/¼/½/all), and compatibility with standard SPI Mode 0,0 and Mode 1,1 interfaces.

Technical Context

The 25AA320-I/P implements a true SPI slave interface with separate SI (data in) and SO (data out) lines, supporting full-duplex read and half-duplex write operations. Its command set includes READ (0x03), WRITE (0x02), WREN (0x06), WRDI (0x04), RDSR (0x05), and WRSR (0x01), with all transfers MSB-first and address auto-increment during sequential reads.

It integrates on-chip high-voltage generation for EEPROM programming, self-timed erase/write cycles, and power-on reset logic that clears the write enable latch. The HOLD pin enables transaction suspension without bus reinitialization, and the STATUS register provides real-time visibility into WIP (Write-In-Process), WEL (Write Enable Latch), and BP0/BP1 (block protection) states.

Key Specifications

Pinout & Package

25AA320-I/P is supplied in an 8-pin Plastic Dual In-line Package (PDIP) with 300 mil body width. Pin spacing is 0.1 inch (2.54 mm), and lead finish is matte tin (Pb-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA320-I/P, the 25AA320A-I/P offers identical functionality with improved process reliability, while the AT25DF321A-SSH-T targets different use cases entirely-its higher density and quad-SPI interface make it unsuitable as a direct replacement for configuration storage where low voltage, low power, and simple SPI are essential.

Availability

25AA320-I/P 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 and long-term obsolescence management.

Supply support for 25AA320-I/P 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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA320-I/P belongs to Microchip's legacy SPI Serial EEPROM product line, designed specifically for low-voltage, low-power, and high-reliability nonvolatile data storage in cost-sensitive embedded systems.

FAQ

What is the minimum supply voltage required for reliable operation of the 25AA320-I/P?

The 25AA320-I/P operates reliably down to 1.8 V across the full industrial temperature range (−40°C to +85°C). Below this voltage, read and write functions are not guaranteed per specification. This 1.8 V minimum enables direct integration with modern ultra-low-power microcontrollers and battery-powered systems without voltage boosting circuitry. The 25AA320-I/P maintains full SPI compatibility and timing compliance at 1.8 V, including 1 MHz clock support and valid logic thresholds.

Does the 25AA320-I/P support standard SPI modes, and which ones?

Yes, the 25AA320-I/P supports both SPI Mode 0,0 (CPOL = 0, CPHA = 0) and Mode 1,1 (CPOL = 1, CPHA = 1). Data is sampled on the rising edge of SCK for SI and output on the falling edge for SO. These modes align with common microcontroller SPI peripherals including PIC, AVR, and ARM Cortex-M families. The 25AA320-I/P does not support Mode 0,1 or Mode 1,0, and its timing diagrams explicitly define setup/hold relationships for the supported modes only.

How does the HOLD pin function during an active SPI transaction on the 25AA320-I/P?

The HOLD pin on the 25AA320-I/P suspends an ongoing SPI sequence without resetting internal state. When asserted low while SCK is low, SI/SO/SCK enter high-impedance and all inputs except CS are ignored. Communication resumes from the exact point of suspension when HOLD is returned high with SCK low. This allows the host MCU to service urgent interrupts and return seamlessly-critical for deterministic real-time systems. The 25AA320-I/P does not require retransmission of the instruction or address after resume.

What write protection mechanisms are implemented in the 25AA320-I/P?

The 25AA320-I/P implements three layered write protection: (1) Software-controlled via WREN/WRDI instructions and WEL bit in STATUS register; (2) Hardware-enabled via WP pin combined with WPEN bit; (3) Block-level via BP0/BP1 bits defining protected memory segments (none/¼/½/all). Protection is nonvolatile and persists across power cycles. The WP pin has no effect unless WPEN = 1, allowing safe board-level grounding during development while retaining full programmability.

Is the 25AA320-I/P pin-compatible with newer revisions like the 25AA320A-I/P?

Yes, the 25AA320-I/P is fully pin-compatible and functionally identical to the 25AA320A-I/P. Both share identical PDIP-8 packaging, pinout, electrical specifications, instruction set, and timing behavior. The 'A' suffix denotes a revised silicon version with enhanced ESD performance and updated process qualification-but no changes to footprint, signal mapping, or software interface. Migration to 25AA320A-I/P requires no PCB or firmware modifications and is recommended for new designs.