Microchip Technology 25AA320A-I/MS

Overview

25AA320A-I/MS from Microchip Technology Inc. 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 - used for nonvolatile parameter storage in embedded controllers, sensor calibration modules, and power supply configuration.

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

Technical Context

The 25AA320A-I/MS implements a standard SPI Mode 0,0 or Mode 1,1 interface with separate SI (data-in) and SO (data-out) lines, CS-controlled selection, and SCK-synchronized latching on rising edge (SI) and falling edge (SO). Its internal architecture includes a status register with WIP, WEL, BP0/BP1, and WPEN bits enabling configurable block protection and hardware write lock.

It features self-timed internal write cycles (≤5 ms), sequential read capability with automatic address increment, and HOLD pin support that suspends ongoing transfers without resetting the serial sequence - critical for real-time systems requiring deterministic interrupt latency.

Key Specifications

Pinout & Package

25AA320A-I/MS is housed in an 8-lead MSOP (150 mil) package with exposed pad (optional VSS connection), measuring 3.0 mm × 3.0 mm × 1.0 mm. Pin numbering follows standard MSOP orientation with Pin 1 at top-left corner when marking side faces up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25LC320A-I/MS, the 25AA320A-I/MS extends operational voltage down to 1.8V while retaining identical packaging and SPI behavior; versus AT25DF321A-MAU-T, it provides dedicated hardware write protection and HOLD support essential for robust parameter storage in deterministic embedded systems.

Availability

25AA320A-I/MS is available at Aetrix Electronics and suitable for industrial sensor calibration, motor drive configuration, and smart energy metering requiring stable component supply across extended production lifecycles.

Supply support for 25AA320A-I/MS 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 25AA320A belongs to Microchip's serial EEPROM product line, engineered for reliable, low-power nonvolatile storage in space-constrained embedded systems where SPI simplicity and AEC-Q100 compliance are critical.

FAQ

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

The 25AA320A-I/MS supports up to 10 MHz clock frequency when VCC is between 4.5V and 5.5V. At lower voltages (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 limits ensure reliable setup/hold timing across voltage and temperature ranges, and must be observed in all 25AA320A-I/MS designs.

Does the 25AA320A-I/MS require external pull-up resistors on its SPI lines?

The 25AA320A-I/MS does not require external pull-ups on SI, SCK, or CS - these inputs are CMOS with rail-to-rail thresholds. However, SO is an open-drain output and requires an external pull-up resistor (typically 4.7 kΩ to VCC) to ensure valid high-level signaling on shared SPI buses. This is mandatory for correct 25AA320A-I/MS read operation.

How does the HOLD pin function during an active SPI transaction in the 25AA320A-I/MS?

When the HOLD pin is pulled low during an active SPI transaction, the 25AA320A-I/MS immediately places SO in high-impedance state and ignores further SI/SCK transitions until HOLD is returned high while SCK is low. The internal address pointer and command state are preserved, allowing seamless resumption - a key feature for real-time systems using the 25AA320A-I/MS.

Can the 25AA320A-I/MS be used in automotive applications?

Yes - the 25AA320A-I/MS is AEC-Q100 qualified for Grade 2 (−40°C to +105°C ambient), and the "I" suffix denotes industrial temperature grade (−40°C to +85°C), making it suitable for cabin and engine-bay-adjacent automotive subsystems. Its built-in write protection, HOLD functionality, and 200-year data retention meet stringent automotive EEPROM requirements.

What happens to the write enable latch after a successful write operation in the 25AA320A-I/MS?

After a successful WRITE, WRSR, or WRDI instruction, the write enable latch (WEL bit) in the 25AA320A-I/MS is automatically reset to '0'. This prevents unintended writes and mandates reissuing WREN before subsequent write attempts - a fundamental safety mechanism enforced by the 25AA320A-I/MS hardware.