Microchip Technology 24AA256T-E/MNY

Overview

24AA256T-E/MNY from Microchip Technology is a 256-Kbit I²C-compatible serial EEPROM with 32K × 8 organization, 1.7V–5.5V single-supply operation, hardware write-protect (WP), and 64-byte page write buffer. It supports up to eight devices on one bus via A0/A1/A2 address inputs and delivers 400 kHz max clock frequency at V_CC ≥ 2.5V for industrial temperature range (−40°C to +85°C). Used in embedded systems for parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 24AA256T-E/MNY datasheet, 24AA256T-E/MNY pinout, 24AA256T-E/MNY application, or 24AA256T-E/MNY equivalent, key selection criteria include low-voltage operation down to 1.7V, 1 µA standby current, Schmitt-trigger I²C inputs for noise immunity, self-timed 5 ms write cycle, and MNY package compatibility with 8-lead TSSOP footprint.

Technical Context

The 24AA256T-E/MNY implements a two-wire I²C interface with open-drain SDA/SCL pins requiring external pull-ups, and uses internal address pointer logic for sequential reads across the full 256-Kbit memory space. Its EEPROM array is organized into 32,768 × 8 bits with page boundaries aligned every 64 bytes.

Write protection is controlled by the WP pin: tied to V_SS enables writes; tied to V_CC disables writes while permitting reads. Addressing uses a 7-bit client address (1010 A2 A1 A0) followed by R/W bit, supporting cascaded multi-device configurations with hardware-selectable chip addresses.

Key Specifications

Pinout & Package

24AA256T-E/MNY is packaged in an 8-lead TSSOP (MNY), with lead pitch of 0.65 mm and body dimensions of 4.4 mm × 3.0 mm × 1.2 mm. Pin 1 is marked with a dot or bevel; pin numbering follows standard counter-clockwise orientation from top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC256-I/P, the 24AA256T-E/MNY enables lower-voltage operation and broader system compatibility; versus AT24C256-10PU-2.7, it offers automotive qualification and guaranteed 1.7V functionality at the expense of peak I²C speed.

Availability

24AA256T-E/MNY is available at Aetrix Electronics and suitable for smart meter calibration storage, industrial PLC configuration memory, medical device usage logs, and automotive body control module settings requiring stable component supply across extended temperature and voltage ranges.

Supply support for 24AA256T-E/MNY 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 components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24AA256T-E/MNY belongs to Microchip's 24XX256 family of I²C serial EEPROMs, engineered for ultra-low-power, wide-voltage-range nonvolatile data storage in industrial, medical, and automotive applications demanding high reliability and long data retention.

FAQ

What is the minimum supply voltage required for reliable operation of the 24AA256T-E/MNY?

The 24AA256T-E/MNY operates reliably down to 1.7V across its specified industrial temperature range (−40°C to +85°C). Below 2.5V, the maximum I²C clock frequency is limited to 100 kHz per datasheet Table 1-2. This makes the 24AA256T-E/MNY suitable for battery-powered or energy-harvesting systems where supply voltage may dip below 2.5V during operation.

How does the hardware write-protect (WP) pin function on the 24AA256T-E/MNY?

On the 24AA256T-E/MNY, the WP pin is sampled at the Stop bit of each write command. When tied to V_CC, it disables all write operations (byte and page) while allowing unrestricted reads. When tied to V_SS, writes are enabled. The WP state cannot be changed mid-cycle-the pin must remain stable through the entire Stop condition to take effect.

Can multiple 24AA256T-E/MNY devices share the same I²C bus, and how is addressing managed?

Yes-up to eight 24AA256T-E/MNY devices can share one I²C bus using the A0, A1, and A2 pins to configure unique 3-bit chip addresses. Each pin must be hardwired to V_SS or V_CC. The resulting 7-bit client address is formed as '1010 A2 A1 A0', enabling distinct addressing without software configuration or external logic.

What is the purpose and behavior of the 64-byte page write buffer in the 24AA256T-E/MNY?

The 64-byte page write buffer in the 24AA256T-E/MNY allows up to 64 bytes to be loaded into on-chip latches before initiating a single self-timed 5 ms write cycle. If more than 64 bytes are sent before the Stop condition, the address counter wraps within the current page-overwriting earlier data. This buffer reduces I²C transaction overhead and improves effective write throughput.

Is the 24AA256T-E/MNY qualified for automotive applications?

No-the 24AA256T-E/MNY carries the 'E' suffix indicating Extended temperature range (−40°C to +125°C), but it is not AEC-Q100 qualified. Only the 24AA256 variants explicitly marked 'A' (e.g., 24AA256-I/SM) are AEC-Q100 Grade 2 qualified. For automotive body control or infotainment modules requiring qualification, consult Microchip's AEC-Q100-certified 24AA256 variants instead of the 24AA256T-E/MNY.