Microchip Technology 24AA256T-E/SN

Overview

24AA256T-E/SN from Microchip Technology is a 256-Kbit I²C serial EEPROM in an 8-lead SOIC package, supporting 1.7V–5.5V operation, 400 kHz max clock frequency (100 kHz below 2.5V), and industrial temperature range (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protection via WP pin, and Schmitt-trigger inputs for noise immunity - deployed in embedded system configuration storage and sensor calibration data retention.

For engineers reviewing the 24AA256T-E/SN datasheet, 24AA256T-E/SN pinout, 24AA256T-E/SN application, or 24AA256T-E/SN equivalent, key selection criteria include low-voltage compatibility (down to 1.7V), I²C bus timing compliance at 400 kHz, page-write endurance (1M cycles), and SOIC-8 footprint availability with hardware write-protect functionality.

Technical Context

The 24AA256T-E/SN implements a two-wire I²C-compatible interface with open-drain SDA/SCL requiring external pull-ups, and uses internal address pointer logic for sequential reads across its 32K × 8-bit memory array. Its write cycle is self-timed (max 5 ms) and supports both byte and page writes, with automatic address wraparound at 0x7FFF boundary.

Chip addressing uses A0–A2 pins (hardwired or controlled) to enable up to eight devices on one bus; for the SOIC package (SN), all three address pins are functional and connected. The WP pin samples state at Stop condition to enable/disable writes, and Schmitt-trigger inputs on SDA/SCL provide defined hysteresis (≥0.05 VCC) for robust noise suppression.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (SN), 3.90 mm body width, RoHS-compliant matte tin finish, JEDEC MS-012AC standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC256-I/SN and AT24C256-10PU-2.7, the 24AA256T-E/SN uniquely supports 1.7V operation while maintaining full 400 kHz I²C compatibility and identical SOIC-8 footprint - making it the only choice for ultra-low-voltage embedded systems requiring long-term data integrity.

Availability

24AA256T-E/SN is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and smart energy meter firmware patch storage requiring stable component supply across extended product lifecycles.

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

The 24AA256T-E/SN belongs to Microchip's 24XX256 family of I²C EEPROMs, designed specifically for low-power, wide-voltage-range embedded applications where data persistence, noise immunity, and bus scalability are critical.

FAQ

What is the maximum I²C clock frequency supported by the 24AA256T-E/SN?

The 24AA256T-E/SN supports up to 400 kHz when V_CC ≥ 2.5V, and 100 kHz when V_CC < 2.5V. This dual-speed behavior is explicitly defined in the datasheet's AC characteristics table and ensures reliable operation across its full 1.7V–5.5V supply range. The 24AA256T-E/SN does not support 1 MHz operation - that capability is reserved for the 24FC256 variant.

Does the 24AA256T-E/SN support hardware write protection, and how is it implemented?

Yes, the 24AA256T-E/SN implements hardware write protection via the WP (Write-Protect) pin. When WP is tied to V_CC, all write operations (byte and page) are inhibited while read operations remain fully functional. The pin state is sampled only at the Stop condition of each write command, making it immune to transient glitches during active communication. This feature is confirmed in Section 2.4 and Figure 1-1 of the DS20001203Y datasheet.

What package type does the 24AA256T-E/SN use, and are all address pins available?

The 24AA256T-E/SN uses the 8-lead SOIC (SN) package, per Microchip's Device Selection Table and Package Marking Information. All three chip address pins - A0, A1, and A2 - are fully functional and internally connected in this package, enabling up to eight devices on a single I²C bus. This contrasts with MSOP and SOT-23 variants where A0/A1 or all address pins are NC.

How many write/erase cycles can the 24AA256T-E/SN endure, and what is the basis for this rating?

The 24AA256T-E/SN is rated for more than one million (1,000,000) erase/write cycles per page, as specified in the Features section and verified in Table 1-2 (Parameter D17, TWC). This endurance applies to page-mode writes at +25°C and 5.5V, and reflects actual characterization data - not extrapolated or statistical projections. Endurance is specified per page because page writes refresh entire 64-byte blocks.

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

No, the 24AA256T-E/SN is rated for Industrial temperature range (–40°C to +85°C), not automotive. While the broader 24XX256 family includes AEC-Q100-qualified variants (e.g., 24AA256T-I/SN with 'I' suffix), the 'E' in 24AA256T-E/SN denotes Extended temperature (–40°C to +125°C) - which exceeds industrial spec but does not imply AEC-Q100 qualification. Automotive use requires explicit AEC-Q100 documentation, which is absent for this part number.