Microchip Technology AT24C256-10TU-1.8

Overview

AT24C256-10TU-1.8 from Microchip Technology (formerly Atmel) is a 256 Kbit (32,768 × 8) two-wire serial EEPROM optimized for low-voltage embedded systems. It operates from 1.8 V to 3.6 V, supports 100 kHz I²C bus speed at 1.8 V, features hardware write protection via the WP pin, and delivers 1 million write cycles with 40-year data retention. It is used in industrial sensor calibration storage and power-meter firmware parameter backup.

For engineers reviewing the AT24C256-10TU-1.8 datasheet, AT24C256-10TU-1.8 pinout, AT24C256-10TU-1.8 application, or AT24C256-10TU-1.8 equivalent, key selection considerations include 1.8 V operation margin, 64-byte page write capability, TSSOP-8 package footprint, and compatibility with legacy I²C controllers requiring 100 kHz timing compliance.

Technical Context

The AT24C256-10TU-1.8 implements a standard two-wire (I²C-compatible) interface with open-drain SDA and Schmitt-triggered SCL inputs for noise immunity. Its internal architecture organizes memory as 512 pages of 64 bytes each, enabling partial-page writes without address rollover beyond page boundaries.

Device addressing uses A0 and A1 pins to support up to four devices on a shared bus; the WP pin provides hardware-level write inhibition when tied to VCC. The part complies with I²C protocol timing requirements at 1.8 V, including tLOW ≥ 4.7 µs and tHIGH ≥ 4.0 µs, and incorporates acknowledge polling for write-cycle completion detection.

Key Specifications

Pinout & Package

AT24C256-10TU-1.8 is supplied in an 8-lead Plastic Thin Shrink Small Outline Package (TSSOP), 4.4 mm body width, RoHS-compliant and halogen-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C256B-10TU-1.8 and M24256-BWMN6TP, the AT24C256-10TU-1.8 offers proven industrial-temperature reliability at lower cost but lacks extended-temp qualification and high-speed 1.8 V timing - making it optimal for cost-sensitive, ambient-controlled applications where 100 kHz suffices.

Availability

AT24C256-10TU-1.8 is available at Aetrix Electronics and suitable for smart metering, industrial PLC configuration storage, and medical sensor calibration requiring stable component supply and long-term obsolescence management.

Supply support for AT24C256-10TU-1.8 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 is a global semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with broad industrial and automotive qualification coverage.

The AT24C256-10TU-1.8 belongs to Microchip's legacy AT24Cxx serial EEPROM product line, designed for reliable, low-voltage nonvolatile data storage in space-constrained embedded systems.

FAQ

What is the maximum I²C clock frequency supported by AT24C256-10TU-1.8 at 1.8 V?

The AT24C256-10TU-1.8 supports a maximum I²C clock frequency of 100 kHz when operating at 1.8 V. This is specified in Table 4 (AC Characteristics – Industrial Temperatures) of the datasheet and reflects timing margins required for reliable communication under low-voltage conditions. Exceeding this frequency may result in setup/hold violations and data corruption. The AT24C256-10TU-1.8 does not guarantee 400 kHz operation at 1.8 V - that speed is only validated for 2.5 V and 5.0 V supply conditions.

Does AT24C256-10TU-1.8 support page write operations, and what is the page size?

Yes, the AT24C256-10TU-1.8 supports 64-byte page write operations, as confirmed in the Features section and Device Operation chapter. Each page consists of 64 contiguous bytes, and the internal address counter wraps within the page boundary - meaning writing beyond byte 63 rolls over to byte 0 of the same page. This capability allows efficient bulk writes without requiring individual byte-addressed transactions, reducing I²C bus utilization and firmware overhead. The AT24C256-10TU-1.8 also permits partial page writes (e.g., 12 bytes), preserving unmodified data in the remainder of the page.

How does the Write Protect (WP) pin function on AT24C256-10TU-1.8?

The WP pin on AT24C256-10TU-1.8 is an active-high hardware write protection input. When WP is tied to VCC, all write operations (byte and page) to the memory array are inhibited, though reads remain fully functional. When WP is tied to GND, normal write operations are enabled. If left floating, the pin is internally pulled down to GND under low-capacitance conditions (<3 pF), but Microchip recommends explicit grounding for robustness. This feature prevents accidental overwrites during power-up, brown-out, or software faults - a critical safeguard in AT24C256-10TU-1.8 deployments like energy meter firmware storage.

What package type is used for AT24C256-10TU-1.8, and what are its key mechanical dimensions?

The AT24C256-10TU-1.8 uses an 8-lead Plastic Thin Shrink Small Outline Package (TSSOP), designated as 8A2 in Microchip's ordering nomenclature. Its body measures 3.00 mm × 4.40 mm, with a maximum height of 1.20 mm and lead pitch of 0.65 mm. Pin 1 is marked by a notch or beveled corner on the top surface. This package is RoHS-compliant and halogen-free ("U" suffix), and its compact footprint supports high-density PCB layouts in space-constrained applications such as portable medical devices and smart meters where the AT24C256-10TU-1.8 is commonly deployed.

Is AT24C256-10TU-1.8 recommended for new designs, and what is the suggested migration path?

No - the AT24C256-10TU-1.8 is explicitly marked "Not recommended for new design" in Microchip's official documentation (Revision History, page 22). The recommended migration path is the AT24C256B-10TU-1.8, which shares identical pinout, voltage range, and package but adds extended temperature qualification (–40°C to +125°C) and enhanced endurance validation. While AT24C256-10TU-1.8 remains available for legacy support and existing production, new designs should adopt the AT24C256B-10TU-1.8 to ensure long-term supply continuity and broader environmental compliance. Both parts maintain full software and hardware compatibility.