Microchip Technology AT25256A-10TU-2.7

Overview

AT25256A-10TU-2.7 from Microchip Technology (formerly Atmel) is a 256 Kbit SPI serial EEPROM organized as 32,768 × 8 bits, operating from 2.7V to 5.5V, featuring 20 MHz max clock rate at 5V, 64-byte page write capability, and hardware/software write protection via WP and HOLD pins. It is used in industrial control systems for nonvolatile parameter storage requiring low-voltage operation and high reliability.

For engineers reviewing the AT25256A-10TU-2.7 datasheet, AT25256A-10TU-2.7 pinout, AT25256A-10TU-2.7 application, or AT25256A-10TU-2.7 equivalent, key selection criteria include VCC range (2.7–5.5 V), SPI Mode 0/3 compatibility, 1 million write endurance, >100-year data retention, and TSSOP-8 packaging with lead-free/halogen-free compliance.

Technical Context

The AT25256A-10TU-2.7 implements a synchronous serial peripheral interface (SPI) slave architecture with separate SI (input) and SO (output) lines, supporting both Mode 0 (CPOL=0, CPHA=0) and Mode 3 (CPOL=1, CPHA=1). Its instruction set includes WREN, WRDI, RDSR, WRSR, READ, and WRITE, all MSB-first with CS-driven activation.

Internal block write protection is controlled by BP1/BP0 bits in the status register, enabling protection of top 1/4, top 1/2, or entire memory array (0000–7FFFh for AT25256A). The WP pin-when enabled via WPEN bit-blocks writes to the status register and protected blocks; HOLD suspends ongoing serial transfers without resetting sequence state.

Key Specifications

Pinout & Package

AT25256A-10TU-2.7 is housed in an 8-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, with 0.65 mm lead pitch and 4.4 mm body width. Pin 1 is marked by a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95256-DW and 25AA256-I/P, AT25256A-10TU-2.7 uniquely combines TSSOP-8 packaging, integrated HOLD functionality for deterministic interrupt handling, and optimized 2.7–5.5 V operation for industrial 3.3 V systems - making it ideal for new designs prioritizing board space, robustness, and real-time responsiveness.

Availability

AT25256A-10TU-2.7 is available at Aetrix Electronics and suitable for industrial sensor calibration, smart meter firmware storage, PLC I/O module configuration, and medical device parameter backup requiring stable component supply and long-term lifecycle support.

Supply support for AT25256A-10TU-2.7 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 a focus on embedded control and connectivity.

The AT25256A-10TU-2.7 belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power nonvolatile data storage in industrial, commercial, and medical equipment where SPI interface simplicity and long-term data integrity are critical.

FAQ

What is the maximum SPI clock frequency supported by the AT25256A-10TU-2.7?

The AT25256A-10TU-2.7 supports up to 20 MHz SCK frequency when VCC = 5.0 V. At lower supply voltages (e.g., 2.7 V), the maximum clock rate reduces to 10 MHz per AC Characteristics Table 1-3. This ensures timing margin across voltage and temperature ranges while maintaining compatibility with common microcontroller SPI peripherals.

Does the AT25256A-10TU-2.7 require a separate erase command before writing?

No, the AT25256A-10TU-2.7 does not require a separate erase command. All write operations - whether byte or 64-byte page - are self-timed and automatically erase and program the target location. A Write Enable (WREN) instruction must precede any write, and the device returns to write-disable state after each internal write cycle completes.

How does the HOLD pin function during an active SPI transaction on the AT25256A-10TU-2.7?

When the HOLD pin is pulled low while SCK is low during an active SPI transaction, the AT25256A-10TU-2.7 suspends communication without resetting the internal address or instruction state. SI inputs are ignored and SO enters high-impedance. Resuming requires bringing HOLD high while SCK remains low - then normal transfer continues from the exact bit position where it paused.

Can the AT25256A-10TU-2.7 be used in a 1.8 V system?

No, the AT25256A-10TU-2.7 is specified for 2.7 V to 5.5 V operation only. For 1.8 V systems, Microchip offers the AT25256A-10TU-1.8 variant, which shares identical pinout and functionality but is characterized down to 1.8 V. Using AT25256A-10TU-2.7 below 2.7 V may result in unreliable read/write behavior or failure to respond to commands.

What memory protection options are available on the AT25256A-10TU-2.7?

The AT25256A-10TU-2.7 provides three levels of block write protection via BP1/BP0 bits in its status register: none, top 1/4 (6000–7FFFh), top 1/2 (4000–7FFFh), or full array (0000–7FFFh). Protection is enforced alongside hardware write disable via the WP pin (when WPEN = 1) and software write disable via WRDI instruction - offering layered security against unintended writes.