Microchip Technology AT25256AN-10SI-1.8

Overview

AT25256AN-10SI-1.8 from Microchip Technology (formerly Atmel) is a 256 Kbit SPI serial EEPROM organized as 32,768 × 8 bits, operating from 1.8 V to 5.5 V, supporting 20 MHz clock rate at 5 V, featuring hardware write protection via WP pin and HOLD suspend functionality, and used in industrial control modules for nonvolatile parameter storage.

For engineers reviewing the AT25256AN-10SI-1.8 datasheet, AT25256AN-10SI-1.8 pinout, AT25256AN-10SI-1.8 application, or AT25256AN-10SI-1.8 equivalent, this page delivers verified electrical specs, JEDEC SOIC-8 package details, SPI Mode 0/3 compatibility, block write protection levels, and real-world design implications for low-voltage embedded systems.

Technical Context

The AT25256AN-10SI-1.8 implements a synchronous SPI slave interface with separate SI/SO pins, MSB-first data framing, and op-code–driven command execution (WREN, WRITE, RDSR, WRSR). It requires CS low to initiate communication and supports HOLD suspension without sequence reset.

Its internal architecture includes an 8-bit instruction register, nonvolatile status register (WPEN, BP1/BP0, WEN, RDY), and automatic address incrementing during 64-byte page writes. Block protection is implemented via BP0/BP1 bits controlling top 1/4, 1/2, or full array lock, independent of WP pin state when WPEN = 0.

Key Specifications

Pinout & Package

AT25256AN-10SI-1.8 is housed in an 8-lead JEDEC SOIC package (8S1), 0.150" wide body, with gull-wing leads and standard 1.27 mm pitch. Pin 1 is marked by a notch or dot; device orientation follows JEDEC MO-001AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95256-DWDW and BR25L256FJ-WE2, AT25256AN-10SI-1.8 uniquely combines HOLD functionality, 100K write endurance, and guaranteed 1.8 V operation with full AC timing - making it optimal for industrial controllers needing robust interrupt handling and long-term field reliability.

Availability

AT25256AN-10SI-1.8 is available at Aetrix Electronics and suitable for industrial PLCs, automotive BCMs, smart energy meters, and medical infusion pumps requiring stable component supply across extended product lifecycles.

Supply support for AT25256AN-10SI-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 acquired Atmel in 2016 and maintains full technical and manufacturing continuity for the AT25xxx EEPROM family, delivering high-reliability nonvolatile memory solutions since 1980.

The AT25xxx series was designed specifically for embedded systems requiring SPI-compatible, low-voltage, high-endurance EEPROM with flexible hardware/software write protection - targeting industrial, automotive, and medical applications demanding data integrity over decades.

FAQ

What voltage range does the AT25256AN-10SI-1.8 support, and how does it affect timing?

The AT25256AN-10SI-1.8 operates from 1.8 V to 5.5 V. At 5.0 V, it supports up to 20 MHz SCK; at 2.7 V, max clock drops to 10 MHz; and at 1.8 V, it is rated for 5 MHz. These deratings are defined in the AC Characteristics table and directly impact read/write throughput - for example, a 64-byte page write takes ~3.2 ms at 20 MHz but ~6.4 ms at 10 MHz. AT25256AN-10SI-1.8 maintains full functionality across this range without external level shifters.

How does the HOLD pin function during an active SPI transaction on the AT25256AN-10SI-1.8?

The HOLD pin on the AT25256AN-10SI-1.8 suspends serial communication without resetting the internal address counter or command state. To activate, HOLD must be driven low while SCK is low; to resume, HOLD is returned high while SCK remains low. During HOLD, SI inputs are ignored and SO enters high-impedance. This allows the host MCU to service interrupts and return seamlessly - a feature absent in many competing EEPROMs. AT25256AN-10SI-1.8 guarantees hold timing (tHD, tCD) down to 1.8 V.

Can the AT25256AN-10SI-1.8 be used in automotive applications, and what qualifications does it meet?

Yes - the AT25256AN-10SI-1.8 is qualified for Industrial Temperature (−40°C to +85°C), and Microchip offers automotive-grade variants (e.g., AT25256A-10SE-2.7) with Extended Temperature (−40°C to +125°C) and AEC-Q100 stress testing. While AT25256AN-10SI-1.8 itself is not AEC-Q100 certified, its construction, 100K endurance, and >100-year retention make it widely deployed in non-safety-critical automotive subsystems like body control modules. Always verify qualification status for specific AT25256AN-10SI-1.8 lot markings.

What happens if a WRITE command is issued to a block-protected address range on the AT25256AN-10SI-1.8?

If the AT25256AN-10SI-1.8's status register has BP1/BP0 set to protect any memory region (e.g., BP1=1, BP0=1 locks 0x0000–0x7FFF), and a WRITE instruction targets an address within that range, the device ignores the data and completes the cycle without error. No status flag is set, and RDY returns to 0 immediately. The protected area remains unmodified - this silent fail-safe behavior prevents corruption of critical firmware or calibration data. AT25256AN-10SI-1.8 enforces this at the silicon level.

Is the AT25256AN-10SI-1.8 pin-compatible with other members of the AT25xxx family, such as the AT25128A?

Yes - AT25256AN-10SI-1.8 shares identical pinout, package (JEDEC SOIC-8), and SPI interface protocol with AT25128A-10SI-1.8 and AT25080A-10SI-1.8. The only functional difference is memory density: AT25128A is 128 Kbit (16K × 8), while AT25256AN-10SI-1.8 is 256 Kbit (32K × 8). Address bits A14–A0 are used (vs. A13–A0 for AT25128A), but pin-for-pin layout and timing specs remain fully compatible - enabling drop-in upgrades in existing designs with minor firmware address-map adjustments.