Microchip Technology AT25256A-10PU-2.7

Overview

AT25256A-10PU-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 status register. It serves as nonvolatile data storage in industrial control modules requiring low-voltage operation and robust data retention.

For engineers reviewing the AT25256A-10PU-2.7 datasheet, AT25256A-10PU-2.7 pinout, AT25256A-10PU-2.7 application, or AT25256A-10PU-2.7 equivalent, key selection criteria include VCC range compatibility (2.7–5.5 V), SPI Mode 0/3 support, 1 million write endurance, >100-year data retention, and 8-lead PDIP package with CS/SO/WP/GND/VCC/HOLD/SCK/SI pin configuration.

Technical Context

The AT25256A-10PU-2.7 operates exclusively as an SPI slave device with separate SI (input) and SO (output) pins, supporting only SPI Modes 0 (CPOL=0, CPHA=0) and 3 (CPOL=1, CPHA=1). Its instruction set includes WREN, WRDI, RDSR, WRSR, READ, and WRITE - all MSB-first, initiated by CS falling edge.

Block write protection is implemented via nonvolatile BP1/BP0 bits in the status register, enabling protection of top 1/4 (6000–7FFFh), top 1/2 (4000–7FFFh), or entire memory array (0000–7FFFh) of the AT25256A. The WP pin provides hardware-level inhibition of status register writes when WPEN=1 and WP=low, while HOLD suspends ongoing serial transfers without resetting sequence state.

Key Specifications

Pinout & Package

AT25256A-10PU-2.7 is housed in an 8-lead PDIP (Plastic Dual In-line Package), 0.300" wide body, RoHS-compliant and lead-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25256A-10PU-2.7, M95256-DW offers automotive qualification at higher temperature but identical pinout and command set, while BR25H256FJ-2CE2 trades speed for ECC-based reliability - making AT25256A-10PU-2.7 optimal for cost-sensitive industrial applications needing 20 MHz performance and proven 1M-cycle endurance.

Availability

AT25256A-10PU-2.7 is available at Aetrix Electronics and suitable for industrial PLCs, medical infusion pumps, and smart energy meters requiring stable component supply, long-life data retention, and RoHS-compliant packaging.

Supply support for AT25256A-10PU-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 nonvolatile memory solutions, with broad industrial and automotive product portfolios.

The AT25256A-10PU-2.7 belongs to Microchip's legacy Atmel SPI EEPROM family, designed specifically for reliable, low-power, byte-addressable nonvolatile storage in space-constrained embedded systems interfacing directly with SPI-capable MCUs.

FAQ

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

The AT25256A-10PU-2.7 supports up to 20 MHz SCK frequency when operated at 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. This ensures timing margin compliance across its full 2.7–5.5 V operating range. The AT25256A-10PU-2.7 must be configured for SPI Mode 0 or 3 to maintain valid setup/hold times.

Does the AT25256A-10PU-2.7 support hardware write protection independent of software commands?

Yes - the AT25256A-10PU-2.7 implements dual-layer write protection. The WP pin provides hardware-level inhibition of status register writes when WPEN = 1 and WP = low. This protection remains active even if software disables write enable (WRDI), ensuring critical configuration bits cannot be altered during unexpected MCU resets or firmware faults. The AT25256A-10PU-2.7 retains this behavior across power cycles.

Can the AT25256A-10PU-2.7 be used in systems powered by 3.3 V logic?

Yes - the AT25256A-10PU-2.7 is fully compatible with 3.3 V systems. Its 2.7–5.5 V supply range includes standard 3.3 V rails, and its input thresholds (VIH ≥ 0.7×VCC, VIL ≤ 0.3×VCC) ensure reliable recognition of 3.3 V logic levels. Output VOH/VOL specs guarantee interoperability with common 3.3 V MCUs without level shifters. The AT25256A-10PU-2.7 delivers 10 MHz max clock rate at 3.3 V per datasheet AC table.

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

The HOLD pin on the AT25256A-10PU-2.7 suspends serial communication without resetting the internal address counter or command state. When asserted low while SCK is low, it places SO in high-impedance and ignores SI inputs until HOLD returns high (also during SCK low). This allows the host MCU to service higher-priority interrupts mid-transfer. The AT25256A-10PU-2.7 resumes exactly where it left off - preserving read/write sequence integrity.

What package type is used for the AT25256A-10PU-2.7, and is it RoHS-compliant?

The AT25256A-10PU-2.7 uses an 8-lead PDIP (Plastic Dual In-line Package), 0.300" wide body, designated as package code "8P3". It is lead-free and halogen-free, meeting RoHS Directive 2011/65/EU requirements. The "U" suffix in the part number explicitly denotes green packaging compliance. The AT25256A-10PU-2.7 is rated for industrial temperature range (−40°C to +85°C) and features matte tin lead finish.