Microchip Technology AT25640-10PC

Overview

AT25640-10PC from Atmel is a 64 Kbit (8192 × 8) SPI serial EEPROM with 2.7–5.5 V operation, 3 MHz max clock rate at 5 V, 32-byte page write capability, and hardware/software write protection via WP pin and status register. It delivers high reliability with 1 million write cycles and 100-year data retention, deployed in industrial control panels requiring nonvolatile parameter storage.

For engineers reviewing the AT25640-10PC datasheet, AT25640-10PC pinout, AT25640-10PC application, or AT25640-10PC equivalent, key selection criteria include low-voltage compatibility (2.7 V min), block write protection granularity (1/4, 1/2, or full array), self-timed 5 ms typical write cycle, and PDIP-8 package suitability for through-hole prototyping and legacy industrial PCBs.

Technical Context

The AT25640-10PC operates as a SPI slave device using a 3-wire interface (CS, SCK, SI/SO) and supports SPI modes 0 and 3. Its instruction set includes WREN/WRDI for write enable/disable, RDSR/WRSR for status register access, and READ/WRITE for memory operations - all MSB-first with CS falling-edge initiation.

It implements nonvolatile block protection bits (BP1/BP0) and WPEN in the status register to configure 1/4-, 1/2-, or full-array write lock; hardware protection engages when WP is low and WPEN = 1. The HOLD pin suspends ongoing transfers without resetting the sequence, enabling multi-device arbitration on shared buses.

Key Specifications

Pinout & Package

AT25640-10PC is packaged in an 8-pin PDIP (0.300" wide, JEDEC MS-001 BA), suitable for breadboarding, socket-based testing, and industrial control boards where thermal robustness and mechanical stability are prioritized over footprint density.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95640-DW and 25AA640A-I/P, the AT25640-10PC offers proven industrial PDIP compatibility and HOLD pin support for bus arbitration, while trading off maximum clock speed for broader legacy-system integration and lower cost in commercial-temperature applications.

Availability

AT25640-10PC is available at Aetrix Electronics and suitable for industrial control panels, medical calibration modules, and point-of-sale terminals requiring stable component supply, long-term obsolescence management, and through-hole assembly compatibility.

Supply support for AT25640-10PC 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

Atmel Corporation (now part of Microchip Technology) is a semiconductor innovator specializing in microcontrollers, nonvolatile memory, and secure authentication ICs for embedded systems.

The AT25xxx family was designed specifically for SPI-based nonvolatile data storage in resource-constrained embedded applications, emphasizing low-voltage operation, robust write protection, and industrial-grade reliability.

FAQ

What is the memory organization of the AT25640-10PC?

The AT25640-10PC contains 64 Kbit of serial EEPROM organized as 8192 words × 8 bits. This structure supports byte-level random reads and writes, with 32-byte page write capability to optimize sequential programming efficiency. The memory map uses A12–A0 addressing, allowing full 13-bit access across the entire array.

Does the AT25640-10PC support 3.3 V microcontrollers?

Yes, the AT25640-10PC explicitly supports 2.7 V to 5.5 V operation, making it fully compatible with standard 3.3 V logic interfaces. Its VIH and VIL thresholds scale with VCC, and DC/AC characteristics are specified down to 2.7 V - confirmed by the "-2.7" suffix in the ordering variant AT25640-10PC-2.7.

How does write protection work on the AT25640-10PC?

Write protection on the AT25640-10PC combines hardware (WP pin) and software (status register BP0/BP1 bits). When WP is low and WPEN = 1, status register writes are blocked. BP0/BP1 define protected memory segments (none, 1/4, 1/2, or full array), and these bits are nonvolatile - retaining protection state across power cycles.

What is the purpose of the HOLD pin on the AT25640-10PC?

The HOLD pin on the AT25640-10PC suspends ongoing SPI communication without resetting the internal address counter or command state. When asserted low (with SCK low), it places SO in high-impedance and ignores SI inputs, enabling safe bus sharing - for example, allowing a second peripheral to use the same SCK/MOSI lines mid-transfer.

Is the AT25640-10PC RoHS compliant and lead-free?

Yes, the AT25640-10PC complies with RoHS Directive 2011/65/EU and is manufactured with lead-free terminations. Per Atmel documentation (Rev. 0675F), all packages - including the 8P3 PDIP variant - meet JEDEC J-STD-020 moisture sensitivity and Pb-free reflow profile requirements.