Microchip Technology AT25640N-10SC-2.7

Overview

AT25640N-10SC-2.7 from Atmel is a 64 Kbit (8192 × 8) SPI serial EEPROM optimized for low-voltage embedded systems, supporting V_CC = 2.7V to 5.5V, 3.0 MHz clock rate at 5V, 32-byte page write mode, and block write protection covering 1/4, 1/2, or entire memory array. It operates in SPI Modes 0 and 3 and features hardware/software data protection via WP pin and Write Disable instruction.

For engineers reviewing the AT25640N-10SC-2.7 datasheet, AT25640N-10SC-2.7 pinout, AT25640N-10SC-2.7 application, or AT25640N-10SC-2.7 equivalent, key selection criteria include its 2.7–5.5V supply range, 10 ms max write cycle time, 1 million endurance cycles, 100-year data retention, and JEDEC SOIC-8 package compatibility with industrial temperature support.

Technical Context

The AT25640N-10SC-2.7 implements a synchronous SPI slave interface with separate SI (input) and SO (output) pins, MSB-first data transfer, and chip-select–driven command sequencing. Its internal architecture includes an 8-bit instruction register, nonvolatile status register (WPEN, BP1/BP0, WEN, RDY), and automatic address incrementing during page writes.

It supports three voltage operating ranges (1.8V, 2.7V, and 5.0V), with corresponding AC timing constraints: t_WC = 10 ms max at 2.7–5.5V, f_SCK = 2.1 MHz max in that range, and t_WH/t_WL ≥ 200 ns. Block protection is implemented via status register bits BP1/BP0, enabling selective locking of memory segments without external logic.

Key Specifications

Pinout & Package

AT25640N-10SC-2.7 uses an 8-lead JEDEC SOIC package (8S1), 0.150" wide, with standard gull-wing leads and 1.27 mm pitch. Pin 1 is marked by a notch or dot; device is lead-free and RoHS-compliant.

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/SN, AT25640N-10SC-2.7 delivers proven industrial-grade reliability at lower cost, with deterministic 10 ms write timing and straightforward WP/HOLD implementation-ideal for cost-sensitive, thermally stable embedded systems where 2.1 MHz SPI bandwidth suffices.

Availability

AT25640N-10SC-2.7 is available at Aetrix Electronics and suitable for industrial PLC configuration storage, medical device calibration data retention, and automotive body control module settings requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for AT25640N-10SC-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

Atmel Corporation (now part of Microchip Technology) is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and security ICs for industrial, automotive, and consumer applications.

The AT25xxx family was designed specifically for robust, low-power serial EEPROM replacement in embedded systems requiring SPI interface compatibility, flexible voltage operation, and high endurance-targeting applications where flash wear-leveling overhead is unacceptable.

FAQ

What voltage range does the AT25640N-10SC-2.7 support, and how does it affect system design?

The AT25640N-10SC-2.7 supports 2.7V to 5.5V operation, enabling direct integration with both 3.3V and 5V microcontrollers without level-shifting circuitry. This simplifies power domain partitioning and reduces BOM count. The device maintains full SPI functionality-including 2.1 MHz clock rate and 10 ms write cycle-across the entire range, ensuring consistent timing behavior regardless of rail voltage. Designers must still place a 0.1 µF ceramic decoupling capacitor near V_CC to suppress switching noise during write operations.

How does the block write protection feature work on the AT25640N-10SC-2.7?

The AT25640N-10SC-2.7 implements block write protection via two nonvolatile status register bits (BP1 and BP0), which define four protection levels: none, 1/4 array (upper 2 KB), 1/2 array (upper 4 KB), or full array (all 8 KB). Protection is enforced at the hardware level-writes to locked addresses are ignored-and can be configured only after issuing WREN and WRSR commands. When WPEN = 1 and WP pin is low, even the status register becomes write-protected, preventing accidental reconfiguration.

Can the AT25640N-10SC-2.7 be used in SPI Mode 1 or Mode 2, or is it limited to Modes 0 and 3?

The AT25640N-10SC-2.7 is explicitly specified for SPI Modes 0 (CPOL = 0, CPHA = 0) and 3 (CPOL = 1, CPHA = 1) only. It does not support Mode 1 (CPOL = 0, CPHA = 1) or Mode 2 (CPOL = 1, CPHA = 0), as confirmed by the "Supports SPI Modes 0 (0,0) and 3 (1,1)" feature statement and timing diagrams showing sampling on SCK rising edge for Mode 0 and falling edge for Mode 3. Attempting Mode 1 or 2 will result in misaligned data capture and communication failure.

What is the maximum write endurance and data retention specification for the AT25640N-10SC-2.7?

The AT25640N-10SC-2.7 guarantees 1 million write cycles per memory location and 100 years of data retention at +25°C, as stated in the Features section and validated across the commercial and industrial temperature ranges. These specifications apply to both byte and page write operations and are measured under standard conditions (V_CC = 5.0V, T_A = 25°C). Retention degrades logarithmically with temperature; at +85°C, expected retention remains >10 years per JEDEC JESD22-A117 stress testing methodology.

Does the AT25640N-10SC-2.7 require an external erase command before writing new data?

No, the AT25640N-10SC-2.7 does not require a separate erase command. All programming cycles are self-timed and automatically erase the target byte or page prior to writing new data. The device handles this internally-only WREN followed by WRITE (with address and data) is needed. This eliminates firmware complexity associated with erase/write sequencing and avoids partial-write failures common in flash-based alternatives.