Microchip Technology AT25640A-10TU-2.7

Overview

AT25640A-10TU-2.7 from Microchip Technology (formerly Atmel) is a 64 Kbit SPI serial EEPROM organized as 8192 × 8-bit memory, operating from 2.7V to 5.5V, supporting 20 MHz clock rate at 5V, with 32-byte page write capability and hardware/software write protection via WP pin and status register. It serves as nonvolatile configuration storage in industrial controllers and embedded systems requiring low-voltage operation and high endurance.

For engineers reviewing the AT25640A-10TU-2.7 datasheet, AT25640A-10TU-2.7 pinout, AT25640A-10TU-2.7 application, or AT25640A-10TU-2.7 equivalent, key selection considerations include its TSSOP-8 package, 2.7–5.5 V supply range, 1 million write cycles, 100-year data retention, and SPI Mode 0/3 compatibility for microcontroller interfacing.

Technical Context

The AT25640A-10TU-2.7 implements a synchronous SPI slave interface with separate SI/SO lines, CS-controlled selection, and HOLD pin for pausing communication without resetting the sequence. It uses an 8-bit instruction register with MSB-first transmission and supports WREN/WRDI/RDSR/WRSR/READ/WRITE op-codes.

Block write protection is configured via BP0/BP1 bits in the status register to protect 0%, 25%, 50%, or 100% of the memory array. Hardware write protection is enabled only when WPEN = 1 and WP = low; otherwise, software control dominates. The device powers up in write-disabled state and requires explicit WREN before programming.

Key Specifications

Pinout & Package

AT25640A-10TU-2.7 is supplied in an 8-lead TSSOP package (JEDEC MO-153, 4.4 mm body width), RoHS-compliant and green-marked ("U" suffix), with 0.65 mm lead pitch and standard pin 1 indicator.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95640-DRMN6TP/K and BR24G64FJ-3GE2, the AT25640A-10TU-2.7 delivers superior timing headroom (20 MHz), lowest standby current in its voltage class, and unique HOLD functionality for deterministic SPI session management - making it optimal for industrial real-time systems.

Availability

AT25640A-10TU-2.7 is available at Aetrix Electronics and suitable for industrial PLCs, medical infusion pumps, automotive body control modules, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for AT25640A-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 acquired Atmel in 2016 and maintains full support for the AT25xxxA family of SPI EEPROMs, emphasizing reliability, longevity, and industrial-grade qualification.

The AT25640A-10TU-2.7 belongs to Microchip's serial EEPROM product line, designed specifically for robust nonvolatile storage in resource-constrained embedded systems where low-power operation, high endurance, and SPI simplicity are critical.

FAQ

What is the maximum clock frequency supported by the AT25640A-10TU-2.7?

The AT25640A-10TU-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 is reduced to 10 MHz per AC Characteristics Table 1-3. This ensures reliable setup/hold timing margins across its full 2.7–5.5 V operating range. The AT25640A-10TU-2.7 must be clocked within these limits to guarantee correct read/write behavior and avoid data corruption.

Does the AT25640A-10TU-2.7 support both SPI Mode 0 and Mode 3?

Yes, the AT25640A-10TU-2.7 explicitly supports SPI Modes 0 (CPOL = 0, CPHA = 0) and 3 (CPOL = 1, CPHA = 1), as confirmed in its Features section. Mode 0 operation is fully documented in the datasheet timing diagrams and functional description. The device functions as a slave with fixed SCK input polarity and phase alignment, enabling interoperability with common microcontrollers such as PIC, AVR, and STM32 without mode conversion logic. The AT25640A-10TU-2.7 does not support Modes 1 or 2.

How does the write protection mechanism work on the AT25640A-10TU-2.7?

The AT25640A-10TU-2.7 implements dual-layer write protection: hardware via the WP pin (when WPEN = 1 and WP = low) and software via BP0/BP1 bits in the status register. WP locks the status register and selected memory blocks; BP bits define protection granularity (0%, 25%, 50%, or 100%). The AT25640A-10TU-2.7 requires WREN before any write, and WRDI resets the latch. Protection remains active across power cycles since BP/WPEN bits are nonvolatile.

What package type is used for the AT25640A-10TU-2.7?

The AT25640A-10TU-2.7 uses an 8-lead TSSOP package (JEDEC MO-153, 4.4 mm body width), designated by the "TU" suffix in the part number. It features gull-wing leads, 0.65 mm pitch, RoHS-compliant green finish ("U"), and operates across –40°C to +85°C. This surface-mount package offers compact footprint and thermal performance suitable for dense PCB layouts in industrial and automotive applications. The AT25640A-10TU-2.7 is not offered in PDIP, SOIC, or DFN variants under this specific ordering code.

Is the AT25640A-10TU-2.7 suitable for automotive applications?

The AT25640A-10TU-2.7 is specified for industrial temperature range (–40°C to +85°C) and is available in automotive-grade versions (e.g., AT25640A-10TU-2.7A), but the standard AT25640A-10TU-2.7 is not AEC-Q100 qualified. For automotive body control or infotainment modules requiring qualification, designers should verify the specific automotive variant's documentation and test reports. The AT25640A-10TU-2.7 provides the core functionality and reliability needed in less stringent automotive subsystems, pending system-level validation.