Microchip Technology AT25640N-10SC-1.8

Overview

AT25640N-10SC-1.8 from Atmel (now Microchip) is a 64 Kbit SPI serial EEPROM organized as 8192 × 8-bit memory, supporting 1.8V to 3.6V operation, 32-byte page write mode, and hardware/software write protection via WP pin and status register. It delivers 5 ms typical self-timed write cycles and is used in low-power embedded systems requiring nonvolatile parameter storage.

For engineers reviewing the AT25640N-10SC-1.8 datasheet, AT25640N-10SC-1.8 pinout, AT25640N-10SC-1.8 application, or AT25640N-10SC-1.8 equivalent, key selection criteria include 1.8V supply compatibility, SPI Mode 0/3 support, block write protection granularity (1/4, 1/2, full array), endurance of 1 million write cycles, and JEDEC SOIC-8 packaging for space-constrained PCBs.

Technical Context

The AT25640N-10SC-1.8 operates as an SPI slave device with separate SI (input) and SO (output) pins, MSB-first data framing, and chip-select–driven command sequencing. Its instruction set includes WREN, WRDI, RDSR, WRSR, READ, and WRITE, all initiated after CS low transition.

It implements dual-layer data protection: software-configurable block write protection (BP0/BP1 bits) defining protected address ranges, and hardware-based WP pin control enabled only when WPEN bit is set. The HOLD pin suspends ongoing serial transfers without resetting the sequence, preserving address continuity across pause/resume.

Key Specifications

Pinout & Package

AT25640N-10SC-1.8 is packaged in an 8-lead JEDEC SOIC (8S1), 0.150" wide, surface-mount package with standard gull-wing leads and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95640-DWDW3TP/K and BR24G64FJ-WE2, AT25640N-10SC-1.8 uniquely combines SPI Mode 0/3 flexibility, dedicated HOLD functionality for robust multi-tasking, and hardware-enforced write protection - making it optimal for real-time embedded systems where deterministic timing and fail-safe data integrity are mandatory.

Availability

AT25640N-10SC-1.8 is available at Aetrix Electronics and suitable for industrial sensor nodes, medical wearables, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed 1.8V operation.

Supply support for AT25640N-10SC-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 (formerly Atmel) is a global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and consumer markets.

The AT25640N-10SC-1.8 belongs to Microchip's legacy AT25 SPI EEPROM product line, engineered specifically for low-voltage, low-power embedded systems needing reliable, pin-compatible serial memory with flexible protection schemes.

FAQ

What voltage range does the AT25640N-10SC-1.8 support, and how does it affect timing?

The AT25640N-10SC-1.8 supports 1.8V to 3.6V operation. At 1.8V, its maximum SCK frequency is 0.5 MHz, with AC timing parameters such as tWH/tWL ≥800 ns and tSU/tH ≥100 ns. These relaxed timing margins ensure robust communication in ultra-low-power systems without requiring external clock dividers or timing adjustments.

Does the AT25640N-10SC-1.8 support both SPI Mode 0 and Mode 3, and how is mode selection handled?

Yes, the AT25640N-10SC-1.8 supports SPI Modes 0 (CPOL=0, CPHA=0) and 3 (CPOL=1, CPHA=1). Mode selection is determined entirely by the host controller's clock polarity and phase configuration - the AT25640N-10SC-1.8 has no internal mode register or configuration bits; it responds correctly to either mode per its datasheet timing diagrams.

How does the WRITE PROTECT (WP) pin function on the AT25640N-10SC-1.8, and what conditions must be met for it to take effect?

The WP pin on the AT25640N-10SC-1.8 protects the status register only when the WPEN bit is set to "1". If WPEN=0, the WP pin is ignored. When WPEN=1 and WP is driven low, all writes to the status register (including BP0/BP1 and WPEN itself) are blocked - preventing accidental changes to memory protection settings during system operation.

What is the purpose of the HOLD pin on the AT25640N-10SC-1.8, and how does it interact with ongoing SPI transactions?

The HOLD pin on the AT25640N-10SC-1.8 suspends serial 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. Resuming requires bringing HOLD high while SCK remains low - allowing seamless continuation of multi-byte reads or writes after CPU interrupts or bus arbitration.

Can the AT25640N-10SC-1.8 be used in automotive applications, and what temperature grades are available?

The AT25640N-10SC-1.8 is rated for commercial temperature range (0°C to +70°C). For automotive use, Microchip offers the industrial-grade variant AT25640N-10SI-1.8 (−40°C to +85°C), which shares identical electrical specs and pinout. Always verify qualification status per AEC-Q100 requirements when deploying in automotive ECUs.