Microchip Technology AT25040A-10PU-1.8

Overview

AT25040A-10PU-1.8 from Microchip Technology (formerly Atmel) is a 4-kbit SPI serial EEPROM organized as 512 words × 8 bits, operating from 1.8 V to 5.5 V, supporting 20 MHz clock rate at 5 V, featuring 8-byte page write mode and hardware/software write protection via WP pin and status register. It is used in industrial sensor calibration storage, embedded system configuration retention, and power-meter firmware parameter backup.

For engineers reviewing the AT25040A-10PU-1.8 datasheet, AT25040A-10PU-1.8 pinout, AT25040A-10PU-1.8 application, or AT25040A-10PU-1.8 equivalent, key selection criteria include low-voltage 1.8 V operation, 1 million write endurance, 100-year data retention, SPI Mode 0/3 compatibility, and 8-lead PDIP package with CS/SCK/SI/SO/WP/HOLD interface signals.

Technical Context

The AT25040A-10PU-1.8 implements a synchronous SPI slave interface with separate SI (input) and SO (output) pins, MSB-first data framing, and op-code–driven command set including WREN, WRITE, READ, RDSR, and WRSR. It uses an internal address counter that auto-increments during sequential reads and wraps on boundary overflow.

Block write protection is controlled nonvolatilely via BP1/BP0 bits in the status register, enabling protection of 0%, 25%, 50%, or 100% of the 512-word array. The HOLD pin suspends ongoing serial transfers without resetting the sequence, while the WP pin provides hardware-level write inhibition independent of software state.

Key Specifications

Pinout & Package

AT25040A-10PU-1.8 is supplied in an 8-lead JEDEC PDIP package (package code 8P3), 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 M95040-DRMN6TP/K and BR24G04FJ-WE2, the AT25040A-10PU-1.8 offers through-hole PDIP packaging for prototyping and repair, native SPI Mode 0/3 compatibility with legacy controllers, and dedicated HOLD functionality for deterministic interrupt handling-making it optimal for industrial control and automotive body electronics where robustness and interface flexibility are critical.

Availability

AT25040A-10PU-1.8 is available at Aetrix Electronics and suitable for industrial sensor calibration, smart energy metering, and automotive body control unit designs requiring stable component supply, long-lifecycle assurance, and RoHS-compliant through-hole packaging.

Supply support for AT25040A-10PU-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 is a global semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with broad industrial and automotive qualification capabilities.

The AT25040A-10PU-1.8 belongs to Microchip's legacy serial EEPROM product line, designed specifically for reliable, low-voltage nonvolatile data storage in resource-constrained embedded systems where SPI interface simplicity and long-term data integrity are essential.

FAQ

What voltage range does the AT25040A-10PU-1.8 support, and how does it affect interface compatibility?

The AT25040A-10PU-1.8 operates from 1.8 V to 5.5 V, making it compatible with both 1.8 V logic families and legacy 5 V microcontrollers. Its input thresholds scale with VCC (VIH ≥ 0.7×VCC), ensuring robust signal recognition across the full range. This eliminates level-shifting requirements in mixed-voltage systems and simplifies design reuse across multiple generations of host processors. The AT25040A-10PU-1.8 maintains full AC timing compliance-including 20 MHz operation at 5 V-within this range.

How does the HOLD pin function in the AT25040A-10PU-1.8, and what is its timing requirement?

The HOLD pin in the AT25040A-10PU-1.8 suspends ongoing SPI communication without resetting the internal address counter or command state. To activate HOLD, the pin must be driven low while SCK is low; to resume, it must be returned high while SCK remains low. During HOLD, SI is ignored and SO enters high-impedance. This allows time-critical MCU interrupts to execute without corrupting EEPROM transactions. The AT25040A-10PU-1.8 specifies tHD (HOLD setup) and tCD (HOLD hold) times of 20–80 ns depending on VCC.

Can the AT25040A-10PU-1.8 be used as a direct replacement for the AT25040A-10PU-2.7 in existing designs?

Yes, the AT25040A-10PU-1.8 is pin-compatible and functionally identical to the AT25040A-10PU-2.7 except for extended 1.8 V minimum supply support. Both share identical PDIP-8 packaging, SPI command set, timing, and protection features. The AT25040A-10PU-1.8 adds guaranteed operation down to 1.8 V, enabling deployment in newer ultra-low-power systems without hardware changes. No firmware or layout modifications are needed when upgrading from -2.7 to -1.8 variants.

What is the maximum write endurance and data retention specification for the AT25040A-10PU-1.8?

The AT25040A-10PU-1.8 guarantees 1,000,000 write/erase cycles and 100 years of data retention at +25 °C. Endurance is tested under worst-case conditions (5.5 V, 85 °C, page-mode writes), and retention is characterized using accelerated high-temperature testing with extrapolation. These specifications apply to the full 512-word memory array and are maintained across the rated temperature range (−40 °C to +85 °C). The AT25040A-10PU-1.8 meets industrial longevity requirements for firmware parameter storage and calibration data archiving.

Does the AT25040A-10PU-1.8 support SPI Mode 3, and how is it configured?

Yes, the AT25040A-10PU-1.8 explicitly supports SPI Modes 0 (CPOL = 0, CPHA = 0) and 3 (CPOL = 1, CPHA = 1), as confirmed in its official datasheet. Mode selection is determined solely by the host controller's SCK polarity and phase settings; no internal register configuration is required. In Mode 3, data is sampled on the SCK falling edge and shifted out on the rising edge. The AT25040A-10PU-1.8 maintains identical timing parameters (tWH, tWL, tSU, tH) across both modes, ensuring interoperability with diverse SPI masters including Freescale Kinetis and STMicro STM32 families.