Microchip Technology AT25040AN-10SI-2.7

Overview

AT25040AN-10SI-2.7 from Microchip Technology (formerly Atmel) is a 4-kbit SPI serial EEPROM organized as 512 words × 8 bits, operating from 2.7V to 5.5V with 20 MHz max clock rate at 5V, 8-byte page write capability, and hardware/software write protection-used for nonvolatile parameter storage in industrial microcontroller systems.

For engineers reviewing the AT25040AN-10SI-2.7 datasheet, AT25040AN-10SI-2.7 pinout, AT25040AN-10SI-2.7 application, or AT25040AN-10SI-2.7 equivalent, key selection criteria include VCC range compatibility (2.7–5.5V), 8-lead SOIC package footprint, SPI Mode 0/3 timing compliance, 1 million write endurance, and block-level write protection via status register BP0/BP1 bits.

Technical Context

The AT25040AN-10SI-2.7 implements a synchronous serial peripheral interface (SPI) slave architecture with separate SI/SO pins, MSB-first data transfer, and chip-select–driven command sequencing. It supports both SPI Mode 0 (CPOL=0, CPHA=0) and Mode 3 (CPOL=1, CPHA=1), with all instructions-including READ, WRITE, WREN, WRDI, RDSR, and WRSR-initiated by CS low transition.

Internal operation relies on an 8-bit instruction register and nonvolatile status register controlling write enable (WEN) and block protection (BP1/BP0). The device features self-timed internal write cycles (≤5 ms), automatic address increment during sequential reads/writes, and HOLD pin functionality to suspend ongoing communication without resetting the serial sequence.

Key Specifications

Pinout & Package

AT25040AN-10SI-2.7 is housed in an 8-lead JEDEC-standard SOIC package (package code 8S1), measuring 4.90 mm × 3.90 mm × 1.75 mm, with gull-wing leads and 1.27 mm pitch. This RoHS-compliant, lead-free/halogen-free package supports reflow soldering and fits standard 0.150" wide SOIC footprints.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25040AN-10SI-2.7, M95040-DRMN3TP/K offers superior ESD immunity in identical footprint, while BR24G04FJ-3GE2 trades SPI flexibility and HOLD/WP control for simpler two-wire integration at reduced throughput-neither is pin-compatible, requiring layout revision for substitution.

Availability

AT25040AN-10SI-2.7 is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, medical infusion pump configuration, and smart energy meter firmware patch storage requiring stable component supply across extended product lifecycles.

Supply support for AT25040AN-10SI-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 is a global semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with emphasis on reliability, longevity, and industrial-grade qualification.

The AT25040AN-10SI-2.7 belongs to Microchip's legacy Atmel SPI EEPROM product line, engineered for robust nonvolatile data storage in harsh environments where power loss resilience and long-term data integrity are mandatory.

FAQ

What is the maximum clock frequency supported by the AT25040AN-10SI-2.7 at 3.3V operation?

The AT25040AN-10SI-2.7 supports up to 10 MHz SCK frequency when operated at VCC = 2.7V–3.6V, as specified in Table 4 AC Characteristics. At 3.3V, this ensures reliable communication with common 3.3V microcontrollers such as STM32L4 or MSP430FR series without timing margin violations. The AT25040AN-10SI-2.7 datasheet confirms tWH/tWL minimums of 40 ns in this voltage range, corresponding to 10 MHz maximum.

Does the AT25040AN-10SI-2.7 require an external pull-up resistor on the SO pin?

No, the AT25040AN-10SI-2.7 does not require an external pull-up on the SO pin because it actively drives high or low during valid data transmission and enters high-impedance state when deselected (CS high) or during HOLD. External pull-ups may cause bus contention or increased standby current; the AT25040AN-10SI-2.7 design assumes clean tri-state behavior per SPI specification.

How is block write protection configured on the AT25040AN-10SI-2.7?

Block write protection on the AT25040AN-10SI-2.7 is set by writing BP1 and BP0 bits in the status register using the WRSR instruction. These nonvolatile bits define four protection levels: 00 = no protection, 01 = 25% protected (upper quarter), 10 = 50% protected (upper half), 11 = 100% protected. The AT25040AN-10SI-2.7 retains these settings across power cycles and respects them regardless of WP pin state.

Can the AT25040AN-10SI-2.7 be used with SPI Mode 3 (CPOL=1, CPHA=1)?

Yes, the AT25040AN-10SI-2.7 explicitly supports SPI Mode 3 per its datasheet Features section. In Mode 3, data is sampled on the falling edge of SCK and shifted out on the rising edge. The AT25040AN-10SI-2.7 maintains full timing compliance under Mode 3 conditions across its rated voltage and temperature range, enabling interoperability with Freescale Kinetis and NXP LPC families.

What happens if the WP pin is pulled low during an active write cycle on the AT25040AN-10SI-2.7?

If the WP pin is pulled low mid-write on the AT25040AN-10SI-2.7, the ongoing internal write operation completes normally-the WP signal has no effect once the write cycle has started. However, subsequent write attempts will be blocked until WP is returned high and WREN is re-executed. This behavior ensures data consistency while allowing hardware-based emergency lockout after critical writes.