Microchip Technology 25AA020AT-I/SN

Overview

25AA020AT-I/SN from Microchip Technology Inc. is a 2 Kbit SPI Serial EEPROM with 256 × 8-bit organization, 1.8–5.5 V supply range, and industrial temperature rating (−40°C to +85°C). It supports up to 10 MHz clock frequency, 16-byte page write mode, and hardware write protection via WP pin - used for nonvolatile parameter storage in microcontroller-based sensor nodes and power management systems.

For engineers reviewing the 25AA020AT-I/SN datasheet, 25AA020AT-I/SN pinout, 25AA020AT-I/SN application, or 25AA020AT-I/SN equivalent, key selection criteria include SPI timing compliance at 1.8 V, block write-protection granularity (none/¼/½/all), endurance of 1 million erase/write cycles, and SOIC-8 (SN) package compatibility with legacy PCB layouts.

Technical Context

The 25AA020AT-I/SN implements a standard SPI Mode 0,0/Master-Slave interface with separate SI (data-in) and SO (data-out) lines, CS-controlled selection, and HOLD pin for transaction suspension. Its internal architecture includes an 8-bit instruction register, page latches, and high-voltage generator for EEPROM programming.

Write operations require explicit WREN instruction followed by CS high transition to initiate self-timed internal write cycle (≤5 ms); STATUS register (WIP/WEL/BP0/BP1 bits) enables real-time monitoring and configurable block protection. Power-on reset clears WEL and places SO in high-impedance state.

Key Specifications

Pinout & Package

25AA020AT-I/SN is packaged in 8-lead SOIC (SN), with 1.27 mm pitch, 4.9 mm × 3.9 mm body size, and Pb-free/RoHS-compliant finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA020AT-I/SN, the 25LC020AT-I/SN offers identical functionality above 2.5 V but excludes 1.8 V operation, while the AT25020B-MAHL-T provides faster timing and lower voltage support but removes hardware write protection - making 25AA020AT-I/SN optimal for cost-sensitive, robust industrial designs requiring both 1.8 V compatibility and physical WP enforcement.

Availability

25AA020AT-I/SN is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, and automotive body electronics requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for 25AA020AT-I/SN 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 Inc. is a leading provider of microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA020A family was designed specifically for reliable, low-power nonvolatile data storage in resource-constrained embedded systems - emphasizing SPI simplicity, wide voltage operation, and robust write protection for industrial and automotive applications.

FAQ

What is the maximum clock frequency supported by the 25AA020AT-I/SN across its full voltage range?

The 25AA020AT-I/SN supports up to 10 MHz at VCC ≥ 4.5 V, 5 MHz at 2.5 V ≤ VCC < 4.5 V, and 3 MHz at 1.8 V ≤ VCC < 2.5 V. These AC timing limits are fully characterized and guaranteed across the industrial temperature range (−40°C to +85°C), ensuring deterministic SPI performance in mixed-voltage systems where the 25AA020AT-I/SN interfaces with both 1.8 V and 5 V MCUs.

How does the 25AA020AT-I/SN handle page boundary crossing during a page write operation?

The 25AA020AT-I/SN enforces strict page alignment: a page write operation that crosses a 16-byte boundary wraps around to the start of the same page, overwriting previously loaded data. For example, writing 16 bytes starting at address 0x0F fills addresses 0x0F–0x1E, then wraps to 0x10–0x1F. This behavior is documented in DS21833G-page 6 and requires application firmware to validate address ranges before initiating page writes - a constraint not present in byte-write-only EEPROMs.

Can the 25AA020AT-I/SN be used in a 3.3 V system with a 5 V tolerant microcontroller SPI interface?

Yes - the 25AA020AT-I/SN operates natively at 3.3 V and features VIH1 = 0.7×VCC (min), meaning its SI and CS inputs recognize ≥2.31 V as logic high when VCC = 3.3 V. Since most 5 V-tolerant MCUs drive outputs to ≥3.3 V at 3.3 V IO supply, direct connection is safe. However, SO output high voltage (VOH = VCC − 0.5 V) reaches only 2.8 V at 3.3 V, so ensure host MCU input thresholds accommodate this level.

What happens to the write enable latch (WEL) during a power cycle or when the WP pin is asserted?

The 25AA020AT-I/SN resets the WEL on power-up, after successful WRDI or WRSR execution, after any completed WRITE operation, and immediately when WP is driven low - as specified in DS21833G-page 9. This multi-layer reset ensures write operations cannot proceed unless explicitly enabled post-power-on and while WP remains high, providing fail-safe protection against unintended writes during brown-out or configuration errors.

Is the 25AA020AT-I/SN pin-compatible with other Microchip 2 Kbit SPI EEPROMs like the 25LC020A?

Yes - the 25AA020AT-I/SN shares identical pinout, package dimensions, and functional pin definitions with the 25LC020AT-I/SN and all other 25XX020A variants in SOIC-8 (SN) packaging. Both devices use the same CS/SO/WP/VSS/SI/SCK/HOLD/VCC arrangement and support identical instruction set, timing, and protection features - enabling direct substitution where 1.8 V operation is not required for the 25LC020A variant.