Microchip Technology 25AA020A-I/P

Overview

25AA020A-I/P from Microchip Technology Inc. is a 2 Kbit (256 × 8) SPI Serial EEPROM with 1.8–5.5 V supply range, 10 MHz max clock frequency, and industrial temperature rating (−40°C to +85°C). It features write page mode (16-byte pages), hardware write protection via WP pin, and HOLD functionality for interrupt-safe serial communication. It is used in embedded systems for storing calibration data, configuration settings, and firmware parameters.

For engineers reviewing the 25AA020A-I/P datasheet, 25AA020A-I/P pinout, 25AA020A-I/P application, or 25AA020A-I/P equivalent, key selection criteria include its 1.8 V minimum operating voltage, 5 µA standby current, block write protection (BP0/BP1 bits), self-timed 5 ms write cycle, and compatibility with standard SPI Mode 0,0 and Mode 1,1 interfaces.

Technical Context

The 25AA020A-I/P implements a true SPI-compatible interface with separate SI (data in) and SO (data out) lines, requiring only CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. Its internal architecture includes an 8-bit instruction register, STATUS register with WIP/WEL/BP0/BP1 bits, and page latches enabling up to 16-byte page writes within fixed 16-byte boundaries.

Write operations require explicit WREN instruction followed by CS high-to-low transition to initiate internal 5 ms erase/write cycle; during this time, the WIP bit remains set and memory reads return undefined data. The device supports sequential read with automatic address rollover and uses hardware-level write protection via both WP pin and nonvolatile BP bits configured via WRSR.

Key Specifications

Pinout & Package

25AA020A-I/P is supplied in 8-lead PDIP (Plastic Dual In-line Package) with 0.300" body width, RoHS-compliant matte tin plating, and industrial-grade marking (e.g., "25AA020A", "I/P", date code).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA020A-I/P, the 25LC020A-I/P excludes 1.8 V operation but matches all other electrical and functional specs, while the AT25020B-SSHL-T omits BP0/BP1 block protection - making 25AA020A-I/P the only option supporting both ultra-low-voltage operation and hardware-enforced memory segmentation.

Availability

25AA020A-I/P is available at Aetrix Electronics and suitable for smart energy meters, industrial PLC I/O modules, medical diagnostic sensors, and automotive body control units requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 25AA020A-I/P 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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory products for embedded control applications.

The 25AA020A belongs to Microchip's 25XX020A family of SPI EEPROMs, designed specifically for reliable, low-power, and pin-compatible nonvolatile storage in resource-constrained microcontroller systems.

FAQ

What is the minimum supply voltage required for reliable operation of the 25AA020A-I/P?

The 25AA020A-I/P operates reliably down to 1.8 V over its full industrial temperature range (−40°C to +85°C). At VCC = 1.8 V, maximum clock frequency is 3 MHz, and AC timing parameters (e.g., TCSS, Tsu) scale accordingly per Table 1-2. This enables direct use with 1.8 V logic families without level translation.

How does the HOLD pin function during an active SPI transaction with the 25AA020A-I/P?

The HOLD pin suspends SPI communication mid-sequence: when pulled low while SCK is low, SI/SO/SCK inputs are ignored and SO enters high-impedance state. The 25AA020A-I/P retains internal state (address pointer, instruction phase) and resumes exactly where it left off upon HOLD returning high with SCK low - enabling safe interrupt handling in real-time systems.

Can the 25AA020A-I/P be used in systems requiring write protection of only the upper quarter of memory?

Yes. The 25AA020A-I/P supports four block protection levels via BP1/BP0 bits in its STATUS register. Setting BP1=0 and BP0=1 protects addresses C0h–FFh (upper 1/4, 64 bytes), leaving 00h–BFh freely writable - ideal for preserving factory calibration data while allowing user configuration updates.

What is the maximum write speed achievable with the 25AA020A-I/P in page mode?

In page mode, the 25AA020A-I/P accepts up to 16 bytes per write command, completing the entire internal write cycle in ≤5 ms regardless of byte count. This yields effective throughput of ~3.2 KB/s for full-page writes - significantly faster than issuing 16 individual byte-write commands, each requiring its own CS assertion and 5 ms delay.

Is the 25AA020A-I/P compatible with SPI Mode 3,0 (CPOL=1, CPHA=0)?

No. The 25AA020A-I/P supports only SPI Mode 0,0 (CPOL=0, CPHA=0) and Mode 1,1 (CPOL=1, CPHA=1), as confirmed by Figure 1-2 and Figure 1-3 timing diagrams. In Mode 0,0, data is sampled on the rising edge of SCK and changed on the falling edge - matching the device's SI/SO timing requirements.