Microchip Technology 24AA02/ST

Overview

24AA02/ST from Microchip Technology Inc. is a 2-Kbit I²C-compatible serial EEPROM organized as 256 × 8-bit memory, operating from 1.7V to 5.5V with 400 kHz max clock frequency, 5 ms max page write time, and industrial temperature range (–40°C to +85°C). It features hardware write-protection via the WP pin and supports up to 1 million erase/write cycles for embedded system configuration storage.

For engineers reviewing the 24AA02/ST datasheet, 24AA02/ST pinout, 24AA02/ST application, or 24AA02/ST equivalent, this device serves as a low-voltage, noise-immune nonvolatile memory for microcontroller-based systems requiring reliable parameter retention, factory-programmable identity storage, and I²C bus integration in space-constrained designs.

Technical Context

The 24AA02/ST implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress ground bounce and bus noise. Its internal address pointer enables current-address, random, and sequential read modes, while the 8-byte page buffer supports efficient multi-byte writes without host-side timing constraints.

Write protection is implemented via a dedicated WP pin tied to VSS (enabled) or VCC (disabled), and the device uses an internal high-voltage generator for EEPROM programming. Acknowledge polling allows host firmware to detect write completion without fixed delays, optimizing I²C bus utilization during memory updates.

Key Specifications

Pinout & Package

24AA02/ST is supplied in an 8-lead SOIC package (SOIC-8, Microchip package code "ST"). Pin 1 is A0 (no internal connection), Pin 2 is A1 (NC), Pin 3 is A2 (NC), Pin 4 is VSS (ground), Pin 5 is SDA (bidirectional open-drain I²C data), Pin 6 is SCL (input-only I²C clock), Pin 7 is WP (write-protect input), and Pin 8 is VCC (power supply).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC02B/ST, the 24AA02/ST enables lower-voltage operation critical for energy harvesting and battery longevity; versus 24FC02/ST, it trades 1 MHz speed and +125°C rating for cost efficiency in industrial-grade applications where 400 kHz and +85°C suffice.

Availability

24AA02/ST is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and consumer IoT applications requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.

Supply support for 24AA02/ST 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 infrastructure.

The 24AA02/ST belongs to Microchip's 24XX02 family of I²C serial EEPROMs, designed specifically for reliable, low-power nonvolatile data storage in resource-constrained embedded systems where simplicity, robustness, and long-term data integrity are essential.

FAQ

What is the maximum I²C clock frequency supported by the 24AA02/ST?

The 24AA02/ST supports up to 400 kHz when VCC is 2.5V or higher. At supply voltages between 1.7V and 2.5V, the maximum clock frequency is reduced to 100 kHz to maintain timing margin and signal integrity. This dual-speed capability ensures interoperability across mixed-voltage I²C buses without external clock dividers or protocol translation.

Does the 24AA02/ST require external pull-up resistors on SDA and SCL lines?

Yes, the 24AA02/ST requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. A typical value is 2 kΩ for 400 kHz operation at 3.3V, though the exact resistance depends on bus capacitance and desired rise time. The 24AA02/ST itself does not integrate internal pull-ups, preserving design flexibility and minimizing quiescent current.

How does the WP pin function on the 24AA02/ST?

The WP (Write-Protect) pin on the 24AA02/ST is a logic-level input that disables all write operations when tied to VCC. When grounded (VSS), full read/write access is enabled. This hardware-level protection prevents accidental overwrites during power transitions or firmware errors, and remains active regardless of I²C command sequence - a critical safeguard for mission-critical configuration data stored in the 24AA02/ST.

Can the 24AA02/ST be used in automotive applications?

Yes, the 24AA02/ST is AEC-Q100 qualified for automotive applications and rated for the industrial temperature range (–40°C to +85°C), making it suitable for cabin electronics, body control modules, and infotainment systems. While not rated for under-hood +125°C operation (unlike the 24FC02 variant), its qualification ensures reliability against vibration, thermal cycling, and ESD stress encountered in vehicle platforms using the 24AA02/ST.

What is the purpose of the A0, A1, and A2 pins on the 24AA02/ST?

The A0, A1, and A2 pins on the 24AA02/ST are not internally connected and serve no functional role - they may be left floating or tied to VSS or VCC without affecting device operation. This design simplifies PCB routing and eliminates the need for external address-select resistors, distinguishing the 24AA02/ST from higher-density EEPROMs where these pins encode slave address bits.