Microchip Technology 24AA08/ST

Overview

24AA08/ST from Microchip Technology Inc. is an 8-Kbit I²C-compatible serial EEPROM organized as four 256 × 8-bit blocks, operating from 1.7V to 5.5V with 400 kHz max clock frequency (100 kHz below 2.5V), 16-byte page write buffer, and hardware write-protect via WP pin. It supports industrial temperature range (–40°C to +85°C) in 8-lead SOIC package and is used for nonvolatile parameter storage in embedded controllers and sensor calibration modules.

For engineers reviewing the 24AA08/ST datasheet, 24AA08/ST pinout, 24AA08/ST application, or 24AA08/ST equivalent, this page delivers verified electrical specs, validated SOIC-8 pin mapping, real-world use cases in power management and firmware configuration, and two confirmed alternative parts with documented functional and packaging differences.

Technical Context

The 24AA08/ST implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. Its internal address pointer enables current-address, random, and sequential read modes, while the 16-byte page buffer allows efficient burst writes without host-side timing constraints.

Write protection is implemented via the dedicated WP pin: tied to VSS for full read/write access, tied to VCC to disable all write operations across the entire 000–3FFh memory space. The device uses self-timed erase/write cycles with no external timing components required.

Key Specifications

Pinout & Package

8-Lead SOIC (SN) package with standard 1.27 mm pitch, 3.90 mm body width, and JEDEC MS-012AC compliant footprint. Pin 1 marked by notch or bevel; exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC08B/ST, the 24AA08/ST adds 1.7V operation for broader low-power compatibility; compared with 24FC08/ST, it trades 1 MHz speed for lower cost and wider legacy design acceptance - making it optimal for cost-sensitive, 1.8V–3.3V embedded systems requiring proven reliability.

Availability

24AA08/ST is available at Aetrix Electronics and suitable for industrial power supplies, medical diagnostics equipment, and automotive body control modules requiring stable component supply with guaranteed long-term availability.

Supply support for 24AA08/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 microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global manufacturing and support infrastructure.

The 24AA08/ST belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power nonvolatile data storage in space-constrained embedded systems across industrial, medical, and automotive markets.

FAQ

What is the maximum I²C clock frequency supported by the 24AA08/ST?

The 24AA08/ST supports up to 400 kHz when V_CC is 2.5V or higher; at 1.7V ≤ V_CC < 2.5V, the maximum clock frequency is reduced to 100 kHz to ensure signal integrity and timing margin. This dual-speed capability allows the 24AA08/ST to operate reliably across a wide range of supply voltages without external clock dividers or protocol adaptation. The 24AA08/ST datasheet specifies these limits in Table 1-1 AC Characteristics.

Does the 24AA08/ST require external pull-up resistors on SDA and SCL lines?

Yes, the 24AA08/ST requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. Typical values are 10 kΩ for 100 kHz operation, 2 kΩ for 400 kHz, and 1 kΩ for 1 MHz (though 24AA08/ST does not support 1 MHz). These resistors ensure proper logic-high levels and meet rise-time specifications defined in the 24AA08/ST AC characteristics table. Failure to install them will result in communication failure.

How does the write-protect (WP) pin function on the 24AA08/ST?

On the 24AA08/ST, the WP pin provides hardware-level write inhibition: when tied to VCC, all write operations (byte and page) to the entire 000–3FFh memory array are blocked, while read operations remain fully functional. When tied to VSS or left floating (not recommended), full read/write access is enabled. This feature is implemented entirely in silicon and requires no firmware interaction - making the 24AA08/ST resistant to accidental or malicious overwrites during system operation.

What is the endurance rating of the 24AA08/ST, and how is it measured?

The 24AA08/ST is rated for 1,000,000 erase/write cycles at 25°C and 5.5V, measured using page-mode writes per JEDEC Standard No. 22-A117. This endurance applies to the full memory array and is guaranteed across the industrial temperature range (–40°C to +85°C). Data retention exceeds 200 years under the same conditions, meaning the 24AA08/ST maintains stored values without refresh for decades - far exceeding typical product lifecycles in industrial and medical applications.

Can the 24AA08/ST be used in automotive applications?

The 24AA08/ST itself is not AEC-Q100 qualified; however, the broader 24XX08 family includes the 24LC08B and 24FC08 variants that are AEC-Q100 qualified for automotive use. For automotive body control or infotainment modules requiring qualification, engineers should select those variants instead. The 24AA08/ST remains suitable for industrial and medical applications operating within the same –40°C to +85°C temperature range but without formal automotive certification requirements.