Microchip Technology 24AA32AX-I/ST

Overview

24AA32AX-I/ST from Microchip Technology Inc. is a 32 Kbit I²C-compatible serial EEPROM organized as 4K × 8-bit memory, operating from 1.8V to 5.5V with 1 μA standby current and 1 mA active current. It supports up to eight devices on one bus via A0–A2 address pins, features hardware write-protection (WP pin), and delivers 1 million erase/write cycles with >200-year data retention. It is used in low-power embedded systems for configuration storage and calibration data logging.

For engineers reviewing the 24AA32AX-I/ST datasheet, 24AA32AX-I/ST pinout, 24AA32AX-I/ST application, or 24AA32AX-I/ST equivalent, key selection criteria include its 1.8V minimum supply, 400 kHz I²C speed at ≥2.5V, TSSOP-8 package footprint, page-write buffer (32 bytes), and industrial temperature range (–40°C to +85°C).

Technical Context

The 24AA32AX-I/ST implements a standard two-wire I²C slave interface with Schmitt-trigger inputs on SDA and SCL for noise immunity, slope-controlled outputs to suppress ground bounce, and internal auto-erase during self-timed write cycles. Its address decoding uses three hardware-selectable bits (A0–A2) to support cascaded multi-device configurations.

It operates as a nonvolatile serial ROM with bidirectional data transfer, requiring external pull-up resistors on SDA/SCL. The WP pin provides hardware-level write protection for the full 4K-byte array, and acknowledge polling enables precise timing control of write completion without fixed delays.

Key Specifications

Pinout & Package

24AA32AX-I/ST is packaged in an 8-lead TSSOP (4.4 mm body width), RoHS-compliant, surface-mount package with 0.65 mm pitch. Pin 1 is marked by a dot or notch orientation indicator.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC32AT-I/ST, the 24AA32AX-I/ST enables 1.8V operation critical for energy-harvesting and coin-cell designs; versus AT24C32D-SSHM-T, it adds hardware write protection essential for safety-critical parameter storage.

Availability

24AA32AX-I/ST is available at Aetrix Electronics and suitable for smart metering, industrial PLC modules, medical sensor calibration, and automotive body control units requiring stable component supply across extended production lifecycles.

Supply support for 24AA32AX-I/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 components, and memory solutions, headquartered in Chandler, Arizona, with global manufacturing and support infrastructure.

The 24AA32A family was designed specifically for low-power, space-constrained embedded systems needing reliable, I²C-compatible nonvolatile storage with hardware write protection and wide supply voltage tolerance.

FAQ

What is the minimum operating voltage for the 24AA32AX-I/ST?

The 24AA32AX-I/ST operates down to 1.8V, making it compatible with modern ultra-low-power microcontrollers and battery-powered applications. This is a key differentiator from the 24LC32A variant, which requires a minimum of 2.5V. The 24AA32AX-I/ST maintains full I²C functionality-including 400 kHz operation-at VCC ≥ 2.5V, and falls back to 100 kHz below that threshold. All electrical specifications in the datasheet are validated across the 1.8V–5.5V range.

Does the 24AA32AX-I/ST support page writes, and what is the maximum buffer size?

Yes, the 24AA32AX-I/ST supports page writes with a 32-byte internal buffer. This allows up to 32 bytes to be loaded into the buffer before initiating a single self-timed write cycle, significantly reducing I²C bus overhead compared to byte-wise writes. Page boundaries align every 32 bytes (addresses 0x000–0x01F, 0x020–0x03F, etc.), and crossing a boundary causes wraparound within the current page-so firmware must ensure address alignment. The 24AA32AX-I/ST completes each page write in ≤5 ms.

How does the Write-Protect (WP) pin function on the 24AA32AX-I/ST?

The WP pin on the 24AA32AX-I/ST is an active-high hardware lock: when tied to VCC, it disables all write and erase operations to the entire 4K-byte memory array while permitting unrestricted reads. When tied to VSS (or left floating with pull-down), writes are enabled. The pin is sampled at the Stop bit of each write command, so toggling WP mid-operation has no effect. This provides deterministic, glitch-immune protection-critical for safeguarding calibration data or firmware configuration in deployed systems.

What package type is used for the 24AA32AX-I/ST, and what are its key mechanical dimensions?

The 24AA32AX-I/ST uses an 8-lead TSSOP package (JEDEC MO-153), designated "ST" in the part number. Its body measures 4.4 mm × 3.0 mm with 0.65 mm lead pitch. Total height is 1.10 mm max, standoff (A1) is 0.85–0.95 mm, and lead width (B) is 0.09–0.20 mm. The package is RoHS-compliant, Pb-free, and optimized for automated SMT assembly. Pin 1 is identified by a dot or notch; the exposed pad is not electrically connected.

Can multiple 24AA32AX-I/ST devices share the same I²C bus, and how is addressing managed?

Yes, up to eight 24AA32AX-I/ST devices can share a single I²C bus using hardware address lines A0, A1, and A2. These pins configure the three LSBs of the 7-bit slave address (base 0x50 = 1010000b), yielding addresses 0x50–0x57. Each device's A0–A2 must be hard-wired to VSS or VCC (not floated) to establish a unique address. The 24AA32AX-I/ST responds only when its configured address matches the transmitted control byte, enabling scalable memory expansion without software address translation.