Microchip Technology 24AA32AT-I/ST

Overview

24AA32AT-I/ST from Microchip Technology is a 32-Kbit I²C-compatible serial EEPROM organized as 4K × 8-bit, operating from 1.7V to 5.5V with 400 kHz max clock frequency, 1 µA standby current, and industrial temperature range (–40°C to +85°C). It features hardware write-protection via the WP pin, 32-byte page write buffer, and Schmitt-trigger inputs for noise immunity - deployed in embedded system configuration storage, sensor calibration data retention, and power-fail-safe parameter logging.

For engineers reviewing the 24AA32AT-I/ST datasheet, 24AA32AT-I/ST pinout, 24AA32AT-I/ST application, or 24AA32AT-I/ST equivalent, key selection criteria include low-voltage operation down to 1.7V, I²C bus compatibility at 100/400 kHz, hardware write-protect functionality, endurance of 1 million cycles, and data retention exceeding 200 years - all validated for industrial-grade reliability.

Technical Context

The 24AA32AT-I/ST implements a two-wire I²C interface with open-drain SDA/SCL pins requiring external pull-ups, supports up to eight devices on one bus via A0–A2 address inputs, and uses internal address pointer logic for sequential, random, and current-address read modes. Its page write architecture buffers up to 32 bytes before initiating a self-timed 5 ms erase/write cycle.

Write protection is controlled solely by the WP pin state (VSS = enabled, VCC = inhibited), sampled at the Stop bit; no software lock or register-based protection is present. The device incorporates Schmitt-trigger inputs and output slope control to suppress ground bounce and improve noise immunity on noisy PCBs.

Key Specifications

Pinout & Package

24AA32AT-I/ST is packaged in an 8-lead MSOP (Micro Small Outline Package) with 3 mm × 3 mm body, 0.65 mm pitch, and exposed pad optionally connected to VSS. Pin 1 is marked by a notch or dot; package conforms to JEDEC MO-187AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA32AT-I/ST, the 24LC32AT-I/ST trades lower-voltage capability for broader legacy support, while the AT24C32D-SSHM-T sacrifices address pin flexibility for improved ESD tolerance and simplified layout - making each alternative optimal only under specific voltage, topology, or reliability constraints.

Availability

24AA32AT-I/ST is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, smart energy metering, and automotive body control modules requiring stable component supply, long-term data retention, and AEC-Q100-compliant reliability.

Supply support for 24AA32AT-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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24AA32A family delivers cost-optimized, low-power serial EEPROMs targeting embedded systems requiring robust nonvolatile storage in space- and power-constrained applications - especially where 1.7V operation and industrial temperature range are mandatory.

FAQ

What is the minimum supply voltage required for reliable operation of the 24AA32AT-I/ST?

The 24AA32AT-I/ST operates reliably down to 1.7V across its full industrial temperature range (–40°C to +85°C). Below 2.5V, maximum I²C clock frequency is limited to 100 kHz; at 2.5V and above, it supports up to 400 kHz. This makes the 24AA32AT-I/ST uniquely suited for 1.8V logic systems without level shifters.

How does the WP pin function on the 24AA32AT-I/ST, and what happens if it floats?

The WP (Write-Protect) pin on the 24AA32AT-I/ST must be actively driven to either VSS (enables writes) or VCC (disables writes). If left floating, behavior is undefined and may result in partial or intermittent write inhibition. Microchip specifies that WP is sampled only at the Stop bit of each write command - toggling WP mid-cycle has no effect.

Can the 24AA32AT-I/ST perform page writes across multiple physical pages?

No. Page writes on the 24AA32AT-I/ST are strictly confined within a single 32-byte physical page boundary (e.g., addresses 0x000–0x01F, 0x020–0x03F). Attempting to write across a boundary causes wraparound within the current page, overwriting earlier bytes. Application firmware must enforce page-aligned write boundaries to avoid data corruption.

What is the purpose of the A0, A1, and A2 pins on the 24AA32AT-I/ST, and are they required?

The A0, A1, and A2 pins on the 24AA32AT-I/ST set the three LSBs of the I²C 7-bit client address (1010A2A1A0), enabling up to eight devices on the same bus. They are required for multi-device configurations but may be hardwired to VSS or VCC in single-device systems. In the SOT-23 variant, these pins are omitted - but the 24AA32AT-I/ST uses MSOP packaging and retains all three address inputs.

Does the 24AA32AT-I/ST support sequential reads across device boundaries when multiple units are connected?

No. While the 24AA32AT-I/ST supports contiguous addressing up to 256 Kbits using A0–A2 as address bits A12–A14 in software, sequential reads cannot cross device boundaries. Each 24AA32AT-I/ST responds only to its own 4K-word address space; reading beyond FFFh rolls over to 000h within that device, not to the next unit's memory map.