Microchip Technology 24LC32AT-E/ST

Overview

24LC32AT-E/ST from Microchip Technology is a 32-Kbit I²C serial EEPROM organized as 4K × 8-bit memory, operating from 2.5V to 5.5V with 400 kHz clock support and industrial-extended temperature range (–40°C to +125°C). It features hardware write-protection via the WP pin, 32-byte page write buffer, and Schmitt-trigger inputs for noise immunity - deployed in automotive body control modules, industrial sensor nodes, and medical device calibration storage.

For engineers reviewing the 24LC32AT-E/ST datasheet, 24LC32AT-E/ST pinout, 24LC32AT-E/ST application, or 24LC32AT-E/ST equivalent, key selection criteria include VCC min/max compliance, I²C timing at extended temperature, WP pin behavior during power-up, and page boundary handling in firmware writes.

Technical Context

The 24LC32AT-E/ST implements a two-wire I²C interface with fixed 7-bit client address prefix '1010' and three programmable chip-select bits (A2–A0), enabling up to eight devices on one bus. Its internal address pointer auto-increments during sequential reads and supports current-address, random, and sequential read modes.

Write operations are self-timed with maximum 5 ms byte/page erase/write cycle; acknowledge polling is required to detect completion. The device uses an on-chip HV generator for EEPROM programming and includes slope-controlled outputs to suppress ground bounce during SDA transitions.

Key Specifications

Pinout & Package

24LC32AT-E/ST is supplied in an 8-lead SOIC package (ST suffix), 3.90 mm body width, with gull-wing leads and JEDEC MS-012AC outline. Pin 1 is marked by a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC32A-I/ST and AT24C32D-SSHM-T, the 24LC32AT-E/ST uniquely combines AEC-Q100 qualification, 125°C operation, and guaranteed 400 kHz I²C performance across its full voltage and temperature range - making it the only drop-in option for automotive and harsh-environment industrial use cases.

Availability

24LC32AT-E/ST is available at Aetrix Electronics and suitable for automotive body control units, industrial sensor calibration systems, and medical device configuration storage requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 24LC32AT-E/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, FPGA, and memory solutions, serving automotive, industrial, communications, and consumer markets with vertically integrated silicon and software.

The 24LC32A family delivers robust, low-power I²C EEPROMs designed specifically for automotive and extended-temperature industrial applications requiring high reliability, long data retention, and AEC-Q100 compliance.

FAQ

What is the maximum I²C clock frequency supported by the 24LC32AT-E/ST?

The 24LC32AT-E/ST supports up to 400 kHz I²C clock frequency when VCC is 2.5V or higher. At lower voltages (below 2.5V), the maximum clock rate drops to 100 kHz. This dual-speed capability ensures compatibility with both standard- and fast-mode I²C controllers while maintaining timing margin across its full operating voltage range. The 24LC32AT-E/ST datasheet specifies minimum high/low times and setup/hold requirements for both conditions.

How does the WP pin function on the 24LC32AT-E/ST?

The WP (Write-Protect) pin on the 24LC32AT-E/ST is an active-high input that inhibits all write and erase operations when pulled to VCC. When tied to VSS, normal read/write functionality is enabled. WP is sampled at the Stop bit of each write command, so toggling it mid-operation has no effect. This hardware-level protection prevents accidental overwrites during power-up, brown-out, or firmware errors - a critical feature in automotive and medical applications where data integrity is mandatory.

What is the page size and write buffer depth of the 24LC32AT-E/ST?

The 24LC32AT-E/ST has a 32-byte page write buffer and enforces strict 32-byte physical page boundaries (e.g., 0x000–0x01F, 0x020–0x03F). Writes crossing a page boundary wrap around within the current page instead of advancing to the next. This requires firmware to align multi-byte writes to page boundaries or split them across pages. The buffer allows up to 32 bytes to be loaded before initiating the internal 5 ms write cycle, improving I²C bus efficiency compared to byte-by-byte writes.

Is the 24LC32AT-E/ST qualified for automotive applications?

Yes, the 24LC32AT-E/ST is AEC-Q100 qualified for automotive use and rated for the extended temperature range of –40°C to +125°C. This qualification covers stress testing for thermal cycling, humidity, mechanical shock, and electrical reliability - confirming suitability for under-hood, chassis, and ADAS modules. The 'E' in the part number explicitly denotes Extended temperature grade, and the 'T' indicates tape-and-reel packaging compliant with automotive logistics standards.

What packages are available for the 24LC32AT-E/ST?

24LC32AT-E/ST is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with 3.90 mm body width and 'ST' suffix per Microchip's packaging nomenclature. This package meets JEDEC MS-012AC standards, features gull-wing leads, and is optimized for automated surface-mount assembly. Other variants like 24LC32A-I/ST use the same SOIC package but differ in temperature grade and qualification - the 'E' and 'T' in 24LC32AT-E/ST confirm extended temp and tape-and-reel delivery.