Microchip Technology 24AA32AFT-I/OT

Overview

24AA32AFT-I/OT from Microchip Technology Inc. is a 32 Kbit I²C-compatible serial EEPROM organized as 4K × 8-bit, operating from 1.7V to 5.5V with industrial temperature range (–40°C to +85°C). It features 32-byte page write buffer, hardware write-protect for upper 1/4 array (C00h–FFFh), and Schmitt-trigger inputs for noise immunity. Used in low-power embedded systems for parameter storage, calibration data retention, and configuration backup.

For engineers reviewing the 24AA32AFT-I/OT datasheet, 24AA32AFT-I/OT pinout, 24AA32AFT-I/OT application, or 24AA32AFT-I/OT equivalent, key selection criteria include V_CC min (1.7 V), max clock frequency (400 kHz at V_CC ≥ 2.5 V), standby current (1 μA max), page write time (5 ms max), and TSSOP-5 package compatibility with SOT-23 footprint constraints.

Technical Context

The 24AA32AFT-I/OT implements a two-wire I²C interface with slave address format '1010' followed by three chip-select bits (A2–A0) and R/W bit - though A0–A2 are not present in the SOT-23 package variant. It uses internal charge-pump HV generator for EEPROM programming and supports both byte and page write modes with automatic address incrementing.

Write protection is controlled solely by the WP pin state sampled at Stop condition: tied to V_CC, it disables writes to addresses C00h–FFFh; tied to V_SS, full array access is enabled. Acknowledge polling is supported to detect end of self-timed write cycle (max 5 ms), and bus timing complies with standard-mode (100 kHz) and fast-mode (400 kHz) I²C specifications.

Key Specifications

Pinout & Package

24AA32AFT-I/OT is supplied in Pb-free, RoHS-compliant SOT-23-5 package (5-lead small-outline transistor). This compact surface-mount package measures 2.9 mm × 1.6 mm × 1.1 mm and is optimized for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA32AFT-I/OT, the 24LC32AFT-I/OT excludes 1.7 V operation but offers identical footprint and protection; the AT24C32D-MAHM-T adds speed headroom and voltage flexibility but removes hardware-based memory segmentation - impacting safety-critical write-locking assurance.

Availability

24AA32AFT-I/OT is available at Aetrix Electronics and suitable for smart metering, industrial sensor calibration, IoT identity management, and medical diagnostic equipment requiring stable component supply across extended production lifecycles.

Supply support for 24AA32AFT-I/OT 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, mixed-signal, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design, manufacturing, and sales operations.

The 24AA32AF family was designed specifically for ultra-low-power, space-constrained embedded systems requiring reliable nonvolatile storage with minimal external components and robust I²C interoperability.

FAQ

What is the minimum supply voltage for reliable operation of the 24AA32AFT-I/OT?

The 24AA32AFT-I/OT operates reliably down to 1.7 V across its full industrial temperature range (–40°C to +85°C). Below 2.5 V, maximum I²C clock frequency is limited to 100 kHz to maintain timing margins. This low-voltage capability enables direct integration with 1.8 V logic families without level-shifting circuitry, making the 24AA32AFT-I/OT ideal for energy-harvesting and battery-backed applications where supply voltage may sag during discharge.

Does the 24AA32AFT-I/OT support multiple devices on the same I²C bus?

No - the 24AA32AFT-I/OT uses the SOT-23-5 package, which omits the A0, A1, and A2 address pins required for multi-device addressing. Its fixed I²C slave address is 1010xxx0 (write) / 1010xxx1 (read), where the xxx bits are hardwired to '000'. Therefore, only one 24AA32AFT-I/OT can reside on a given I²C bus segment. For multi-device configurations, use the 8-pin variants (e.g., 24AA32AF-I/P) that expose all three address inputs.

How does hardware write-protection work on the 24AA32AFT-I/OT?

Hardware write-protection on the 24AA32AFT-I/OT is controlled exclusively by the WP pin: when tied to V_CC, writes to memory addresses C00h–FFFh (upper 8,192 bits) are blocked while reads remain fully functional; when tied to V_SS, full read/write access is enabled. The WP state is sampled only at the Stop condition of each write command - toggling WP mid-operation has no effect. This provides deterministic, glitch-immune protection for critical firmware or security data without software intervention.

What is the maximum page write size and timing for the 24AA32AFT-I/OT?

The 24AA32AFT-I/OT supports a 32-byte page write buffer, allowing up to 32 bytes to be loaded into the on-chip latch before initiating the internal write cycle. The maximum self-timed write cycle duration is 5 ms, regardless of whether one byte or 32 bytes are written. Page boundaries align to 32-byte intervals (e.g., 000h–01Fh, 020h–03Fh); crossing a boundary causes wraparound within the current page - software must enforce alignment to avoid unintended overwrites.

Is the 24AA32AFT-I/OT compatible with fast-mode I²C (400 kHz)?

Yes - the 24AA32AFT-I/OT fully supports I²C fast-mode operation at 400 kHz when V_CC is 2.5 V or higher. At V_CC between 1.7 V and 2.5 V, maximum clock frequency reverts to 100 kHz to ensure setup/hold time compliance. All AC timing parameters (e.g., THD:STA, TSU:DAT, TAA) are specified across both ranges, and the device meets standard I²C electrical requirements including open-drain SDA/SCL, Schmitt-trigger inputs, and slew-rate controlled outputs.