Microchip Technology 24LC32AFT-I/ST

Overview

24LC32AFT-I/ST from Microchip Technology Inc. is a 32 Kbit I²C-compatible serial EEPROM organized as 4K × 8-bit memory, operating from 2.5V to 5.5V with industrial temperature range (–40°C to +85°C), 400 μA max read current, 1 μA max standby current, and hardware write-protect for upper 1/4 array (C00h–FFFh). It serves in embedded system configuration storage, sensor calibration data retention, and power-fail-safe parameter backup.

For engineers reviewing the 24LC32AFT-I/ST datasheet, 24LC32AFT-I/ST pinout, 24LC32AFT-I/ST application, or 24LC32AFT-I/ST equivalent, key selection criteria include VCC min (2.5V), I²C clock compatibility (100/400 kHz), page write buffer size (32 bytes), WP-enabled quarter-array protection, and TSSOP-8 package footprint compatibility with space-constrained PCB layouts.

Technical Context

The 24LC32AFT-I/ST implements a two-wire I²C interface with Schmitt-trigger inputs on SDA/SCL for noise immunity and slope-controlled outputs to suppress ground bounce. Its internal address counter supports current-address, random, and sequential reads, while the 32-byte page buffer enables efficient burst writes within physical page boundaries (0–31, 32–63, etc.).

Write protection is implemented via the WP pin: tied to VCC, it inhibits writes only to addresses C00h–FFFh (16 KiB), leaving lower 16 KiB fully writable; tied to VSS, full array write access is enabled. Acknowledge polling is supported to detect end-of-write-cycle completion without fixed timing delays.

Key Specifications

Pinout & Package

24LC32AFT-I/ST is housed in an 8-lead TSSOP package (3.0 mm × 4.4 mm, 0.65 mm pitch), RoHS-compliant and lead-free. Pin functions are electrically identical to PDIP/SOIC variants but optimized for surface-mount assembly density.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC32AFT-I/ST, the 24AA32AT-I/ST extends voltage range downward but shares identical timing and packaging, whereas the AT24C32D-SSHM-T removes hardware write protection entirely - making the 24LC32AFT-I/ST uniquely suited for applications demanding physical-layer security of configuration data.

Availability

24LC32AFT-I/ST is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, and smart energy metering requiring stable component supply across extended product lifecycles.

Supply support for 24LC32AFT-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, serving industrial, automotive, and consumer markets with high-reliability silicon and development tools.

The 24LC32AFT-I/ST belongs to Microchip's 24XX32AF family of I²C serial EEPROMs, designed specifically for low-power, noise-immune, and long-life nonvolatile data storage in resource-constrained embedded systems.

FAQ

What is the minimum supply voltage required for reliable operation of the 24LC32AFT-I/ST?

The 24LC32AFT-I/ST requires a minimum VCC of 2.5V for guaranteed operation across its full industrial temperature range (–40°C to +85°C). Unlike the 24AA32AF variant, it is not specified for operation below 2.5V. Attempting to use the 24LC32AFT-I/ST at 1.8V or 2.2V may result in unpredictable read/write behavior or failure to acknowledge I²C commands. Always maintain VCC ≥ 2.5V in designs using the 24LC32AFT-I/ST.

Does the 24LC32AFT-I/ST support 400 kHz I²C communication at all supply voltages?

Yes, the 24LC32AFT-I/ST supports up to 400 kHz I²C clock frequency when VCC is 2.5V or higher. The datasheet explicitly confirms 400 kHz operation across its entire rated VCC range (2.5V–5.5V). This differs from the 24AA32AF, which de-rates to 100 kHz below 2.5V - a distinction confirmed in the Device Selection Table on DS22184A-page 1. No voltage-dependent clock throttling applies to the 24LC32AFT-I/ST.

How does the hardware write-protect feature work on the 24LC32AFT-I/ST?

The WP pin on the 24LC32AFT-I/ST enables hardware write protection for the upper 1/4 memory array (addresses C00h–FFFh, or 16,384 bytes). When WP is tied to VCC, write attempts to that region are ignored - though the device still acknowledges the command. Reads remain fully functional. When WP is tied to VSS, full-array write access is restored. The pin state is sampled at the Stop condition of each write command, per Section 6.3 of DS22184A.

What package type is used for the 24LC32AFT-I/ST, and what are its key mechanical dimensions?

The 24LC32AFT-I/ST uses an 8-lead TSSOP package (Thin Shrink Small Outline Package) with body dimensions of 3.0 mm × 4.4 mm and 0.65 mm lead pitch. It complies with JEDEC MO-153 standards and features gull-wing leads for standard reflow soldering. The "T" in the part number explicitly denotes TSSOP, distinguishing it from SOIC (24LC32A-I/SN) or PDIP (24LC32A-I/P) variants.

Can multiple 24LC32AFT-I/ST devices share the same I²C bus, and how is addressing managed?

Yes, up to eight 24LC32AFT-I/ST devices can share one I²C bus using the A0, A1, and A2 address pins. These three pins form the LSBs of the 7-bit slave address (1010 A2 A1 A0 R/W), allowing unique addressing from 1010000 to 1010111. Each device must have a distinct combination of A0–A2 tied to VSS or VCC; floating pins are not permitted. The SOT-23 variant lacks these pins and supports only a fixed address.