Microchip Technology 24AA32AF-I/ST

Overview

24AA32AF-I/ST from Microchip Technology Inc. is a 32 Kbit I²C-compatible serial EEPROM organized as 4K × 8-bit memory, 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 24AA32AF-I/ST datasheet, 24AA32AF-I/ST pinout, 24AA32AF-I/ST application, or 24AA32AF-I/ST equivalent, key selection criteria include V_CC min (1.7V), I²C clock compatibility (100/400 kHz), standby current (1 μA max), page write time (5 ms max), and TSSOP-8 package footprint compatibility with space-constrained PCB layouts.

Technical Context

The 24AA32AF-I/ST implements a two-wire I²C slave interface with fixed 4-bit control code (1010b) and 3-bit chip address (A2–A0), enabling up to eight devices on one bus. Its internal address counter supports current-address, random, and sequential read modes, while page write logic buffers up to 32 bytes before initiating self-timed erase/write cycles.

Write protection is implemented via dedicated WP pin sampled at Stop condition, disabling writes only to addresses C00h–FFFh when pulled high. All I/O pins feature Schmitt-trigger inputs and slope-controlled outputs to suppress ground bounce and EMI, meeting I²C bus timing requirements across 1.7–5.5V supply range.

Key Specifications

Pinout & Package

24AA32AF-I/ST is supplied in 8-lead TSSOP package (3.0 mm × 4.4 mm, 0.65 mm pitch), RoHS-compliant and lead-free per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC32AF-I/ST, the 24AA32AF-I/ST enables lower-voltage operation critical for battery-backed systems, while AT24C32D-SSHM-T trades WP granularity for extended endurance-making 24AA32AF-I/ST optimal for safety-critical parameter storage where voltage headroom and hardware lock are mandatory.

Availability

24AA32AF-I/ST is available at Aetrix Electronics and suitable for industrial sensor nodes, medical calibration storage, automotive body control modules, and smart home gateways requiring stable component supply across extended production lifecycles.

Supply support for 24AA32AF-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 24AA32AF-I/ST belongs to Microchip's 24XX32AF family of I²C serial EEPROMs, engineered specifically for ultra-low-power, high-reliability nonvolatile data storage in space- and energy-constrained embedded systems.

FAQ

What is the minimum supply voltage required for reliable operation of the 24AA32AF-I/ST?

The 24AA32AF-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 to maintain timing margins. This low-voltage capability allows direct integration with 1.8V microcontrollers and energy-harvesting power supplies without level-shifting circuitry, making the 24AA32AF-I/ST ideal for battery-operated edge devices where every millivolt of headroom matters.

How does the hardware write-protect (WP) pin function on the 24AA32AF-I/ST?

The WP pin on the 24AA32AF-I/ST is sampled at the Stop condition of each write command. When pulled high to V_CC, it disables write operations exclusively to memory addresses C00h–FFFh (upper 8 Kbit), while permitting full read access and writes to the lower 24 Kbit. This quarter-array protection is implemented in hardware and cannot be overridden by software, providing tamper-resistant storage for boot code, security keys, or calibration constants. The 24AA32AF-I/ST continues normal operation-including reads and unprotected writes-when WP is asserted.

What is the maximum number of 24AA32AF-I/ST devices that can share the same I²C bus?

Up to eight 24AA32AF-I/ST devices can operate on a single I²C bus using unique combinations of the A0, A1, and A2 address pins. Each pin must be hardwired to either V_SS or V_CC, generating a 3-bit chip address that combines with the fixed 1010b control code to form a unique 7-bit slave address. This enables a total addressable memory space of 256 Kbit (8 × 32 Kbit) without external multiplexing, simplifying multi-parameter storage architectures in complex embedded systems using the 24AA32AF-I/ST.

Does the 24AA32AF-I/ST support sequential read operations across memory boundaries?

Yes, the 24AA32AF-I/ST supports continuous sequential reads across its entire 4K-word address space (000h–FFFh). After issuing a Start condition and control byte with R/W = 1, the device transmits data starting at the current address pointer and auto-increments the pointer after each byte. Upon reaching address FFFh, the pointer rolls over to 000h, allowing uninterrupted streaming of all 4,096 bytes in a single transaction. This behavior is confirmed in the DS22184A datasheet Section 8.3 and applies identically to the 24AA32AF-I/ST regardless of package variant.

What package type is used for the 24AA32AF-I/ST, and what are its key mechanical dimensions?

The 24AA32AF-I/ST is packaged in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 3.0 mm × 4.4 mm body size, 0.65 mm lead pitch, and 1.1 mm maximum height. Per Microchip's DS22184A-page 15, this package complies with JEDEC MO-153 standards and features matte tin (Pb-free) terminations. Its compact footprint and gull-wing leads support automated optical inspection and reflow soldering, making the 24AA32AF-I/ST suitable for high-density PCB layouts in consumer and industrial electronics.