Microchip Technology 24AA04T-I/OT

Overview

24AA04T-I/OT from Microchip Technology Inc. is a 4-Kbit I²C-compatible serial EEPROM organized as two 256 × 8-bit blocks, 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 supports 16-byte page writes, hardware write-protection via WP pin, and is packaged in SOT-23-5 for space-constrained embedded systems.

For engineers reviewing the 24AA04T-I/OT datasheet, 24AA04T-I/OT pinout, 24AA04T-I/OT application, or 24AA04T-I/OT equivalent, this page delivers verified electrical specs, I²C timing constraints at 1.7V–5.5V, package-specific terminal mapping, endurance (1M cycles), data retention (>200 years), and real-world use cases in sensor calibration storage and firmware parameter backup.

Technical Context

The 24AA04T-I/OT implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. Its internal address pointer enables current-address, random, and sequential read modes, while ACK polling allows host-driven write-cycle completion detection without fixed delays.

It uses a self-timed erase/write cycle with 5 ms maximum page write time and integrates a 16-byte page latch buffer. The device ignores A0–A2 pins (no internal connection), simplifying address configuration - only block-select bit B0 in the control byte determines access to one of two 256-word memory blocks.

Key Specifications

Pinout & Package

SOT-23-5 package: 5-pin surface-mount package with 1.6 mm × 2.9 mm footprint, wettable flanks option available, optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC04B-I/OT, the 24AA04T-I/OT enables lower-voltage operation; compared with 24FC04T-I/OT, it trades 1 MHz speed for broader legacy compatibility and identical cost structure in SOT-23-5 packaging.

Availability

24AA04T-I/OT is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer electronics firmware storage, medical device configuration backup, and automotive body control module parameter retention requiring stable component supply across extended production lifecycles.

Supply support for 24AA04T-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.

The 24AA04T-I/OT belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power, I²C-based nonvolatile data storage in space- and cost-constrained embedded systems.

FAQ

What is the minimum supply voltage required for reliable operation of the 24AA04T-I/OT?

The 24AA04T-I/OT operates reliably down to 1.7V across its full industrial temperature range (–40°C to +85°C). At VCC < 2.5V, the maximum I²C clock frequency is reduced to 100 kHz to maintain timing margins. This low-voltage capability allows direct interfacing with 1.8V logic families without level shifters, making the 24AA04T-I/OT ideal for battery-powered and energy-harvesting applications where power efficiency is critical.

How does the WP pin function on the 24AA04T-I/OT, and what happens when it is left unconnected?

The WP (Write-Protect) pin on the 24AA04T-I/OT is a dedicated hardware enable/disable control: tying it to VCC locks the entire 4-Kbit memory array against write operations while permitting unlimited reads; tying it to VSS enables full read/write access. The datasheet explicitly states that leaving WP floating is not recommended - it must be actively driven to VSS or VCC. Uncontrolled states may result in intermittent or unintended write protection, compromising system reliability. The 24AA04T-I/OT does not include internal pull-up/down resistors on WP.

Can the 24AA04T-I/OT perform page writes across memory block boundaries?

No, the 24AA04T-I/OT cannot perform page writes across memory block boundaries. Its 4-Kbit array is split into two independent 256-word blocks (000–0FFh and 100–1FFh), selected by the B0 bit in the I²C control byte. Page writes are confined within a single block and will wrap around at the 16-byte physical page boundary (e.g., writing 16 bytes starting at address 0xF0 wraps to 0xF0–0xFF then 0x00–0x0F). Crossing from block 0 to block 1 during a page write is not supported and results in undefined behavior - software must enforce block-aligned addressing.

What is the purpose of ACK polling with the 24AA04T-I/OT, and how is it implemented?

ACK polling is used to detect completion of an internal write cycle in the 24AA04T-I/OT without fixed delays. After issuing a Stop condition to initiate a write, the host sends a repeated Start followed by the write control byte (R/W = 0). If the 24AA04T-I/OT is still busy, it withholds acknowledgment; when ready, it returns ACK, signaling the host to proceed. This method maximizes I²C bus utilization and eliminates worst-case 5 ms timeout waits. The 24AA04T-I/OT does not generate ACK during active write cycles - a guaranteed timing-independent status signal.

Is the 24AA04T-I/OT AEC-Q100 qualified, and what does that mean for automotive use?

Yes, the 24AA04T-I/OT is AEC-Q100 qualified for Grade 3 (–40°C to +85°C), confirming its suitability for automotive body electronics applications such as door modules and lighting controls. This qualification includes stress testing for temperature cycling, humidity bias, ESD, and accelerated life simulation - validating reliability under harsh vehicle environments. While not rated for under-hood engine bay temperatures (Grade 1), its qualification covers cabin and exterior non-powertrain systems where the 24AA04T-I/OT delivers proven data integrity and long-term stability.