Microchip Technology 24AA04HT-I/OT

Overview

24AA04HT-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 (100 kHz below 2.5V), 1 µA standby current, and hardware write-protect for the upper half-array (100h–1FFh). It enables nonvolatile parameter storage in space-constrained industrial control modules.

For engineers reviewing the 24AA04HT-I/OT datasheet, 24AA04HT-I/OT pinout, 24AA04HT-I/OT application, or 24AA04HT-I/OT equivalent, key selection criteria include low-voltage operation down to 1.7V, Schmitt-trigger noise immunity on SDA/SCL, 16-byte page write buffer, half-array hardware write-protection, and I-temp (−40°C to +85°C) qualification in SOT-23 package.

Technical Context

The 24AA04HT-I/OT implements a two-wire I²C interface with fixed 4-bit device code '1010', block-select bit B0, and R/W bit - supporting byte and page writes up to 16 bytes within a single physical page boundary. Its internal address counter enables current-address, random, and sequential read modes without external addressing logic.

It uses CMOS EEPROM technology with self-timed erase/write cycles, slope-controlled outputs to suppress ground bounce, and integrated Schmitt-trigger inputs with ≥50 ns spike suppression. Write protection is implemented via the WP pin: tied to VCC disables writes to addresses 100h–1FFh while permitting full read access.

Key Specifications

Pinout & Package

24AA04HT-I/OT is housed in a 5-lead SOT-23 package (JEDEC MO-178AA), with 1.6 mm × 2.8 mm footprint and 1.1 mm height - optimized for high-density PCB layouts in portable and embedded systems.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA04HT-I/OT, the 24LC04BHT-I/OT sacrifices 1.7V compatibility for identical packaging and speed, while AT24C04D-SSHM-T offers voltage compatibility but omits hardware-based half-array write protection - making 24AA04HT-I/OT the optimal choice for 1.8V industrial designs requiring robust, hardware-enforced memory security.

Availability

24AA04HT-I/OT is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer appliance settings, and medical device serial ID storage requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for 24AA04HT-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 microcontrollers, analog components, and memory solutions, serving industrial, automotive, and consumer markets with vertically integrated silicon and development tools.

The 24AA04H family was designed specifically for low-voltage, space-constrained embedded systems needing reliable, low-power nonvolatile storage - emphasizing ease of integration, noise immunity, and hardware-level data protection.

FAQ

What is the maximum I²C clock frequency supported by the 24AA04HT-I/OT?

The 24AA04HT-I/OT supports up to 400 kHz when VCC is 2.5V or higher. At supply voltages between 1.7V and 2.5V, the maximum clock frequency is reduced to 100 kHz to ensure timing margin compliance. This dual-speed behavior is built into the device's internal timing generator and requires no external configuration. The 24AA04HT-I/OT automatically adapts to the applied VCC level without firmware intervention.

How does the hardware write-protection feature work on the 24AA04HT-I/OT?

The 24AA04HT-I/OT uses the WP pin to enable hardware write-protection: when WP is tied to VCC, writes to memory addresses 100h–1FFh are blocked while reads remain fully functional. Addresses 000h–0FFh stay writable. When WP is tied to VSS, full read/write access is enabled across the entire 4-Kbit array. This protection is active immediately on power-up and requires no command sequence or register setting.

Can the 24AA04HT-I/OT be used with a 1.8V microcontroller I²C interface?

Yes, the 24AA04HT-I/OT is fully compatible with 1.8V I²C interfaces. Its 1.7V–5.5V supply range allows direct connection to 1.8V rails, and its Schmitt-trigger inputs with hysteresis (≥5% VCC) ensure robust signal recognition even with marginal voltage margins. External pull-up resistors should be sized for 1.8V (e.g., 10 kΩ) to maintain rise-time specifications per I²C standard.

What is the page write buffer size of the 24AA04HT-I/OT, and how does it affect programming efficiency?

The 24AA04HT-I/OT features a 16-byte page write buffer. This allows up to 16 consecutive bytes to be loaded into the buffer and written to memory in a single internal cycle (max 5 ms), reducing I²C transaction overhead by eliminating repeated start/stop sequences. For example, writing 16 bytes requires only one Stop condition instead of 16 - cutting bus utilization by ~94% compared to byte-write mode.

Is the 24AA04HT-I/OT qualified for automotive applications?

No, the 24AA04HT-I/OT carries Industrial (I) temperature qualification (−40°C to +85°C) and is not AEC-Q100 certified. While the broader 24XX04H family includes AEC-Q100-qualified variants like the 24LC04BH, the 24AA04HT-I/OT variant is intended for industrial and commercial applications. For automotive body control or infotainment systems, Microchip's 24LC04BHT-E/OT (Extended temp, AEC-Q100 Grade 2) is the designated alternative.