Microchip Technology 24AA04H-I/MS

Overview

24AA04H-I/MS 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 hardware write-protect for the upper half-array (100h–1FFh). It is used in embedded systems for storing calibration data, configuration settings, and firmware parameters.

For engineers reviewing the 24AA04H-I/MS datasheet, 24AA04H-I/MS pinout, 24AA04H-I/MS application, or 24AA04H-I/MS equivalent, key selection considerations include its industrial temperature range (−40°C to +85°C), MSOP-8 package footprint, 16-byte page write buffer, Schmitt-trigger I²C inputs for noise immunity, and half-array hardware write-protection via the WP pin.

Technical Context

The 24AA04H-I/MS implements a two-wire I²C interface with fixed 4-bit device code '1010', block-select addressing (B0 bit), and R/W control. Its internal address counter supports current-address, random, and sequential read modes, while the 16-byte page buffer enables efficient multi-byte writes without host-side timing constraints.

Write protection is implemented via the WP pin: tied to VSS enables full-array access; tied to VCC locks addresses 100h–1FFh against writes while permitting reads. The device uses on-chip charge-pump circuitry for EEPROM programming and includes built-in slope control on SDA/SCL to suppress ground bounce during transitions.

Key Specifications

Pinout & Package

24AA04H-I/MS is housed in an 8-lead MSOP (Mini Small Outline Package) with 3.0 mm × 3.0 mm body, 0.65 mm pitch, and exposed pad option (not connected internally). Pin 1 is marked with a dot or beveled edge.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA04H-I/MS, the 24LC04BH-I/MS lacks low-voltage capability but offers drop-in compatibility in 2.5V+ designs, while the 24FC04H-I/MS delivers 2.5× faster I²C throughput at identical voltage and packaging - making it ideal for time-critical parameter updates.

Availability

24AA04H-I/MS is available at Aetrix Electronics and suitable for smart meter calibration storage, industrial sensor configuration, and medical device settings backup requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for 24AA04H-I/MS 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, headquartered in Chandler, Arizona, with global manufacturing and support infrastructure.

The 24AA04H belongs to Microchip's 24XX04H family of I²C serial EEPROMs, designed specifically for space-constrained, low-power embedded systems requiring reliable nonvolatile storage with minimal external components and robust noise immunity.

FAQ

What is the maximum I²C clock frequency supported by the 24AA04H-I/MS?

The 24AA04H-I/MS supports up to 400 kHz when VCC is 2.5V or higher. At supply voltages between 1.7V and 2.49V, the maximum clock frequency is reduced to 100 kHz to maintain timing margin and signal integrity. This dual-speed behavior is inherent to the device's internal timing generator and does not require software configuration. The 24AA04H-I/MS datasheet specifies these limits in Table 1-2 under AC Characteristics.

How does the WP pin function on the 24AA04H-I/MS?

On the 24AA04H-I/MS, the WP (Write-Protect) pin controls hardware-level memory locking: when tied to VCC, writes to addresses 100h–1FFh are inhibited while reads remain fully enabled; when tied to VSS, full-array read/write access is permitted. The 24AA04H-I/MS does not support software write-protection - this function is exclusively hardware-gated by the WP pin state, providing deterministic, glitch-immune protection.

Can the 24AA04H-I/MS operate from a 1.8V supply?

Yes, the 24AA04H-I/MS is fully specified for operation from 1.7V to 5.5V, making it compatible with standard 1.8V logic systems without level translation. At 1.8V, it operates at 100 kHz I²C speed and maintains 1 µA standby current and full 4-Kbit memory functionality. This capability is explicitly confirmed in the Device Selection Table and Electrical Characteristics sections of the 24AA04H-I/MS datasheet.

What is the purpose of the A0, A1, and A2 pins on the 24AA04H-I/MS?

The A0, A1, and A2 pins on the 24AA04H-I/MS are not connected internally and serve no functional role. They may be left unconnected, tied to VSS, or tied to VCC without affecting device operation. This differs from larger-density EEPROMs (e.g., 24AA64) where these pins encode slave address bits - the 24AA04H-I/MS uses a fixed 4-bit device code (1010) and block-select bit (B0), rendering A0–A2 redundant.

Does the 24AA04H-I/MS support page write operations, and what is the buffer size?

Yes, the 24AA04H-I/MS supports page write operations with a 16-byte on-chip buffer. After receiving the control byte and word address, the host may transmit up to 16 consecutive data bytes before issuing a STOP condition; the device then writes all buffered bytes in a single self-timed cycle. Attempting to write beyond 16 bytes within one page causes wraparound, overwriting earlier bytes in the same physical page - software must enforce page boundaries (00h–0Fh, 10h–1Fh, etc.).