Microchip Technology 24AA08H-I/ST

Overview

24AA08H-I/ST from Microchip Technology Inc. is an 8 Kbit I²C-compatible serial EEPROM organized as four 256 × 8-bit blocks, operating from 1.7V to 5.5V with industrial temperature range (–40°C to +85°C) and 400 kHz max clock frequency. It features hardware write-protection for half the array (200h–3FFh), 16-byte page write buffer, and Schmitt-trigger inputs for noise immunity - deployed in embedded system configuration storage, sensor calibration data retention, and power-fail-safe parameter backup.

For engineers reviewing the 24AA08H-I/ST datasheet, 24AA08H-I/ST pinout, 24AA08H-I/ST application, or 24AA08H-I/ST equivalent, key selection criteria include low-voltage operation down to 1.7V, half-array hardware write-protect via WP pin, 1 μA standby current, and compatibility with standard I²C bus timing at both 100 kHz and 400 kHz.

Technical Context

The 24AA08H-I/ST implements a slave-only I²C interface with fixed 4-bit device code '1010' and 3-bit block-select addressing, enabling access to four independent 256-word memory blocks. Its internal address pointer auto-increments during sequential reads and page writes, supporting current-address, random, and sequential read modes.

Write protection is implemented via dedicated WP pin: tied to VCC, it disables writes to addresses 200h–3FFh while permitting full read access; tied to VSS, full read/write functionality is enabled. The device uses on-chip charge-pump circuitry for EEPROM programming and includes VCC threshold detection to inhibit writes below 1.5V.

Key Specifications

Pinout & Package

24AA08H-I/ST is supplied in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 4.4 mm body width, RoHS-compliant matte tin finish, and standard JEDEC MO-153 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA08H-I/ST, the 24LC08BH-I/ST offers identical functionality above 2.5V but lacks sub-2.5V operation, while the AT24C08C-SSHM-T trades endurance and retention for broader vendor availability - making 24AA08H-I/ST optimal for 1.7V–2.5V battery systems demanding 200-year data integrity.

Availability

24AA08H-I/ST is available at Aetrix Electronics and suitable for industrial sensor nodes, smart energy meters, and medical diagnostic devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 24AA08H-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 microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24AA08H belongs to Microchip's serial EEPROM product line, engineered for robust, low-voltage nonvolatile data storage in space-constrained embedded systems where reliability, low power, and I²C simplicity are critical.

FAQ

What is the minimum VCC voltage required for reliable operation of the 24AA08H-I/ST?

The 24AA08H-I/ST operates reliably down to 1.7V VCC across its full industrial temperature range (–40°C to +85°C). Below this threshold, the internal VCC detector disables write operations to prevent data corruption, though read access may remain functional until ~1.5V. This makes the 24AA08H-I/ST suitable for direct interfacing with 1.8V microcontrollers and battery-powered systems experiencing gradual voltage sag.

How does the WP pin function on the 24AA08H-I/ST, and what memory region does it protect?

The WP (Write-Protect) pin on the 24AA08H-I/ST enables hardware-level write inhibition for the upper half of the memory array (addresses 200h–3FFh) when tied to VCC. When WP = VSS, full read/write access to all 1024 bytes is permitted. This selective protection allows critical calibration data or security keys stored in the upper block to remain immutable while permitting dynamic updates to configuration parameters in the lower block (000h–1FFh).

Can the 24AA08H-I/ST perform page writes across memory block boundaries?

No. Page writes on the 24AA08H-I/ST are constrained to a single 16-byte physical page - defined by addresses aligned to multiples of 16 (e.g., 000h–00Fh, 010h–01Fh). Attempting to write across a page boundary causes the address counter to wrap within the current page, overwriting earlier bytes. Applications must implement software checks to split multi-page writes, ensuring each 24AA08H-I/ST page write command stays within its 16-byte boundary.

What is the maximum I²C clock frequency supported by the 24AA08H-I/ST, and under what conditions?

The 24AA08H-I/ST supports up to 400 kHz I²C clock frequency when VCC is ≥2.5V. At VCC < 2.5V (e.g., 1.7V–2.4V), the maximum clock frequency is reduced to 100 kHz to maintain timing margin compliance. This dual-speed capability ensures interoperability with both standard-mode and fast-mode I²C masters while preserving signal integrity at low supply voltages.

Does the 24AA08H-I/ST require external pull-up resistors on SDA and SCL, and what values are recommended?

Yes - the 24AA08H-I/ST has open-drain SDA and SCL pins requiring external pull-up resistors to VCC. For 100 kHz operation, 10 kΩ is typical; for 400 kHz, 2 kΩ is recommended to meet rise-time specifications (≤1000 ns at 5V, ≤300 ns at 1.7V). Pull-up values must be adjusted based on bus capacitance and VCC level to ensure THD:STA, TSU:DAT, and other AC timing parameters remain within datasheet limits.