Microchip Technology 24AA64F-I/ST

Overview

24AA64F-I/ST from Microchip Technology Inc. is a 64 Kbit I²C-compatible serial EEPROM organized as 8K × 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 (1800h–1FFFh), and Schmitt-trigger inputs for noise immunity. Used in embedded systems for parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 24AA64F-I/ST datasheet, 24AA64F-I/ST pinout, 24AA64F-I/ST application, or 24AA64F-I/ST equivalent, key selection criteria include low-voltage operation down to 1.7V, 400 kHz I²C clock support, 1 μA standby current, and TSSOP-8 package compatibility with space-constrained PCB layouts.

Technical Context

The 24AA64F-I/ST implements a standard two-wire I²C interface with slave addressing via A0–A2 pins (hardwired or externally driven), supporting up to eight devices on one bus. Its internal address pointer enables sequential, random, and current-address read modes, while acknowledge polling allows precise timing of write-cycle completion without fixed delays.

Write operations are self-timed: byte writes complete in ≤5 ms typical, and page writes (up to 32 bytes within same physical page) use an on-chip buffer. The WP pin provides hardware-level protection for addresses 1800h–1FFFh when pulled high, independent of software control or I²C command state.

Key Specifications

Pinout & Package

24AA64F-I/ST is supplied in an 8-lead TSSOP package (3.0 mm × 4.4 mm, 0.65 mm pitch), RoHS-compliant and Pb-free. Pin assignments match industry-standard I²C EEPROM layout for drop-in compatibility with existing designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC64F-I/ST, the 24AA64F-I/ST enables lower-voltage operation critical for modern ultra-low-power MCUs, while the AT24C64D-SSHM-T offers enhanced system-level control at the cost of reduced hardware-level write protection assurance.

Availability

24AA64F-I/ST is available at Aetrix Electronics and suitable for smart metering, industrial PLC modules, medical diagnostics, and automotive body control units requiring stable component supply across multi-year production cycles.

Supply support for 24AA64F-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 manufacturing and support infrastructure.

The 24AA64F belongs to Microchip's serial EEPROM product line, designed specifically for reliable, low-power, I²C-based nonvolatile data storage in industrial, medical, and consumer applications demanding long-term data integrity.

FAQ

What is the minimum operating voltage for the 24AA64F-I/ST?

The 24AA64F-I/ST operates down to 1.7V, enabling direct integration with 1.8V microcontrollers and eliminating the need for level-shifting circuitry. This specification is validated across the full industrial temperature range (–40°C to +85°C) and applies to both read and write operations, making the 24AA64F-I/ST suitable for battery-powered or energy-harvesting systems where supply voltage may dip below 2.5V.

How does the hardware write-protect feature work on the 24AA64F-I/ST?

The WP pin on the 24AA64F-I/ST provides hardware-level protection for the upper 1/4 memory array (addresses 1800h–1FFFh). When WP is tied to VCC, write operations to that region are inhibited while reads remain fully functional. The protection is sampled at the Stop bit of each write command, ensuring robustness against transient noise. This mechanism is independent of I²C commands and cannot be overridden in software, making it ideal for safeguarding bootloader code or cryptographic keys stored in the protected zone.

Can the 24AA64F-I/ST be used on the same I²C bus with other 24XX64F-family devices?

Yes, the 24AA64F-I/ST supports multi-device I²C bus operation using its A0, A1, and A2 address pins. These three pins allow up to eight uniquely addressed 24AA64F-I/ST devices (or mixed 24AA64F/24LC64F/24FC64F) on a single bus, enabling scalable memory expansion up to 512 Kbit. Each device responds only to its configured 3-bit chip address, and the 24AA64F-I/ST's 1010xxx binary slave address prefix ensures compatibility with standard I²C address decoding logic.

What is the maximum I²C clock frequency supported by the 24AA64F-I/ST?

The 24AA64F-I/ST supports up to 400 kHz I²C clock frequency when VCC is 2.5V or higher. At VCC levels between 1.7V and 2.5V, the maximum clock rate is limited to 100 kHz to ensure timing margin compliance. This dual-speed capability allows the 24AA64F-I/ST to operate reliably across diverse supply conditions while maintaining full compatibility with standard-mode I²C controllers found in most microcontrollers and SoCs.

Does the 24AA64F-I/ST require external pull-up resistors on SDA and SCL lines?

Yes, the 24AA64F-I/ST uses open-drain SDA and SCL terminals and requires external pull-up resistors to VCC. Recommended values are 2 kΩ for 400 kHz operation and 10 kΩ for 100 kHz. Pull-up placement should be close to the 24AA64F-I/ST pins to minimize trace capacitance, and values must be adjusted based on bus capacitance and number of devices to meet I²C rise-time specifications (TR ≤1000 ns at 1.7V, ≤300 ns at ≥2.5V).