Microchip Technology 24AA65/P

Overview

24AA65 from Microchip Technology Inc. is a 64 Kbit (8K × 8) I²C-compatible serial EEPROM with programmable high-endurance memory blocks, 1.8V–6.0V operation, 64-byte input cache, and Schmitt-triggered I²C interface. It delivers 10 million write cycles in a user-selectable 4K-bit block and 1 million cycles elsewhere, supporting low-power embedded systems requiring robust nonvolatile data logging.

For engineers reviewing the 24AA65 datasheet, 24AA65 pinout, 24AA65 application, or 24AA65 equivalent, key selection considerations include its dual endurance rating, page-write burst capability, programmable security blocks, I²C bus timing compatibility across voltage ranges, and PDIP/SOIJ package options for through-hole or surface-mount deployment.

Technical Context

The 24AA65 implements a two-wire I²C slave architecture with addressable device select lines (A0–A2), enabling up to eight devices on one bus. Its internal 64-byte FIFO cache supports burst writes without host intervention until Stop condition issuance.

It features dual endurance zones: a configurable 4K-bit high-endurance block (10M E/W cycles) and a standard 60K-bit array (1M E/W cycles), both protected by programmable write-security blocks spanning 0–15 contiguous 4K segments. The device uses self-timed erase/write cycles and includes V_CC monitoring for power-fail write protection.

Key Specifications

Pinout & Package

24AA65 is available in 8-pin PDIP (P) and 8-pin SOIJ (SM) packages. Both share identical pin mapping and electrical behavior.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA65, the 24LC65-I/P supports higher minimum supply voltage and wider temperature range but omits 1.8V operation; the AT24C64D offers broader voltage tolerance and smaller footprint but sacrifices programmable endurance and security - making 24AA65 uniquely suited for low-voltage, high-reliability, and secure embedded logging.

Availability

24AA65 is available at Aetrix Electronics and suitable for smart metering, industrial PLC configuration, medical sensor calibration, and automotive body control module designs requiring stable component supply, long-term data integrity, and field-programmable security.

Supply support for 24AA65 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 24AA65 belongs to Microchip's "Smart Serial EEPROM" product line, engineered specifically for applications demanding programmable endurance, hardware-enforced write security, and seamless integration into low-power I²C-based embedded systems.

FAQ

What is the maximum I²C clock frequency supported by the 24AA65?

The 24AA65 supports 100 kHz I²C operation across its full 1.8V–4.5V supply range and 400 kHz fast-mode operation when V_CC is between 4.5V and 6.0V. This dual-speed capability allows designers to optimize bus throughput based on system voltage without changing firmware or hardware interface logic. The 24AA65 maintains strict compliance with I²C timing specifications including setup/hold times and rise/fall time limits under both modes.

How does the 24AA65 handle write operations during power loss?

The 24AA65 incorporates dedicated V_CC monitor circuitry that disables write cycles whenever supply voltage drops below a safe threshold, preventing partial writes and data corruption. This protection operates independently of host software and remains active even during standby mode. Additionally, the device features power-on/off data protection circuitry that locks the memory array until stable V_CC is confirmed - ensuring 24AA65 retains valid data across uncontrolled power interruptions.

Can the high-endurance block of the 24AA65 be relocated after initial programming?

No - the location of the high-endurance block in the 24AA65 is programmable only once, and relocation becomes impossible after any security block has been configured with length greater than zero. If the high-endurance block is not explicitly programmed during initialization, it defaults to the highest 4K segment (0x1E00–0x1FFF). Once set, the 24AA65 preserves this configuration permanently, and attempts to reprogram it will be ignored by the internal control logic.

What is the function of the NC pin on the 24AA65 PDIP and SOIJ packages?

The NC (No Connection) pin on the 24AA65 is an unconnected die pad with no internal bond wire or circuit attachment. It must be left electrically floating in the PCB layout; tying it to V_CC, V_SS, or any signal net may cause unpredictable behavior or increased leakage. Microchip specifies this pin as strictly unused - unlike some other manufacturers' "NC" pins, the 24AA65 NC pin serves no thermal, shielding, or mechanical purpose and contributes no functional benefit when terminated.

Does the 24AA65 require external pull-up resistors on SDA and SCL lines?

Yes - the 24AA65 SDA and SCL pins are open-drain outputs and require external pull-up resistors to V_CC for proper I²C bus operation. Recommended values are 10 kΩ for 100 kHz standard-mode and 2 kΩ for 400 kHz fast-mode operation. These values ensure adequate rise time while limiting current draw; incorrect resistor selection can cause bus timing violations or excessive power consumption. The 24AA65 itself provides no internal pull-ups, making external termination mandatory for all 24AA65 implementations.