Microchip Technology 24LC025/ST

Overview

24LC025/ST from Microchip Technology Inc. is a 2 Kbit (256 × 8) I²C-compatible serial EEPROM designed for nonvolatile data storage in space-constrained embedded systems. It operates from 2.5V to 5.5V, supports 400 kHz clock rate (100 kHz below 2.5V), features 16-byte page write buffer, and delivers ≤5 ms write cycle time with >1 million erase/write cycles and >200 years data retention. It is commonly used for configuration storage in industrial controllers and automotive body modules.

For engineers reviewing the 24LC025/ST datasheet, 24LC025/ST pinout, 24LC025/ST application, or 24LC025/ST equivalent, key selection considerations include its 6-lead SOT-23 package, absence of hardware write-protect (WP pin not connected), automotive-grade temperature range (–40°C to +125°C), and compatibility with standard I²C bus timing including Schmitt-trigger inputs and slope-controlled outputs.

Technical Context

The 24LC025/ST implements a two-wire I²C interface with slave address format '1010' followed by three chip-select bits (A2, A1, A0) and R/W bit - enabling up to eight devices on one bus (four in SOT-23 due to missing A2). Its internal architecture includes an address pointer, 16-byte page buffer, HV generator for EEPROM programming, and noise-suppression circuitry with Schmitt-trigger inputs and input filtering (50 ns spike suppression).

Unlike the 24LC024, the 24LC025/ST omits internal connection of the WP pin, eliminating hardware write protection. It uses self-timed erase/write cycles and supports acknowledge polling to detect write completion. Memory organization is fixed at 256 × 8-bit with contiguous addressing across multiple devices limited by software-managed address bit mapping (A0/A1 as A8/A9 in SOT-23).

Key Specifications

Pinout & Package

24LC025/ST is packaged exclusively in a 6-lead SOT-23 surface-mount package (3.0 mm × 1.7 mm × 1.1 mm), optimized for high-density PCB layouts. Pin 1 is marked by laser indentation; pin 3 is SDA (open-drain, requires external pull-up); pin 1 is SCL; pins 4 and 5 are A1 and A0 address inputs; pin 2 is VSS; pin 6 is VCC. The WP pin is not internally connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC024/ST, the 24LC025/ST removes write-protection capability but maintains identical endurance, speed, and packaging - making it ideal for applications requiring unrestricted write access. Versus AT24C02-SSHM-T, it adds automotive qualification and tighter AC timing specs at the cost of slightly higher unit price.

Availability

24LC025/ST is available at Aetrix Electronics and suitable for industrial sensor calibration, automotive body control modules, and medical device configuration requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 24LC025/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 24LCxx family was engineered specifically for reliable, low-power, I²C-based nonvolatile storage in automotive, industrial, and consumer systems - emphasizing robustness, long-term data integrity, and seamless integration into resource-constrained microcontroller platforms.

FAQ

What is the operating voltage range for the 24LC025/ST?

The 24LC025/ST operates from 2.5V to 5.5V. Operation below 2.5V is not supported - unlike the 24AA025 variant, which supports down to 1.7V. This makes the 24LC025/ST compatible with standard 3.3V and 5V supply rails but unsuitable for ultra-low-voltage battery-powered systems. The internal voltage detector disables write operations if VCC falls below approximately 1.5V, preventing corrupted data writes.

Does the 24LC025/ST have a hardware write-protect pin?

No, the 24LC025/ST does not have functional hardware write protection. Although the WP pin is physically present on the 6-lead SOT-23 package, it is not internally connected - as explicitly stated in the datasheet. This distinguishes it from the 24LC024/ST, which includes a fully functional WP pin tied to VCC/VSS. Write protection for the 24LC025/ST must therefore be implemented in software or system-level logic.

What package options are available for the 24LC025/ST?

The 24LC025/ST is available exclusively in the 6-lead SOT-23 package (3.0 mm × 1.7 mm × 1.1 mm). Unlike the 8-lead variants (PDIP, SOIC, TSSOP, DFN, MSOP), the SOT-23 version omits the A2 address pin and WP pin connection. This compact footprint supports high-density PCB layouts typical in automotive ECUs and portable electronics, while maintaining full 2 Kbit functionality and automotive temperature rating.

How many 24LC025/ST devices can be connected on a single I²C bus?

Up to four 24LC025/ST devices can share a single I²C bus. This limitation arises because the SOT-23 package lacks the A2 address pin, leaving only A1 and A0 to configure the slave address - yielding four unique combinations (00, 01, 10, 11). Each device responds to its assigned 7-bit address (1010xx0 or 1010xx1), enabling contiguous 8K-bit memory expansion when multiple units are deployed.

What is the maximum I²C clock frequency supported by the 24LC025/ST?

The 24LC025/ST supports a maximum I²C clock frequency of 400 kHz under standard operating conditions (VCC ≥ 2.5V). When VCC drops below 2.5V - though outside its specified range - timing degrades to 100 kHz. This fast-mode capability enables efficient configuration loading in time-critical applications, and the device's Schmitt-trigger inputs and controlled output slopes ensure signal integrity even at 400 kHz on moderately noisy buses.