Microchip Technology 24LC1026-I/ST

Overview

24LC1026-I/ST from Microchip Technology is a 128K × 8 (1024 Kbit) I²C-compatible serial EEPROM with industrial temperature range (–40°C to +85°C), 2.5V–5.5V supply voltage, and 400 kHz maximum clock frequency. It features 128-byte page write buffer, hardware write-protect (WP pin), and Schmitt-trigger inputs for noise immunity-used in embedded system configuration storage, sensor calibration data retention, and firmware parameter backup.

For engineers reviewing the 24LC1026-I/ST datasheet, 24LC1026-I/ST pinout, 24LC1026-I/ST application, or 24LC1026-I/ST equivalent, key selection criteria include VCC operating range compatibility, I²C bus timing compliance at target clock speed, WP pin control logic, and page boundary handling in firmware.

Technical Context

The 24LC1026-I/ST implements a two-wire I²C slave interface with fixed 4-bit control code (1010b) and user-configurable A1/A2 address bits enabling up to four devices on one bus. Its internal memory is split into two 512 Kbit blocks selected by the B0 bit, requiring explicit block addressing for full 1024 Kbit access.

Write operations support byte and page modes (up to 128 bytes), with self-timed erase/write cycles (typ. 3 ms), automatic address pointer increment, and ACK polling for cycle completion detection. The device uses on-chip HV generation for programming and includes slope-controlled outputs to suppress ground bounce.

Key Specifications

Pinout & Package

24LC1026-I/ST is supplied in an 8-lead SOIC package (3.90 mm width), RoHS-compliant, with standard JEDEC MS-012AC footprint and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA1026-I/ST and AT24C1024-SSHL-T, the 24LC1026-I/ST provides optimal balance of industrial temperature rating, proven I²C timing compliance at 400 kHz, and hardware write-protect simplicity-making it preferred for cost-sensitive, thermally stable embedded systems where sub-2.5V operation is unnecessary.

Availability

24LC1026-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration storage, medical device configuration backup, and automotive ECU bootloader settings requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for 24LC1026-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 is a leading provider of microcontrollers, analog components, and nonvolatile memory solutions, serving industrial, automotive, and consumer markets with high-reliability silicon and development tools.

The 24LC1026 belongs to Microchip's serial EEPROM product line, designed specifically for robust, low-power, I²C-based configuration and calibration data storage in harsh environmental conditions.

FAQ

What is the minimum VCC voltage required for reliable operation of the 24LC1026-I/ST?

The 24LC1026-I/ST requires a minimum VCC of 2.5V for guaranteed operation across its full industrial temperature range (–40°C to +85°C). Operation below 2.5V is not characterized and may result in undefined behavior, including I²C timing violations or incomplete write cycles. This distinguishes it from the 24AA1026 variant, which supports down to 1.7V.

How does the WP pin function on the 24LC1026-I/ST, and when is it sampled?

The WP pin on the 24LC1026-I/ST is sampled at the Stop bit of each write command. When tied to VCC, it inhibits all write operations (byte and page) while allowing unrestricted reads. Tying WP to VSS enables writes. Toggling WP after the Stop bit has no effect-the state is latched only once per command, ensuring deterministic protection during power transients.

Can the 24LC1026-I/ST perform sequential reads across its entire 1024 Kbit memory space?

No. Sequential reads on the 24LC1026-I/ST are limited to 512 Kbit blocks due to internal addressing architecture. The memory is split into two segments (00000h–0FFFFh and 10000h–1FFFFh), selected by the B0 bit in the control byte. To read across both blocks, the host must issue separate read commands with B0 toggled-no automatic rollover occurs between segments.

What is the maximum number of 24LC1026-I/ST devices that can share the same I²C bus, and how is addressing managed?

Up to four 24LC1026-I/ST devices can share one I²C bus using the A1 and A2 pins to configure unique 2-bit chip select codes (00, 01, 10, 11). These bits form the two least-significant bits of the 7-bit slave address (1010 A2 A1 B0), enabling independent addressing without external multiplexing. Each device must have a distinct A1/A2 combination.

Does the 24LC1026-I/ST support 1 MHz I²C clock operation?

No. The 24LC1026-I/ST supports a maximum clock frequency of 400 kHz at VCC ≥ 2.5V. For 1 MHz operation, the 24FC1026 variant is required-it is explicitly rated for 1 MHz at VCC ≥ 2.5V. Using 24LC1026-I/ST at 1 MHz violates AC specifications and may cause data corruption or failed ACKs.