Microchip Technology 24LC1026T-I/ST

Overview

24LC1026T-I/ST from Microchip Technology is a 128K × 8 (1024 Kbit) I²C-compatible serial EEPROM with hardware write-protection, 128-byte page buffer, and industrial temperature range (–40°C to +85°C). It operates from 2.5V to 5.5V, supports up to 400 kHz clock frequency, and delivers ≤450 µA read current and ≤5 µA standby current - enabling low-power data logging in embedded control systems.

For engineers reviewing the 24LC1026T-I/ST datasheet, 24LC1026T-I/ST pinout, 24LC1026T-I/ST application, or 24LC1026T-I/ST equivalent, key selection criteria include VCC voltage compatibility (2.5–5.5V), I²C bus timing compliance (THIGH ≥600 ns at 400 kHz), WP pin logic behavior (VSS = enable write), and cascading support via A1/A2 address pins for multi-device memory expansion.

Technical Context

The 24LC1026T-I/ST implements a two-wire I²C interface with Schmitt-trigger inputs on SDA/SCL for noise immunity and slope-controlled outputs to suppress ground bounce. Its internal architecture includes dual 512 Kbit memory blocks addressed via block-select bit B0, requiring explicit addressing across 00000h–0FFFFh and 10000h–1FFFFh boundaries.

Write operations are self-timed and support both byte- and page-write modes (up to 128 bytes per page), with automatic address pointer increment and wraparound handling. Hardware write-protection is enforced by sampling the WP pin at the Stop condition, making it immune to mid-cycle toggling.

Key Specifications

Pinout & Package

24LC1026T-I/ST uses an 8-lead SOIC package (3.90 mm width), RoHS-compliant, with gull-wing leads and standard JEDEC MS-012AC footprint. Pin 1 is marked with a beveled corner or dot.

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 24LC1026T-I/ST provides optimal balance of industrial-grade voltage margin (2.5V min), 400 kHz performance, and hardware-enforced write protection - making it preferred for safety-aware and maintenance-critical embedded systems where accidental overwrite must be physically prevented.

Availability

24LC1026T-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration storage, medical device configuration backup, and automotive body control modules requiring stable component supply across extended product lifecycles.

Supply support for 24LC1026T-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, FPGA, and memory solutions, serving industrial, automotive, and consumer markets with high-reliability silicon and development tools.

The 24LC1026T-I/ST belongs to Microchip's serial EEPROM product line, engineered for robust, low-power nonvolatile data storage in space-constrained embedded systems where write endurance, data integrity, and I²C interoperability are critical.

FAQ

What is the minimum VCC voltage required for reliable operation of the 24LC1026T-I/ST?

The 24LC1026T-I/ST requires a minimum VCC of 2.5V for guaranteed operation across its full industrial temperature range (–40°C to +85°C). Below 2.5V, the device is not characterized - attempting operation risks incomplete writes, failed ACK polling, or corrupted data reads. This differs from the 24AA1026 variant, which supports 1.7V. Always verify regulator output stability under load before deploying 24LC1026T-I/ST in battery-backed or low-voltage designs.

How does the WP pin function on the 24LC1026T-I/ST, and when is it sampled?

The WP (Write-Protect) pin on the 24LC1026T-I/ST is sampled only at the Stop condition of each I²C write command. When tied to VCC, it disables all write operations (byte and page) while permitting unrestricted reads. When tied to VSS, writes are enabled. Toggling WP during an active write cycle has no effect - protection state is latched at Stop, ensuring immunity to noise or glitch-induced changes. This behavior makes 24LC1026T-I/ST suitable for systems where firmware must prevent runtime corruption.

Can the 24LC1026T-I/ST perform sequential reads across its full 1024 Kbit address space?

No. The 24LC1026T-I/ST divides its memory into two independent 512 Kbit blocks (00000h–0FFFFh and 10000h–1FFFFh), and sequential reads automatically roll over within each block but cannot cross the boundary between them. To read the full array sequentially, the master must issue separate read commands - one for each block - with appropriate block-select bit (B0) setting in the control byte. This architectural constraint is inherent to the 24LC1026T-I/ST's internal addressing scheme.

What is the maximum number of 24LC1026T-I/ST devices that can share the same I²C bus, and how is addressing managed?

Up to four 24LC1026T-I/ST devices can share a single I²C bus using the A1 and A2 address pins. These pins configure the two least-significant bits of the 7-bit slave address (base 0x50), yielding addresses 0x50–0x53. Each device must have a unique A1/A2 combination (e.g., 00, 01, 10, 11), hardwired to VSS or VCC. No external address decoder is needed - the I²C master selects a device by sending its specific address in the control byte.

Does the 24LC1026T-I/ST support 1 MHz I²C clock operation?

No. The 24LC1026T-I/ST supports a maximum I²C clock frequency of 400 kHz at VCC ≥ 2.5V. For 1 MHz operation, Microchip offers the 24FC1026 variant - which shares the same pinout and memory architecture but is specified for 1 MHz at VCC ≥ 2.5V. Using 24LC1026T-I/ST at 1 MHz violates AC timing specifications (e.g., THIGH minimum becomes 500 ns), risking data corruption or bus lockup. Always match clock speed to the exact variant's datasheet limits.