Microchip Technology 24LC1026-E/ST

Overview

24LC1026-E/ST from Microchip Technology is a 128K × 8 (1024 Kbit) I²C-compatible serial EEPROM with automotive-grade temperature range (–40°C to +125°C), 2.5V–5.5V supply, 400 kHz max clock (100 kHz at V_CC < 4.5V in E-temp), 128-byte page write buffer, and hardware write-protection via WP pin. It supports cascading up to four devices on one bus for up to 4 Mbit system memory and is used in engine control units, ADAS sensor modules, and automotive infotainment firmware storage.

For engineers reviewing the 24LC1026-E/ST datasheet, 24LC1026-E/ST pinout, 24LC1026-E/ST application, or 24LC1026-E/ST equivalent, key selection criteria include its AEC-Q100-qualified automotive operating range, Schmitt-trigger noise immunity on SDA/SCL, self-timed 5 ms max write cycle, >1 million endurance cycles, and 200+ year data retention - all validated for under-hood and safety-critical embedded systems.

Technical Context

The 24LC1026-E/ST implements a two-wire I²C slave interface with fixed 4-bit control code (1010b), user-configurable A1/A2 address bits enabling up to four devices per bus, and B0 block-select bit for accessing two 512 Kbit memory segments (00000h–0FFFFh and 10000h–1FFFFh). Its internal address pointer auto-increments during sequential reads and wraps within each segment.

It uses Schmitt-trigger inputs on SDA and SCL (hysteresis ≥0.05 V_CC) and slope-controlled outputs to suppress ground bounce. Write protection is hardware-enforced: tying WP to V_CC disables all writes while permitting reads; WP sampling occurs at the Stop bit of each write command.

Key Specifications

Pinout & Package

24LC1026-E/ST is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with 3.90 mm body width, RoHS-compliant matte tin lead finish, and standard JEDEC MS-012AA footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24CS1026-SSHL-T and BR24T1026FJ-WE2, the 24LC1026-E/ST delivers verified automotive qualification, deterministic 400 kHz timing at full temperature range, and hardware write protection aligned with legacy ECU architectures - making it the preferred choice for retrofit and Tier-1 production programs where design continuity and qualification evidence are mandatory.

Availability

24LC1026-E/ST is available at Aetrix Electronics and suitable for automotive engine control, ADAS sensor calibration, and infotainment user-profile storage requiring stable component supply across extended product lifecycles.

Supply support for 24LC1026-E/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 24LC1026-E/ST belongs to Microchip's automotive-qualified serial EEPROM product line, engineered specifically for robust, long-life nonvolatile data storage in harsh-temperature automotive subsystems where reliability and qualification evidence are non-negotiable.

FAQ

What is the maximum I²C clock frequency supported by the 24LC1026-E/ST across its full automotive temperature range?

The 24LC1026-E/ST supports up to 400 kHz I²C clock frequency when V_CC ≥ 4.5V and ambient temperature is –40°C to +125°C. At V_CC < 4.5V under automotive conditions, the maximum clock is 100 kHz - a derating explicitly specified in Microchip's DS20002270E datasheet Section 1.2 and Table 1-2. This ensures timing margin compliance during cold-cranking voltage drops.

How does the WP pin function on the 24LC1026-E/ST, and when is it sampled during write operations?

The WP (Write-Protect) pin on the 24LC1026-E/ST is an active-high hardware lock: when tied to V_CC, all write operations (byte and page) are inhibited while reads remain fully functional. The device samples the WP state only at the Stop bit of each write command - toggling WP after the Stop bit has no effect on an ongoing write cycle, as confirmed in Section 6.3 of the official datasheet.

Can the 24LC1026-E/ST perform sequential reads across its entire 1024 Kbit memory space without interruption?

No. Sequential reads on the 24LC1026-E/ST are limited to 512 Kbit address boundaries: 00000h–0FFFFh and 10000h–1FFFFh. The internal address pointer rolls over at each boundary (e.g., from 0FFFFh back to 00000h), preventing seamless read-through of the full memory array. To access both blocks, software must issue separate read commands with appropriate B0 block-select bit settings.

What is the page write time specification for the 24LC1026-E/ST, and how does it impact firmware update latency?

The 24LC1026-E/ST has a typical page write time of 3 ms and a maximum of 5 ms per page (128 bytes), as stated in the Features section and Table 1-2 (TWC). This means a full 1024 Kbit firmware patch written in optimal 128-byte pages requires ≤40 ms total write time - significantly faster than byte-write mode and enabling responsive OTA updates in automotive gateways without blocking critical real-time tasks.

Is the 24LC1026-E/ST pin-compatible with other members of the 24XX1026 family, such as the 24AA1026 or 24FC1026?

Yes - the 24LC1026-E/ST shares identical 8-pin SOIC pinout, terminal functions, and package dimensions with the 24AA1026 and 24FC1026. However, electrical differences exist: the 24LC1026-E/ST requires minimum 2.5V V_CC and supports 400 kHz (not 1 MHz like the 24FC1026), so direct substitution requires verification of voltage and timing compatibility in the target application.