Microchip Technology 11LC040T-I/SN

Overview

11LC040T-I/SN from Microchip Technology Inc. is a 4 Kbit serial EEPROM with UNI/O® single I/O bus interface, organized as 512 × 8 bits, operating from 2.5V to 5.5V, featuring 16-byte page write buffer, Schmitt-trigger SCIO input, and industrial temperature range (–40°C to +85°C). It is used in space-constrained embedded systems for parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 11LC040T-I/SN datasheet, 11LC040T-I/SN pinout, 11LC040T-I/SN application, or 11LC040T-I/SN equivalent, key selection considerations include its 3-lead SOT-23 package, 100 kbps Manchester-encoded bus timing, standby current ≤1 µA (I-temp), write endurance of 1 million cycles, and block write protection covering 0%, 25%, 50%, or 100% of memory array.

Technical Context

The 11LC040T-I/SN implements a Manchester-encoded, single-wire UNI/O® protocol where clock and data share the SCIO line, requiring master-controlled bit timing and slave-side re-synchronization on every MAK edge. Its internal architecture includes a status register with WIP and WEL flags, page latches supporting up to 16-byte writes, and hardware-based block protection controlled via BP0/BP1 bits.

It uses slope-controlled output drivers to suppress ground bounce, Schmitt-trigger inputs for noise immunity, and built-in power-on/off write protection. The device enters Standby mode after valid NoMAK/SAK termination and Idle mode upon invalid address or command - both requiring a standby pulse to recover.

Key Specifications

Pinout & Package

11LC040T-I/SN is packaged in a 3-lead SOT-23 (SN) variant, with SCIO serving as bidirectional serial clock/data I/O, VCC as supply voltage, and VSS as ground. No NC pins are present in this package.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 11AA040T-I/SN, the 11LC040T-I/SN trades lower-voltage operation for improved noise immunity and tighter VCC regulation - making it preferable in electrically harsh industrial settings. Against 24LC04B-I/SN, it offers superior pin efficiency and simpler routing but demands UNI/O®-capable host firmware.

Availability

11LC040T-I/SN is available at Aetrix Electronics and suitable for smart sensor calibration storage, industrial PLC configuration memory, and medical device usage log applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 11LC040T-I/SN 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory products, with a focus on embedded control and connectivity solutions.

The 11LC040T-I/SN belongs to Microchip's 11XX family of UNI/O® serial EEPROMs, designed specifically for ultra-low-pin-count, low-power, and space-constrained embedded applications where traditional 2-wire or 3-wire interfaces are impractical.

FAQ

What is the UNI/O® bus interface used by the 11LC040T-I/SN?

The 11LC040T-I/SN uses Microchip's patented UNI/O® single I/O bus, which combines clock and data onto one bidirectional line (SCIO) using Manchester encoding. This eliminates separate clock lines, reduces MCU pin count, and simplifies PCB layout. The master controls timing, while the 11LC040T-I/SN extracts clock from the bit stream and resynchronizes on each MAK edge to tolerate frequency drift and jitter.

Does the 11LC040T-I/SN support write protection, and how is it configured?

Yes, the 11LC040T-I/SN supports hardware block write protection via two nonvolatile BP0 and BP1 bits in its STATUS register. These bits are set using the WRSR command and enable protection of 0%, 25%, 50%, or 100% of the memory array. Protection is active immediately after WRSR execution and persists through power cycles - preventing accidental writes to critical configuration sectors.

What is the maximum write speed and page size of the 11LC040T-I/SN?

The 11LC040T-I/SN has a fixed page size of 16 bytes and supports page writes up to that limit. A full page write completes in ≤10 ms (TWC), while individual byte writes take ≤5 ms. The device does not support faster write modes - all writes are self-timed and internally managed, with the WIP bit indicating completion status via RDSR polling.

Can the 11LC040T-I/SN operate at 1.8V supply voltage?

No, the 11LC040T-I/SN is specified for 2.5V to 5.5V operation only. For 1.8V compatibility, Microchip offers the pin-compatible 11AA040T-I/SN variant, which shares identical density, page size, UNI/O® protocol, and SOT-23 package but extends VCC down to 1.8V. Using 11LC040T-I/SN below 2.5V may result in unreliable communication or failed writes.

How does the 11LC040T-I/SN handle power-loss during a write operation?

The 11LC040T-I/SN includes built-in power-on/off write protection circuitry that inhibits writes during brown-out conditions. If VCC drops below the functional threshold during a write cycle, the internal charge pump halts, and the operation aborts safely. No partial writes occur - the memory remains unaltered until a subsequent valid write command with proper VCC and WREN sequence is issued.