Microchip Technology 11LC040T-E/TT

Overview

11LC040T-E/TT from Microchip Technology Inc. is a 4 Kbit (512 × 8) serial EEPROM using the UNI/O® single I/O bus interface, operating from 2.5V to 5.5V across -40°C to +125°C automotive temperature range. It delivers 1 mA typical active current, 1 µA max standby current, and supports 100 kbps Manchester-encoded communication with 16-byte page-write buffering and hardware write protection.

For engineers reviewing the 11LC040T-E/TT datasheet, 11LC040T-E/TT pinout, 11LC040T-E/TT application, or 11LC040T-E/TT equivalent, key selection considerations include its SOT-23-3 automotive-grade packaging, UNI/O® protocol compatibility with PIC® MCUs, block-level write protection configuration, and guaranteed 1 million erase/write cycles with >200-year data retention.

Technical Context

The 11LC040T-E/TT implements a Manchester-encoded, master-controlled UNI/O® bus where clock and data share the SCIO line. Its internal architecture includes a status register with WIP and WEL bits, 16-byte page latches, and re-synchronization circuitry tolerant to ±0.5% frequency drift per byte and ±0.06 UI input edge jitter.

It features Schmitt-trigger SCIO input for noise immunity, slope-controlled output to suppress ground bounce, and hardware-based write protection covering none, 1/4, 1/2, or all memory array - enforced via BP0/BP1 bits in the nonvolatile STATUS register.

Key Specifications

Pinout & Package

11LC040T-E/TT is housed in a 3-lead SOT-23 package (TT suffix), with pin 1 = SCIO, pin 2 = VSS, pin 3 = VCC. No NC pins are present in this variant; all three terminals are functional and electrically defined per DS22067J.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 11LC040T-E/TT, the 11AA040T-I/TT offers wider voltage flexibility but lacks automotive qualification, while the AT24C04D-SSHM-T provides faster I²C throughput but demands additional PCB routing and firmware adaptation - neither is pin- or protocol-compatible.

Availability

11LC040T-E/TT is available at Aetrix Electronics and suitable for automotive control units, ADAS sensors, and body electronics requiring stable component supply with full AEC-Q100 alignment and long-term production support.

Supply support for 11LC040T-E/TT 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 manufacturer specializing in microcontrollers, analog devices, and memory solutions for industrial, automotive, and consumer markets.

The 11LC040T-E/TT belongs to Microchip's UNI/O® serial EEPROM family, designed specifically for space-constrained, cost-sensitive automotive subsystems requiring robust single-wire nonvolatile storage with extended temperature reliability.

FAQ

What is the UNI/O® interface used by the 11LC040T-E/TT, and how does it differ from I²C or SPI?

The 11LC040T-E/TT uses Microchip's patented UNI/O® bus - a single-wire, Manchester-encoded serial interface where clock and data share the SCIO line. Unlike I²C (2-wire) or SPI (3–4 wire), UNI/O® eliminates dedicated clock lines and requires only one GPIO, reducing MCU pin count and PCB complexity. It operates at up to 100 kbps and is fully supported by Microchip's PIC® MCUs with native firmware libraries.

Does the 11LC040T-E/TT require external components for reliable operation?

Yes - the 11LC040T-E/TT requires a 0.1 µF ceramic decoupling capacitor between VCC and VSS, placed within 2 mm of the device. A 10 kΩ pull-up resistor on the SCIO line is also mandatory to establish proper logic levels and enable Manchester decoding. No external clock source or level translators are needed due to its self-clocking design and 2.5–5.5V VCC compatibility.

How is write protection implemented on the 11LC040T-E/TT, and can it be changed in-system?

Write protection on the 11LC040T-E/TT is controlled by two nonvolatile BP0/BP1 bits in the STATUS register, configurable via the WRSR command. These bits enable locking 0%, 25%, 50%, or 100% of the memory array. Protection state persists across power cycles and can be modified in-system after issuing WREN - but requires explicit firmware handling and is not automatic on power-up.

What is the maximum write cycle time for the 11LC040T-E/TT, and how should firmware handle it?

The 11LC040T-E/TT specifies a maximum write cycle time of 10 ms for page or byte writes (TWC). Firmware must either poll the STATUS register's WIP bit via RDSR commands or wait the full 10 ms before initiating subsequent operations. Because WIP is readable during writes, non-blocking polling is recommended to minimize latency while ensuring completion before next access.

Is the 11LC040T-E/TT pin-compatible with other devices in the 11XX family, such as the 11LC020 or 11LC080?

Yes - all 11LCxxx devices in SOT-23-3 (TT) packaging, including 11LC020T-E/TT and 11LC080T-E/TT, share identical pinout (SCIO/VSS/VCC), voltage range (2.5–5.5V), temperature grade (-40°C to +125°C), and UNI/O® protocol. They differ only in density (2K/4K/8K) and device address (all use 0xA0), allowing direct substitution in layout when memory size requirements change.