Microchip Technology 11AA020-I/TO

Overview

11AA020-I/TO from Microchip Technology is a 2 Kbit (256 × 8) serial EEPROM using the UNI/O® single I/O bus interface, operating from 1.8V to 5.5V with 1 µA max standby current and 1 mA typical active current. It features Manchester-encoded communication at up to 100 kbps, 16-byte page-write buffer, and integrated write protection for industrial temperature applications (–40°C to +85°C). It is commonly used in space-constrained embedded systems for parameter storage and calibration data retention.

For engineers reviewing the 11AA020-I/TO datasheet, 11AA020-I/TO pinout, 11AA020-I/TO application, or 11AA020-I/TO equivalent, key selection considerations include its TO-92 package compatibility, 1.8V low-voltage operation, UNI/O® bus timing tolerance (±0.5% frequency drift per byte), Schmitt-trigger SCIO input for noise immunity, and block write protection covering 0%, 25%, 50%, or 100% of memory.

Technical Context

The 11AA020-I/TO implements a Manchester-encoded, master-controlled UNI/O® protocol over a single bidirectional SCIO line, eliminating need for separate clock or chip-select signals. Its internal architecture includes a 16-byte page latch, STATUS register with WIP/WEL/BP bits, and current-limited slope-controlled output driver to suppress ground bounce.

It supports self-timed write cycles (5–10 ms), automatic erase-before-write, and re-synchronization on every MAK bit to tolerate edge jitter (±0.06 UI) and frequency drift. Memory organization is fixed at 256 × 8 bits, with no address pins - device addressing uses hardwired 4-bit family code '1010' and 4-bit device code '0000'.

Key Specifications

Pinout & Package

11AA020-I/TO is housed in a 3-lead TO-92 package (top-down view: Pin 1 = VCC, Pin 2 = VSS, Pin 3 = SCIO). No NC pins are connected internally; all three terminals are functional.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 11LC020-I/TO, the 11AA020-I/TO enables direct integration into 1.8V microcontroller systems without level shifters; compared with AT24C02C-SSHM-T, it saves two GPIOs and simplifies routing but requires UNI/O®-capable firmware stack support.

Availability

11AA020-I/TO is available at Aetrix Electronics and suitable for industrial control systems, medical handheld devices, and IoT sensor nodes requiring stable component supply with long-term lifecycle assurance and RoHS-compliant packaging.

Supply support for 11AA020-I/TO 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 design and manufacturing operations.

The 11AA020-I/TO belongs to Microchip's UNI/O® Serial EEPROM family, designed specifically for ultra-low-pin-count embedded systems where minimizing GPIO usage and PCB area is critical without sacrificing reliability or voltage flexibility.

FAQ

What is the UNI/O® interface used by the 11AA020-I/TO, and how does it differ from I²C or SPI?

The 11AA020-I/TO uses Microchip's patented UNI/O® bus - a single-wire, Manchester-encoded serial interface that combines clock and data on one SCIO line. Unlike I²C (2-wire) or SPI (3–4 wires), it requires no separate clock, chip-select, or data-direction signals. This reduces GPIO count and PCB routing complexity. The 11AA020-I/TO implements this protocol with built-in re-synchronization logic to tolerate timing jitter and frequency drift, making it suitable for resource-constrained microcontrollers without dedicated hardware peripherals.

Does the 11AA020-I/TO support write protection, and how is it configured?

Yes, the 11AA020-I/TO includes configurable block write protection controlled via BP0/BP1 bits in its STATUS register. These bits - set using the WRSR command - allow locking 0%, 25%, 50%, or 100% of the 256-byte memory array against accidental writes. Protection is nonvolatile and persists across power cycles. Additionally, hardware write protection activates automatically at power-on (WEL reset) and during low-VCC conditions, ensuring memory integrity even during brown-out events.

What is the maximum write speed and timing behavior of the 11AA020-I/TO?

The 11AA020-I/TO performs self-timed write cycles with typical durations of 5 ms (byte or page) and up to 10 ms under worst-case conditions. During a write, the WIP bit in the STATUS register asserts high and remains active until completion - enabling software polling without fixed delays. The device supports up to 16-byte page writes, reducing total programming time versus sequential byte writes. No external timing components or wait states are required; the 11AA020-I/TO manages internal erase, program, and verify autonomously.

Can the 11AA020-I/TO operate reliably at 1.8V, and what are its current consumption specs?

Yes, the 11AA020-I/TO is fully specified for 1.8V operation across the industrial temperature range (–40°C to +85°C). At 1.8V, it draws ≤1 µA standby current (max) and ≤1 mA active current (typical) during read operations. Write current peaks at ≤3 mA (VCC = 2.5V) and scales with supply voltage. Its low-voltage capability eliminates need for level shifters when interfacing with modern 1.8V MCUs, and its Schmitt-trigger SCIO input ensures noise-immune signaling even at reduced logic thresholds.

What package and pinout does the 11AA020-I/TO use, and are there alternatives with same footprint?

The 11AA020-I/TO is supplied in a 3-lead TO-92 package with pinout: Pin 1 = VCC, Pin 2 = VSS, Pin 3 = SCIO (top-down view). This through-hole package is mechanically compatible with legacy sensor and control modules. Identical pinout variants exist across the 11AA/11LC family - including 11AA010-I/TO, 11AA040-I/TO, and 11LC020-I/TO - enabling drop-in density upgrades without PCB changes. No other manufacturer offers a functionally equivalent TO-92 UNI/O® EEPROM.