Microchip Technology 11AA020T-I/MS

Overview

11AA020T-I/MS from Microchip Technology Inc. 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 serial 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 11AA020T-I/MS datasheet, 11AA020T-I/MS pinout, 11AA020T-I/MS application, or 11AA020T-I/MS equivalent, key selection considerations include its single-pin UNI/O® interface compatibility, 1.8V low-voltage operation, page-write timing (≤10 ms), STATUS register access for WIP/WEL monitoring, and MSOP-8 package footprint constraints.

Technical Context

The 11AA020T-I/MS implements a Manchester-encoded, master-controlled UNI/O® bus protocol on a single SCIO pin, eliminating separate clock lines and reducing PCB routing complexity. Its internal architecture includes a 16-byte page latch, STATUS register with WIP and WEL bits, and hardware-based block write protection (BP0/BP1) configurable via WRSR command.

It supports dynamic re-synchronization during each MAK bit to tolerate frequency drift (±0.5% per byte) and edge jitter (±0.06 UI), enabling robust operation in electrically noisy environments. The device enters Standby mode after NoMAK/SAK termination or explicit standby pulse, drawing ≤1 µA at 85°C.

Key Specifications

Pinout & Package

11AA020T-I/MS is housed in an 8-lead MSOP (MS) package, measuring 3.0 mm × 3.0 mm × 1.0 mm, with exposed pad option not specified. Pin 1 is SCIO (bidirectional serial clock/data), Pin 2 is VSS (ground), Pin 3 is NC (no connect), Pin 4 is NC, Pin 5 is NC, Pin 6 is NC, Pin 7 is NC, Pin 8 is VCC (supply voltage).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C02C-SSHM-T and 24AA02E48-I/MS, the 11AA020T-I/MS delivers lowest pin count and lowest standby current (1 µA) but requires UNI/O®-capable firmware stack; neither alternative offers native page-write status visibility or identical single-pin timing behavior.

Availability

11AA020T-I/MS is available at Aetrix Electronics and suitable for industrial control systems, medical diagnostics equipment, and IoT sensor nodes requiring stable component supply, long-life data retention, and compact 8-pin MSOP packaging.

Supply support for 11AA020T-I/MS 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 11AA020T-I/MS 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 multi-wire interfaces are impractical.

FAQ

What is the maximum operating frequency of the 11AA020T-I/MS UNI/O® bus?

The 11AA020T-I/MS supports a maximum serial bus frequency of 100 kHz, corresponding to a minimum bit period of 10 µs. This limit is defined by AC timing parameter FBUS and applies across the full 1.8V–5.5V VCC range and –40°C to +85°C temperature range. Exceeding this frequency may cause synchronization loss or NoSAK responses due to timing violations in the Manchester decoder.

Does the 11AA020T-I/MS require external pull-up resistors on the SCIO line?

Yes, the 11AA020T-I/MS requires an external pull-up resistor on the SCIO line - typically 4.7 kΩ to VCC - to ensure proper logic high levels during idle and standby states. The internal SCIO driver is open-drain-like in behavior during output, and the pull-up establishes the default high state needed for start-header detection and bus arbitration.

How is write protection configured on the 11AA020T-I/MS?

Write protection on the 11AA020T-I/MS is controlled via BP0 and BP1 bits in the STATUS register, set using the WRSR (Write Status Register) command. These bits enable protection of 0%, 25%, 50%, or 100% of the memory array. Protection is nonvolatile and persists through power cycles. The 11AA020T-I/MS does not support software write-protection disable via command - only hardware reset or WRSR overwrite clears it.

Can the 11AA020T-I/MS be used with a 1.8V-only microcontroller without level shifting?

Yes, the 11AA020T-I/MS operates natively from 1.8V to 5.5V and is fully compatible with 1.8V I/O logic levels. Its VIH threshold is 0.7×VCC (≥1.26V at 1.8V), and VIL is ≤0.3×VCC (≤0.54V), ensuring reliable recognition of 1.8V MCU outputs. No level shifter is needed when interfacing with 1.8V microcontrollers such as PIC16F1xxx or STM32L0x series.

What happens if a write command is issued without first sending WREN to the 11AA020T-I/MS?

If a WRITE command is sent to the 11AA020T-I/MS without prior execution of the WREN (Write Enable) instruction, the device ignores the write data and returns a NoSAK after the command byte. The internal write enable latch remains cleared, and no memory location is modified. The STATUS register WEL bit stays '0', confirming write disable state - this behavior is hardware-enforced and cannot be overridden.