Microchip Technology 93AA66BT-I/MC

Overview

93AA66BT-I/MC from Microchip Technology is a 4 Kbit low-voltage serial EEPROM with 512 × 8-bit organization, Microwire-compatible 3-wire interface (CS/CLK/DI/DO), and industrial temperature range (–40°C to +85°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and 1,000,000 endurance cycles - used in embedded system configuration storage and calibration data retention.

For engineers reviewing the 93AA66BT-I/MC datasheet, 93AA66BT-I/MC pinout, 93AA66BT-I/MC application, or 93AA66BT-I/MC equivalent, key selection criteria include V_CC range (1.8–5.5 V), 8-bit x512 memory map, DFN-8 package footprint, Ready/Busy status via DO pin, and compatibility with legacy Microwire controllers in space-constrained industrial modules.

Technical Context

The 93AA66BT-I/MC implements a synchronous serial interface with start-bit detection, opcode-driven instruction set (READ/ WRITE/ERASE/ERAL/WRAL/EWEN/EWDS), and dual-mode operation: dedicated 8-bit communication (no ORG pin function). It uses internal auto-erase prior to write and supports sequential read without address retransmission.

Memory access requires CS high, CLK rising-edge synchronization for DI input and DO output, and explicit EWEN command to enable programming - with automatic return to EWDS after power-up or V_CC dropout. The DO pin serves dual role: data output during READ and Ready/Busy indicator during erase/write.

Key Specifications

Pinout & Package

Package: 8-lead 2×3 mm DFN (MC suffix), exposed pad (may be connected to VSS or left floating), Pb-free Matte Tin finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93AA66AT-I/MC, the 93AA66BT-I/MC offers identical functionality and pinout but is specifically designated for B-version marking - both are drop-in replacements. Versus AT25DF041A-MAU-T, it provides true EEPROM behavior (byte-write, no erase-before-write) essential for parameter storage with unpredictable update patterns.

Availability

93AA66BT-I/MC is available at Aetrix Electronics and suitable for industrial motor control, sensor calibration, and medical device usage logging requiring stable component supply, long-term obsolescence management, and RoHS-compliant packaging.

Supply support for 93AA66BT-I/MC 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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93XX Series EEPROMs were designed for low-power, board-space-constrained embedded systems requiring reliable, byte-addressable nonvolatile storage - especially where Microwire interface compatibility and hardware data protection are critical.

FAQ

What is the memory organization of the 93AA66BT-I/MC?

The 93AA66BT-I/MC is a 512 × 8-bit (4 Kbit) serial EEPROM with fixed x8 organization. As an 'A' variant, it does not use the ORG pin - that pin is internally disconnected (NC) and must be left unconnected. This distinguishes it from 'B' (x16) and 'C' (configurable x8/x16) versions. The 93AA66BT-I/MC delivers consistent 8-bit word access without external configuration logic.

Does the 93AA66BT-I/MC require an external pull-up resistor on the DO pin?

No, the 93AA66BT-I/MC does not require an external pull-up on DO. During READ, DO actively drives high/low logic levels; during READY/READY-BUSY polling, it outputs valid logic states. However, if DI and DO are shorted (shared bus), a series resistor (typically 1–10 kΩ) is required to prevent bus conflict during the dummy zero phase - as specified in Section 2.2 of the 93AA66BT-I/MC datasheet.

How is write protection implemented on the 93AA66BT-I/MC?

Write protection on the 93AA66BT-I/MC is implemented via hardware power-on reset and software commands: the device powers up in Erase/Write Disable (EWDS) state, and an EWEN command must precede any ERASE or WRITE. After each write, issuing EWDS restores protection. Additionally, V_CC below 1.5 V disables all programming - providing robust brown-out immunity. No external WP pin is present on the 93AA66BT-I/MC.

What package type does the 93AA66BT-I/MC use, and what are its key mechanical features?

The 93AA66BT-I/MC uses an 8-lead 2×3 mm DFN (Dual Flat No-lead) package with exposed thermal pad (MC suffix). Its footprint measures 2.0 mm × 3.0 mm × 0.75 mm max height. The exposed pad may be connected to VSS for improved thermal dissipation or left floating. It is Pb-free with Matte Tin finish and complies with JEDEC MO-229 standards - verified in Microchip's DS21795E packaging drawings.

Can the 93AA66BT-I/MC be used with SPI controllers?

The 93AA66BT-I/MC is Microwire-compatible, not SPI-compatible. While both use 4-wire serial interfaces, Microwire requires strict start-bit detection, specific opcode framing (11/10/01/etc.), and no CPOL/CPHA configuration. Direct connection to standard SPI masters will fail without bit-banging or protocol translation. The 93AA66BT-I/MC must be driven by a true Microwire controller or GPIO-based bit-banged interface per DS21795E timing diagrams.